Dagobert D. Runes, Dictionary of Philosophy, 1942.
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Paganism: (Lat. pagus, village) The term probably reverts to the designation of villagers who had not yet been reached by the missionary propaganda emanating from populous centers. Fourth-century Christians employed the term to refer to those faiths and practices outside the circumference of the Christian faith. -- V.F.
Pai chia: The "Hundred Schools," referring to the various tendencies of thought in philosophy, logic, ethics, law, politics, diplomacy, economics, agriculture, military science, etc, in the third and fourth centuries B.C. with Chi Hsia as a center. -- W.T.C.
Pain: See Pleasure.
Painting: A plane surface covered with colors assembled in a given order (M. Denis, 1890). -- L.V.
Paley, William: (1743-1805) Was an English churchman well known for a number of works in theology. He is also widely remembered in the field of ethics. His Principles of Moral and Political Philosophy passed through many editions and served as a text book at Cambridge for many years. As an advocate of the doctrine of expediency, he gave impetus to the later Utilitarian School. He maintained that the beneficial tendency is what makes an action right. See Utilitarianism. Cf W. Paley, Horae Paulinae, 1790; View of the Evidences of Christianity, 1794; Natural Theology, 1802. -- L.E.D.
Palingenesis: (Gr palm, again, genesis, birth) Literally, a new birth or regeneration A rebirth of ideas and events (in a philosophy of history), a new birth of individuals (in theology). -- V.F.
Panaetius: (180-110 B.C.) A prominent Stoic philosopher whose thought was influenced by the Skeptics; in his attempt to adapt Stoicism to practical needs of life, he abandoned some of the more speculative notions current among his predecessors. Influenced Cicero and Augustine. -- R.B.W.
Parcaratra: (Skr ) A quasi philosophical system of Vishnuism (q.v.) based upon the Agamas (q.v.). -- K.F.L.
Pan-entheism: (Gr. pan, all; en, in, theos, god) The term for the view that God interpenetrates everything without cancelling the relative independent existence of the world of entities, moreover, while God is immanent, this immanence is not absolute (as in pantheism), God is more than the world, transcendent, in the sense that though the created is dependent upon the Creator the Creator is not dependent upon the created. God thus is held to be the highest type of Unity, viz., a Unity in Multiplicity. The term is employed to cover a mediating position between pantheism with its extreme immanence and a theism of the type which tends to extreme transcendence- -- V.F.
Panlogism: (Gr. pan, all + logos, word) The doctrine that the world is the actualization of Mind or Logos. Term applied to Hegel's theory of Reality. See Hegel. -- L.W.
Pan-objectivism: (Gr. pan, all + Lat. objectus, pp. of objicere, to throw over against) An extreme form of epistemological realism which attributes real ohjectivity to all objects of knowledge, veridical and non-veridical alike. See Epistemological Realism. -- L.W.
Panpneumatism: According to Ed. v. Hartmmn (q.v.) a synthesis of panlogism and pantheism (q.v.). -- K.F.L.
Panpsychism: (Gr pan, all, psyche, soul) A form of metaphysical idealism, of which Leibniz's theory of monads is the classical example, according to which the whole of nature consists of psychic centers similar to the human mind. -- L.W.
Pan-Satanism: The vague belief that the world is somehow identified with the devil. Name given to pantheism by Herbart. Otto Liebmann (1840-1912) regarded Schopenhauer's philosophy as a sort of Pan-Satanism. -- J.J.R.
Pantheism: (Gr. Pan, all; Theos, God)

1. The doctrine that reality comprises a single being of which all things are modes, moments, members, appearances, or projections.

2. As a religious concept Pantheism is to be distinguished from Immanent Theism md Deism by asserting the essential imminence of God in the creatures. See Monism, Idealism -- W.L.

Pantheism, medieval: True pantheistic ideas are rare in medieval literature. The accusation raised against Scotus Eriugena seems unfounded and was caused more by his writings being quoted as authorities by the followers of Amalric of Bene (1206-7) whose views were condemned in 1210. His writings are lost, he apparently taught the identity of Creator and creature and called God the essence of all beings A contemporary was David of Dinant of whom still less is known, he identified, as it seems, God with prime matter. Master Eckhardt too has been accused of pantheism and some modern authors have believed to find confirmation in his writings. A more thorough study of them, especially of the Latin texts, shows this to be a misinterpretation. -- R.A.
Pantheistic Personalism: The doctrine that reality consists of a Supreme Personality of which the world of persons are parts. The Divine Personality having no separate existence from its creation. See also Critical Personalism, Mono-Personalism. -- R.T.F.
Paracelsus, Theophrastus Bombast: (1493-1541) Of Hohenheim, was a physician who endeavored to use philosophy as one of the "pillars" of medical science. His philosophy is a weird combination of Neo-Platonism, experimentalism, and superstitious magic. He rejected much of the traditional theory of Galen and the Arab physicians. His works (Labyrinthus, Opus paramirum, Die grosse Wundarznei, De natura rerum) were written in Swiss-German, translated into Latin by his followers, recent investigators make no attempt to distinguish his personal thought from that of his school. Thorndyke, L., Hist. of Magic and Experimental Science (N. Y., 1941), V, 615-651. -- V.J.B.
Paraclete: (Gr. parakaleo, to call to one's aid) One who is called to assistance. More specifically: the designation of the function of the Holy Spirit, the third embodiment of the Christian Trinity. -- V.F.
Paradigma: The Latin foim of the Greek noun, which denotes model. Plato called his ideas in the world of ideas, models on which were patterned the things of the phenomenal world. -- J.J.R.
Paradoxes, logical: The ancient paradox of Epimenides the Cretan, who said that all Cretans were liars (i.e., absolutely incapable of telling the truth), was known under numerous variant forms in ancient and medievd times The medieval name for these was insolubilia.

A form of this paradox due to Jourdain (1913) supposes a card upon the front of which are written the words, "On the other side of this card is written a true statement" -- and nothing else. It seems to be clear that these words constitute a significant statement, since, upon turning the card over one must either find some statements written or not, and, in the former case, either there will be one of them which is true or there will not. However, on turning the card over there appear the words. "On the other side of this card is written a false statement" -- and nothing else. Suppose the statement on the front of the card is true, then the statement on the back must be true, and hence the statement on the front must be false. This is a proof by reductio ad absurdum that the statement on the front of the card is false. But if the statement on the front is false, then the statement on the back must be false, and hence the statement on the front must be true. Thus the paradox.

A related but different paradox is Grelling's (1908). Let us distinguish adjectives -- ie, words denoting properties -- as autological or i according as they do or do not have the property which they denote (in particular, adjectives denoting properties which cannot belong to words at all will be heterological). Then, e.g., the words polysyllabic, common, significant, prosaic are autological, while new, alive, useless, ambiguous, long are heterological. On their face, these definitions of autological and heterological are unobjectionable (compare the definition of onomatopoetic as similar in sound to that which it denotes). But paradox arises when we ask whether the word heterological is autological or heterological.

That paradoxes of this kind could be relevant to mathematics first became clear in connection with the paradox of the greatest ordinal number, published by Burali-Forti in 1897, and the paradox of the greatest cardinal number, published by Russell in 1903. The first of these had been discovered by Cantor in 1895, and communicated to Hilbert in 1896, and both are mentioned in Cantor's correspondence with Dedekind of 1899, but were never published by Cantor.

From the paradox of the greatest cardinal number Russell extracted the simpler paradox concerning the class t of all classes x such that ∼ x∈x. (Is it true or not that t∈t?) At first sight this paradox may not seem to be very relevant to mathematics, but it must be remembered that it was obtained by comparing two mathematical proofs, both seemingly valid, one leading to the conclusion that there is no greatest cardinal number, the other to the conclusion that there is a greatest cardinal number. -- Russell communicated this simplified form of the paradox of the greatest cardinal number to Frege in 1902 and published it in 1903. The sime paradox wis discovered independently by Zermelo before 1903 but not published.

Also to be mentioned are König's paradox (1905) concerning the least undefinable ordinal number and Richard's paradox (1905) concerning definable and undefinable real numbers.

Numerous solutions of these paradoxes have been proposed. Many, however, have the fault that, while they purport to find a flaw in the arguments leading to the paradoxes, no effective criterion is given by which to discover in the case of other (e.g., mathematical) proofs whether they have the same flaw.

Russell's solution of the paradoxes is embodied in what is now known as the ramified theory of types, published by him in 1908, and afterwards made the basis of Principia Mathematica. Because of its complication, and because of the necessity for the much-disputed axiom of reducibility, this has now been largely abandoned in favor of other solutions.

Another solution -- which has recently been widely adopted -- is the simple theory of types (see Logic, formal, § 6). This was proposed as a modification of the ramified theory of types by Chwistek in 1921 and Ramsey in 1926, and adopted by Carnap in 1929.

Another solution is the Zermelo set theory (see Logic, formal, § 9), proposed by Zermelo in 1908, but since considerably modified and im proved.

Unlike the ramified theory of types, the simple theory of types and the Zermelo set theory both require the distinction (first made by Ramsey) between the paradoxes which involve use of the name relation (q.v.) or the semantical concept of truth (q.v.), and those which do not. The paradoxes of the first kind (Epimenides, Grelling's, König's, Richard's) are solved by the supposition that notations for the name relation and for truth (having the requisite formal properties) do not occur in the logistic system set up -- and in principle, it is held, ought not to occur. The paradoxes of the second kind (Burali-Forti's, Russell's) are solved in each case in another way. -- Alonzo Church

G. Frege,
Grundgesetze der Anthmetik, vol 2, Jena, 1903 (see Appendix).
B. Russell,
The Principles of Mathematics, Cambridge, England, 1903; 2nd edn. London, 1937, and New York, 1938.
Grelling and Nelson,
Bemerkungen zu den Paradoxieen von Russell und Burali-Forti, Abhandlungen der Fries'schen Schule, n.s. vol 2 (1908), pp 301-334.
A. Rüstow,
Der Lügner (Dissertation Erlangen 1908), Leipzig, 1910.
P. E. B. Jourdain,
Tales with philosophical morals, The Open Court, vol 27 (1913), pp. 310-315.

Parallelism: (philosophiol) A doctrine advanced to explain the relation between mind and body according to which mental processes vary concomitantly with simultineous physiological processes. This general description is applicable to all forms of the theory More strictly it assumes that for every mental change there exists a correlated neural change, and it denies any causal relation between the series of conscious processes and the series of processes of the nervous system, acknowledging, however, causation within each series. It was designed to obviate the difficulties encountered by the diverse interaction theories Moreover, no form of parallelism admits the existence of a spiritual substance of a substantial soul. Some regard consciousness as the only reality, the soul which is but an actuality, as the sum of psychic acts whose unity consists in their coherence. Others accept the teaching of the fundamental identity of mind and body, regarding the two corresponding series of psychical and physical processes as aspects of an unknown series of real processes. Thus mind and body are but appearances of a hidden underlying unity. Finally there are those who hold that the series of conscious states which constitute the mind is but an epiphenomenon, or a sort of by-product of the bodily organism. See Mind-Body Relation. -- J.J.R.
Parallelism, psychophysical: (Cr parallelos, from para, beside -- allelon, of one another). A dualistic solution of the mind body problem (see Mind-body relation) which asserts, in its extreme form, a perfect one-to-one correlation between the system of physical events in nature and the system of psychical events in mind. In its more moderate and restricted form, parallelism asserts only a correlation between all psychoses (mental events in an individual mind) and all or some neuroses (neural events in the individual's body). Thus there may exist physico-chemical and even neural processes in the body having no psychical correlates The term parallelism was introduced by Fechner (Zend-Avesta, Bk III, ch XIX, D) but the doctrine appeared in Spinoza (Ethics, Bk II, prop. 7 schol. and props. 11 and 12) -- L.W.
Paralogism: (Gr. paralogismos) A fallacious svllogism, an error in reasoning. See Sophism. -- G.R.M.

In Kant's system the paralogisms are arguments alleging to prove the substantivity, simplicity and eternality of the soul or pure ego. See Kantianism. -- O.F.K.

Paramanu: (Skr.) An exceedingly (parama) or infinitely small or magnitudeless thing (cf. anu), a discrete physical entity playing a similar role in Indian philosophy as ions, electrons, or protons in modern physics. -- K.F.L.
Paramarthika: (Skr) Relating to spiritual, essential, or absolute matters. -- A.F.L.
Parapsychology: (Gr. para, at the side or + psyche, soul + logia from logein, to speak) The investigation of prescience, telepathy and other alleged psychical phenomena which seem to elude ordinary physical and physiological explanation. The term was proposed by Boirac (1893) and was adopted by Florunay and Oesterreich. See A. Lalande, Vocabulaire de la philosophie, Vol II, p. 646. See Prescience, Telepathy. -- L.W.
Parinama-vada: (Skr.) Theory of evolution expounded by the Sankhya (q.v.), according to which the disturbed equilibrium between two primary substances (prakrti and purusa) is responsible for change. -- K.F.L.
Parmenides: 6th-5th century B.C., head of the Eleatic School of Greek Philosophy, developed the conception of "Being" in opposition to the "Becoming" of Heraclitus. To think at all we must postulate something which is, that which is not cannot be thought, and cannot be. Thought without being or being without thought are impossible, and the two are therefore identical. At the same time the "Being" of Parmenides is that which fills space, non-being is empty space Empty space therefore cannot be, and if empty space or the "Void" cannot be then the plurality of individual things is equally not real since this results from the motion of the "full" in the "void". There is thus for Parmenides only one "Being" without inner differentiation; this alone really is, while the particularity of individual things is appearance, illusion. Homogeneous and unchangeable "Being" is the only reality. -- M.F.

Parmenides' main extant work is a poem "On Truth."

Parousia: (Gr. presence) In Plato's philosophy, the presence of the Idea in the thing which, in turn, pirtakes of the Idea; in theology, the presence of Christ after his prophesied return to earth. -- K.F.L.
Parsimony, Law of: Name given to various statements of a general regulative principle of economy of thought, or effort, in the use of means to attain a purpose, like that of William of Ockham (died about 1349), called Ockham's razor: Entia non sunt multiplicanda praeter necessitatem. It is interpreted in the sense that the least possible number of assumptions are to be made in the attempt to explain ascertained facts. It has been supposed that the same principle of simplicity prevails in the physical cosmos, since apparently nature employs the fewest possible means effectively to attain the ends which are intended. -- J.J.R.
Particular: (Lat pars, a part) A member of a class as opposed to the property which defines the class; an individual as opposed to a universal. -- A.C.B.
Particular proposition: In traditional logic, propositions A, E (excepting singular forms, according to some) were called universal and I, O, particular. See Logic, formal, § 4. -- A.C.
Particulate: An adjective which means, having the form of minute particles, or assuming such a form. Also a verb now almost obsolete which signified, to divide into parts mentally, or to separate into really existing particles. Formerly it also meant, to particularize. -- J.J.R.
Parva Naturalia: The name traditionally given to a series of short treatises by Aristotle on psychological and biological topics: viz. De Sensu et Sensibili, De Memoria et Reminiscentia, De Somno, De Somniis, De Divinatione per Somnium, De Longitudine et Brevitate Vitae, De Vita et Morte, De Respiratione. -- G.R.M.
Pascal, Blaise: (1623-1662) French philosopher mathematician and scientist. He conducted scientific researches including experiments on atmospheric pressure and invented an ingenious calculating machine. He turned from preoccupation with the scientific to the study of man and his spiritual problems and found faith as a sounder guide than reason. At this stage of his thought, theology becomes central. These thoughts are developed in his Provincial Letters and in his posthumously published masterpieces of style, the Pensees. -- L.E.D.
Passive Empiricism: The doctrine that knowledge comes by way of experience with the emphasis upon the negative character of the mind. The mind can act only upon the stimulus of contact with the world outside itself. John Locke furnishes an example of this view. See Tabula rasa. -- V.F.
Past: That part of time, continuously growing, which includes all the events which have already happened. Their relationship with other past events is generally regarded as fixed. -- R.B.W.
Past-Time: All the extent of time preceding a given event or experience, the term is occasionally confined to that extent of preceding time which is relevant to a given event or experience. Obviously enough, past-time is not a permanent condition unrelated to the succession of events: anything that is past has been present and also future before it became present The ontologlcal status of the past is uncertain, insofar as it has no existence at the moment when it is called past yet cannot be designated as unconditionally non-existent in the sense applicable to fiction or untruth. -- R.B.W.
Patanjali: The author of the Yogasutras (q.v.), not identical with the famous Hindu grammarian by the same name -- K.F.L.
Patripassianism: (Lat. pater, father, patior, suffer) The teaching that God suffers. In Christian thought this view was held by Sabellius (fi. first half of third century) in connection with the sufferings of Jesus conceived to be God manifested -- V.F.
Patristic Philosophy: The advent of Christian revelation introduced a profound change in the history of philosophy. New facts about God, the world and man were juxtaposed to the conclusions of pagan philosophy, while reason was at once presented with the problem of reconciling these facts with the pagan position and the task of constructing them into a new science called theology.

In general, patristic philosophy is differentiated from medieval and modern philosophies in that it failed to distinguish adequately between the conclusions of reason and the facts of revelation. Philosophy, theology and the truths of religion made one amorphous body of truth. However, three stages mark the development of patristic thought.

(1) From dawn of Christian Era to 200: The Fathers of this period, most of them converts from paganism, proclaimed the Christian religion as "the true philosophy." Their works were mostly apologetic in nature, directed either against pagan prejudices and misconceptions or the religious speculations of Gnosticism.

(2) From 200 to circa 450: With the catechetic school of Alexandria and in particular with Clement and Origen, the work of reconciliation between Hellenistic philosophy and the Christian religion formally begins. This period is characterized by the formulation of Christian truths in the terminology and frame work of Greek thought. It ends with the gigantic synthesis of Augustine (354-430), whose fusion of Neo-Platonic thought and Christian truth molded society and furnished the tradition, culture and mental background for Christian Europe up to the end of the 14th century.

(3) From 450 to the 18th century: During this period there is a general decline until the Carlovingian renaissance. Great names are not lacking, such as those of Pseudo-Denis the Areopagite, John Damascene, Boethius and Isidore of Seville. however, the originality and spiritual elevation of an Augustine are not to be found. The period is generally characterized by the elaboration and systematization of truths already formulated. Platonic and Neo-Platonic influences predominate, though Aristotle's logic holds an honored place throughout this pre-Scholastic era. Cf. Migne's Patrologiae Latinae -- H.Gu.

Patterns of learning: Reaction modes, physiological habit systems. -- J.E.B.
Peano, Giuseppe, 1858-1932, Italian mathematician. Professor of mathematics at the University of Turin, 1890-1932. His work in mathematical logic marks a transition stage between the old algebra of logic and the newer methods. It is inferior to Frege's by present standards of rigor, but nevertheless contains important advances, among which may be mentioned the distinction between class inclusion (⊂) and class membership (∈) -- which had previously been confused -- and the introduction of a notation for formation of a class by abstraction (q. v.). His logical notations are more convenient than Frege's, and many of them are still in common use.

Peano's first publication on mathematicil logic was the introduction to his Calcolo Geometrico, 1888. His postulates for arithmetic (see arithmetic, foundations of) appeared in his Arith¦metices Principia (1889) and in revised form in Sul concetto di numero (Rivista di Matematica, vol. 1 (1891)), and were repeated in successive volumes (more properly, editions) of his Formulaire de Mathematiques (1894-1908). The last-named work, written with the aid of collaborators, was intended to provide a reduction of all mathematics to symbolic notation, and often the encyclopedic aspect was stressed as much as, or more than, that of logical analysis.

Peano is known also for other contributions to mathematics, including the discoverv of the area filling curve which bears his name, and for his advocacy of Latino sine flexione as an international language. -- A.C.

P. E. B. Jourdain,
Giuseppe Peano, The Quarterly Journal of Pure and Applied Mathematics, vol. 43 (1912), pp. 270-314.
Giuseppe Peano, supplement to Schola et Vita, Milan, 1928.
U. Cassina,
Vita et opera de Giuseppe Peano, Schola et Vita, vol. 7 (1932), pp. 117- 148.
E. Stamm,
Jozef Peano, Wiadomosci Matematyczne, vol. 36 (1933). pp. 1-56.
U. Cassina,
L'opera scientifica di Giuseppe Peano, Rendiconti del Seminario Matematico e Fisico di Milano, vol. 7 (1933), pp. 323-389.
U. Cassina,
L'oeuvre philosophique de G. Peano, Revue de Metaphysique et de Morale, vol. 40 (1933), pp. 481-491.

Peirce, Charles Sanders: American Philosopher. Born in Cambridge, Mass, on September 10th, 1839. Harvard M.A. in 1862 and Sc. B. in 1863. Except for a brief cireer as lectuier in philosophy at Harvard, 1864-65 and 1869-70 and in logic at Johns Hopkins, 1879-84, he did no formal teaching. Longest tenure was with the United States Coast and Geodetic Survey for thirty years beginning in 1861. Died at Milford, Pa. in 1914 He had completed only one work, The Grand Logic, published posthumously (Coll. Papers). Edited Studies in Logic (1883). No volumes published during his lifetime but author of many lectures, essays and reviews in periodicals, particularly in the Popular Science Monthly, 1877-78, and in The Monist, 1891-93, some of which have been reprinted in Chance, Love and Logic (1923), edited by Morris R. Cohen, and. together with the best of his other work both published and unpublished, in Collected Papers of Charles Sanders Peirce (1931-35), edited by Charles Hartshorne ¦ind Paul Weiss. He was most influenced by Kant, who had he thought, raised all the relevant philosophical problems but from whom he differed on almost every solution. He was excited by Darwin, whose doctrine of evolution coincided with his own thought, and disciplined by laboratory experience in the physical sciences which inspired his search for rigor and demonstration throughout his work. Felt himself deeply opposed to Descartes, whom he accused of being responsible for the modern form of the nominalistic error. Favorably inclined toward Duns Scotus, from whom he derived his realism. Philosophy is a sub-class of the science of discovery, in turn a branch of theoretical science. The function of philosophy is to expliin and hence show unity in the variety of the universe. All philosophy takes its start in logic, or the relations of signs to their objects, and phenomenology, or the brute experience of the objective actual world. The conclusions from these two studies meet in the three basic metaphysical categories: quality, reaction, and representation. Quality is firstness or spontaneity; reaction is secondness or actuality; and representation is thirdness or possibility. Realism (q.v.) is explicit in the distinction of the modes of being actuality as the field of reactions, possibility as the field of quality (or values) and representation (or relations). He was much concerned to establish the realism of scientific method: that the postulates, implications and conclusions of science are the results of inquiry yet presupposed by it. He was responsible for pragmatism as a method of philosophy that the sum of the practical consequences which result by necessity from the truth of an intellectual conception constitutes the entire meaning of that conception. Author of the ethical principle that the limited duration of all finite things logically demands the identification of one's interests with those of an unlimited community of persons and things. In his cosmology the flux of actuality left to itself develops those systematic characteristics which are usually associated with the realm of possibility. There is a logical continuity to chance events which through indefinite repetition beget order, as illustrated in the tendency of all things to acquire habits. The desire of all things to come together in this certain order renders love a kind of evolutionary force. Exerted a strong influence both on the American pragmatist, William James (1842-1910), the instrumentalist, John Dewey (1859-), as well as on the idealist, Jociah Royce (1855-1916), and many others. -- J.K.F.
Peirce's law: The theorem of the propositional calculus,
[[p ⊃ q] ⊃ p] ⊃ p.
-- A.C.
Pelagianism: The teaching of Pelagius of Britain who was active during the first quarter of the fifth century in Rome, North Africa, and Palestine. He denied original sin and the necessity of baptism in order to be freed from it. Death was not a punishment for sin, and men can be saved without the aid of divine grace. By justification men are purged of their sins through faith alone. Pelagius was notably influenced by Stoic doctrines. He and his followers refused to submit to the decisions of the Church, which repeatedly condemned their tenets, largely owing to the efforts of Augustine. -- J.J.R.
Perception: (Lat. perceptio, from percipere, to perceive)

(a) In contemporary psychology and epistemology: Perception is the apprehension of ordinary sense-objects, such as trees, houses, chairs, etc., on the occasion of sensory stimulation. Perception is distinguished, on the one hand, from sensation (the apprehension of isolated sense qualities) and on the other hand, from higher ideational processes of imagination, remembrance, conception and reasoning. The percept or vehicle of perception consists of actually given sense qualities supplemented by imaginatively supplied qualities which on the basis of earlier experience are ascribed to the perceived object.

(b) In early modern philosophy, perception was used in a much wider sense than (a). Thus, for Bacon, perception designated the mind's subjection to external influence and its adaptive reaction to such influence. (De Augmentis, IV, 3) Descartes and Spinoza designated by perception intellectual rather than sensuous apprehension (see Descartes, Principles, I, 32 and Spinoza's Ethics, II, prop. 40 schol. 2) and Leibniz understood by perceptions the internal state of one monad whereby it takes cognizance of other monads. Monadology, § 21. -- L.W.

Perception, non-sensory: As the opposite of imagining, it lacks the sensory content. Space and time have this characteristic as experienced by man. (Montague.) -- H.H.
Perception, pure: Is a form of action rather than a form of cognition. Involves an actual presence of external objects to the sense organs, is the reflection of the body's virtual or possible action upon these objects, or of the object's possible action upon the body. The consciousness of perception is a measure of its indetermination. (Bergson.) -- H.H.
Percepts: The abbreviation for perceptual data.
Perfectibility: The optimistic belief in the ability of man to attain an eventual complete realization of his moral possibilities. Opposed to the various philosophies and theologies of moral pessimism (e.g., the sinfulness and moral impotence of man, original sin, in Augustinianism, Lutheranism, Barthianism, et al.) -- V.F.

See Condorcet, Enlightenment.

Perfectionism: The ethical theory that perfection, our own or that of others or both, is the end at which we ought to aim, where perfection involves virtue chiefly and sometimes also the cultivation of one's talents or endowments. -- W.K.F.
Peripatetics: See Aristotelianism.
Peripety: (Gr. peripeteia) A sudden reversal of condition or fortunes, considered by Aristotle as an essential element in the plot of a tragedy. -- G.R.M.
Perry, Ralph Barton: (1876-) Professor of Philosophy at Harvard University. He was one of the founders of the new realist movement His classic biography of William James won the Pulitzer Prize for 1936. During the first World War he served as a major with the War Department Committee on Education and Special Training and this service has evidenced itself in his fervent advocacy of militant democracy. Among his works are Present Philosophical Tendencies, Philosophy of the Recent Past, General Theory of Value, 1926; Thought and Character of Wm. James, 2 vols., 1935; Shall Not Pertsh From the Earth, 1941. See Neo-Realism. -- L.E.D.
Perseity: (Lat. per se) The condition of being per se, by itself, that is being such as it is from its very nature. Perseity must not be confused with aseity The former implies independence of a subject in which to inhere, whereas the latter demands a still higher degree of independence of any efficient or producing agency whatsoever, it is predicated of God alone. Thomas Aquinas held: Quod est per se, semper est prius eo quod est per aliud. That which exists per se is always a substance. This mode of existence is distinguished from that which is per accidens, that is something which is not essential, but only belongs to a subject more or less fortuitously. A thing is per se owing to its internal constitution, or essence, but that which is per accidens is due rather to external or non-essential reasons. Thomas Aquinas taught that that which is per accidens, non potest esse semper et in omnibus, whereas that which belongs to something per se, de necessitate et semper et inseparabiliter et inest. Duns Scotus held that per se esse may be understood in the sense of being incommunicable, incommunicabiliter esse, or per se subsistere, subsisting by itself, not by another. In human acts that which is directly intended is per se, while that which is per accidens is praeter intentionem. Rational beings tend toward the good, or that which is regarded as good. If the good is intended for itself it is bonum per se, otherwise it is a bonum per accidens or secundum quid, that is relatively good. -- J.J.R.
Persian Philosophy: Persia was a vast empire before the time of Alexander the Great, embracing not only most of the orientnl tribes of Western Asia but also the Greeks of Asia Minor, the Jews and the Egyptians. If we concentrate on the central section of Persia, three philosophic periods may be distinguished
  1. Zoroastrianism (including Mithraism and Magianism),
  2. Manichaeanism, and
  3. medieval Persian thought.
Zarathustra (Or. Zoroaster) lived before 600 B.C. and wrote the Avesta, apparently in the Zend language. It is primarily religious, but the teaching that there are two ultimate principles of reality, Ormazd, the God of Light and Goodness, and Ahriman, God of Evil and Darkness, is of philosophic importance. They are eternally fighting Mitra is the intermediary between Ormazd and man. In the third century A. D., Mani of Ecbatana (in Media) combined this dualism of eternal principles with some of the doctrines of Christianity. His seven books are now known only through second-hand reports of Mohammedan (Abu Faradj Ibn Ishaq, 10th c., and Sharastani, 12th c.) and Christian (St. Ephrem, 4th c., and Bar-Khoni, 7th c.) writers. St Augustine of Hippo (354-430 A.D.) has left several works criticizing Manichaeism, which he knew at first-hand. From the ninth century onward, many of the great Arabic philosophers are of Persian origin. Mention might be made of the epicureanism of the Rubaiyat of the Persian poet, Omar Kayyam, and the remarkable metaphysical system of Avicenna, i.e. Ibn Sina (11th c.), who was born in Persia. -- V.J.B.
Persistence: The condition of enduring in time, with or without change. -- R.B.W.
Person: (in Max Scheler) The concrete unity of acts. Individual person, and total person, with the former not occupying a preferential position. -- P.A.S.

In scholasticism: The classic definition is given by Boethius: person is an individual substance of rational nature. As individual it is material, since matter supplies the principle of individuation. The soul is not person, only the composite is. Man alone is among the material beings person, he alone having a rational nature. He is the highest of the material beings, endowed with particular dignity and rights. -- R.A.

Personal Equation:

(a) Discrepancy between the chronological measurements of different scientific observers due to their differing reaction times. The error was first discovered in astronomical measurements but is a recognized source of error in all scientific measurements.

(b) The term has been extended to include all observational error due to the intrusion of idiosyncrasies of individual observers. -- L.W.

Personal Idealism: The affirmation of reality in the person and the personal nature of the World-Ground. Synonymous with Absolutist P ersonalism. -- R.T.F.
Personal Identity: (Lat. persona) Personal identity is individual identity as possessed by a person or self. Any individual, whether an inanimate thing, a living organism or a conscious self, is identical in so far as it preserves from moment to moment a similarity of structure. Personality identity involves in addition the conscious recognition of sameness. -- L.W.
Personalism: (Lat. persona, actor's mask) A modern term applied to any philosophy which considers personality the supreme value and the key to the meaning of reality.

Typical or original Personalism was theistic, the term being first used in America (1863) by Bronson Alcott for "the doctrine that the ultimate reality of the world is a Divine Person who sustains the universe by a continuous act of creative Will." (Odell Shepard: Pedlar's Progress., p. 494.)

Theistic Personalism was given systematic form in America by Borden Parker Bowne (1847-1910) for whom it implied:

Metaphysically, the personal nature of the World Ground;

Epistemologically, a knowledge validated by the common source of thought and thing in the World Ground and mediated through personality;

Logically, the pragmatic assumption that life is superior to logical form,

Ethically, that values are real and based in the Cosmic Nature.

While the term Personalism is modern it stands for an old way of thinking which grows out of the attempt to interpret the self as a part of phenomenological experience. Personalistic elements found expression in Heraclitus' (536-470 B.C.) statement "Man's own character is his daemon" (Fr. 119), and in his assertion of the Logos as an enduring principle of permanence in a world of change. These elements are traceable likewise in the cosmogony of Anaxagoras (500-430 B.C.), who gave philosophy an anthropocentric trend by affirming that mind "regulated all things, what they were to be, what they were and what they are", the force which arranges and guides (Fr. 12) Protagoras (cir. 480-410 B.C.) emphasized the personalistic character of knowledge in the famous dictum "Man is the measure of all things."

The doctrine of the person reached its high point in Greek philosophy in Socrates (469-399 B.C.) who recognized the soul or self as the center from which sprang all man's actions.

Plato (427-347 B.C.) recognized the person in his doctrine of the soul, but turned the direction of thought toward dominance by the abstract Idea.

Aristotle (384-322 B.C.) made his contiibution by insisting that only the concrete and individual could be real.

St. Augustine (354-430 A.D.) asserted that thought, and therefore the thinker, was the most certain of all things.

To Boethius (475-525) it was given to furnish the philosophy and definition of the person that held for the Middle Ages: "A person is the individual substance of a rational nature."

The importance of the person in Scholastic thought insured the personalistic concepts until they found expression in the work of Thomas Aquinas (1225-1274).

The renewal of philosophy signalized by Descartes introduced a long line of personilistic thinkers in France who under various classifications offered the main opposition to naturalism, materialism and positivism. Among these were Geulincx (1625-1669), Occasionalism; Malebranche (1638-1715), Activism; de Lignac (1710-1769), Theistic Personalism; de Biran (1766-1824), Philosophy of Effort; Cournot (1801-1877), Probabilism, Vitalism; Ravaisson (1813-1900), Spiritual Realism; Renouvier (1815-1903), Neo criticism, Personalism; Lachelier (1832-1918), Spiritua] Realism; Boutroux (1845-1921), Philosophy of Discontinuity; Bergson (1859-1941), Philosophy of Chinge, Intuitionism.

In Germany the first use of the word pcrsonalism seems to have been by Schleiermacher (1768-1834) and later by Hans Dreyer, Troeltsch, and Rudolf Otto. Among German Personalists would be included G. H. Leibniz (1646-1716), Monadism; R. H. Lotze (1817-1881), Teleological Personalism; Rudolf Eucken (1846-1926), Theistic Personalism, Vitalism; Max Schcler (1874-1928), Phenomenological Personalism; William Stern (1871-1939), Critical Personalism, Pantheistic Personalism.

In England many Theistic Personalists have appeared since Bishop Berkeley (1710-1796), Subjectivism, Subjective Idealism; including A. C. Frazer (1819-1914); T. H. Green (1836-1882); Edward Caird (1835-1908); James Wild (1843-1925), Singularism; A. J. Balfour (1848-1930); J. Cook Wilson (1849-1915); W. R. Sorley (1855-1935). Also English were H. W. Carr (1857-1931), Monadistic Personalism; F. C. S. Schiller (1864-1937), Humanism, Personalism; J. M. E. McTaggart (1866-1925), Atheistic Personalism.

In America we have among Theistic Personalists in addition to Bowne, G. T. Ladd (1842-1921); J. W. Buckham (1864-), Mary Whiton Calkins (1863-1930), Personal Idealism, Absolutistic Personalism; G. A. Wilson (1864-1941); H. A. Youtz (1867-); R. T. Flewelling (1871-), Personal Realism; A. C. Knudson (1873-); E. S. Brightman (1884-), "The Given." Though probably rejecting the term personalism, a view of American Personalism would be incomplete without mention of W. T. Harris (1835-1909); C. W. Howison (1834-1916); Josiah Royce (1855-1916); G. T. W. Patrick (1857-); W. E. Boodin (1869-); J. A. Leighton (1870); W. E. Hocking (1873-); J. B. Pratt (1875-), Personal Realism. Among contemporary Personalists abroad mention should be made of Ph. Kohnstamm, Holland, Critical Personalism; N. Losski (1870-), Prague, Organismic Personalism; N. Berdyaev (1874-), Paris;, Maurice Blondel (1861-1939), Paris, Activism; Ch. Baudouin (1893-), Geneva; Radelescu-Motru, Bucharest. In France also should be noted the leader of the Personalistic movement which might be denominated Political Personalism, E. Mounier. -- R.T.F.

Personalism, Critical: The term used by William Stern to define his concept of person as applied to the organic whole of existence. See Pantheistic Personalism, Mono-Personalism. -- R.T.F.
Personalistics: Term used bv William Stern in psychology to indicate a study of the facts that are true of man as a meaningful living whole -- a fundamental science of the human person. The Personalist, XVIII, p 50. -- R.T.F.
Personality: The totality of mental traits characterizing an individual personality or self. See Self. -- L.W.
Personal Realism: That type of Personalism which emphasizes the metaphysical nature of personality, its continuous activity in natural phenomena, and its unanalysable or realistic character as experienced fact, the ultimate real, the object of immediate knowledge. -- R.T.V.
Perspective: (Lat. perspectus pp. of pelspicio, to look through) The determination of inclusiveness of what can be actual for any organization. The point of view of an individual on the rest of existence. (a) In epistemology: the perspective predicament, the limited though real viewpoint of the individual, the plight of being confined to the experience of only part of actuality. (b) In psychology: the perception of relative distance by means of the apparent differences in the size of objects.

In aesthetics: The sense of depth and distance in painting as in poetry. Term used also for time elapsed. -- J.K.F.

Pessimism: (Lat. pessimus, the worst) The attitude gained by reflection on life, man, and the world (psychiatrically explained as due to neurotic or other physiological conditions, economically to over-population, mechanization, rampant utilitarianism; religiously to lack of faith; etc.) which makes a person gloomy, despondent, magnifying evil and sorrow, or holding the world in contempt. Rationalizations of this attitude have been attempted before Schopenhauer (as in Hesiod, Job, among the Hindus, in Byron, Giacomo Leopardi, Heine, Musset, and others), but never with such vigor, consistency, and acumen, so that since his Welt als Wille und Vorstellung we speak of a 19th century philosophic literature of pessimism which considers this world the worst possible, holds man to be born to sorrow, and thinks it best if neither existed. Buddhism (q.v.) blames the universal existence of pain, sorrow, and death; Schopenhauer the blind, impetuous will as the very stuff life and the world are made of; E. v. Hartmann the alogical or irrational side of the ill-powerful subconscious; Oswald Spengler the Occidental tendency toward civilization and hence the impossibility of extricating ourselves from decay as the natural terminus of all organic existence. All pessimists, however, suggest compensations or remedies; thus, Buddhism looks hopefully to nirvana (q.v.), Schopenhauer to the Idea, v. Hartmann to the rational, Spengler to a rebirth through culture. See Optimism. -- K.F.L.
Petites Perceptions: (Fr. little perceptions) Term by which Leibniz designates confused and unconscious perceptions. (Cf. The Monadology Sects. 21, 23 ) The Leibnizian theory of petites perceptions anticipates the modern theory of unconscious mind See Unconscious Mind. -- L.W.
Petitio principii, or begging the question, is a fallacy involving the assumption as premisses of one or more propositions which are identical with (or in a simple fashion equivalent to) the conclusion to be proved, or which would require the conclusion for their proof, or which are stronger than the conclusion and contain it as a particular case or otherwise as an immediate consequence. There is a fallacy, however, only if the premisses assumed (without proof) are illegitimate for some other reason than merely their relation to the conclusion -- e.g., if they are not among the avowed presuppositions of the argument, or if they are not admitted by an opponent in a dispute. -- A.C.
Phala: (Ski ) "Fruit", result, effect -- K.F.L.
Phantasm: (Gr. phantasma, appearance) Term used by Hobbes to designate an image or representation directly given to the percipient. See Elements of Philosophy Concerning Body, Part IV, ch XXV. -- L.W.
Phantasy: (in Scholasticism) The internal sense perceptive of objects, even of absent objects, previously pciceived by the external sense. The phantasm is the species of the object perceived by an internal sense and retained in the phantasy. -- H.G.
Pharisaism: The most characteristic type of Palestinian Judaism at the time of Christ. This group is to be thought of as the remnant of the traditional culture of the ancient Hebrews. Scorched by the memory of the long struggle between their fathers' and other cultures which resulted in the unhappy Captivity, these descendants took on a more militant nationalism and a more rigid loyalty to traditional customs, teaching their children in schools of their own (the Synagogue) the religion of the ancient sacred covenant. Since their ways separated sharply from their brethren in the dispersion and from the less nationalistic minded at home they acquired the party name (from the second century B.C.) "Pharisees." Their leaders were devout students of the written and oral traditions which they regarded as the Divine Will (Torah). To this tradition they added detailed codes of rigorous religious living. Popular among the masses they were comparatively few in number although powerful in influence. Pharisaism was a book-centered religion, strongly monotheistic, intensely legalistic, teaching a national and social gospel of redemption by an expectant supernatural visitation. The term "Pharisaic" unfortunately has acquired a sinister meaning, probably due to certain N.T. statements linking Pharisees with hypocrites. R. T. Herford in his Pharisaism (1912) and The Pharisees (1924) has shown thit this religious party was preeminently spiritually minded even though legalistic and not sufficiently understood by Christian traditionalists. -- V.F.
Phase: (chemical, physical) A term referring to a homogeneous composition of matter, either solid, liquid, or gaseous. All three phases of a single substance may co-exist. -- W.M.M.
Phase Rule: (chemicil, physical) A relationship between the number of components (C), phases (P), and degrees of freedom (F) (variability) of a heterogeneous system with respect to pressure and temperatuie and similar intensive variables when in equilibrium: P + F = C + 2. Discovered by J. W. Gibbs (1839-1903). -- W.M.M.
Phenomena: See Appearances.
Phenomenalism: (Gr. phainomenon, from phainesthai, to appear) Theory that knowledge is limited to phenomena including (a) physical phenomena or the totality of objects of actual and possible perception and (b) mental phenomena, the totality of objects of introspection. Phenomenalism assumes two forms according as it (a) denies a reality behind the phenomena (Renouvier, Shadworth, Hodgson), or (b) expressly affirms the reality of things-in-themselves but denies their knowability (Kant, Comte, Spencer.) See Hume. -- L.W.
Phenomenal World: The world of appearance as opposed to the world as-it-is-in-itself. The only world we know, said Kant, is the world-we-know, (appearance). The real world is beyond our knowledge. -- V.F.
Phenomenological Personalism: Applied to the system of Max Scheler. -- R.T.F.
Phenomenology: Since the middle of the Eighteenth Century, "Phänomenologie," like its English equivalent, has been a name for several disciplines, an expression for various concepts. Lambert, in his Neue Organon (1764), attached the name "Phänomenologie" to the theory of the appearances fundamental to all empirical knowledge. Kant adopted the word to express a similar though more restricted sense in his Metaphysische Anfangsgründe der Naturwissenschaft (1786). On the other hand, in Hegel's Phänomenologie des Geistes (1807) the same word expresses a radically different concept. A precise counterpart of Hegel's title was employed by Hamilton to express yet another meaning. In "The Divisions of Philosophy" (Lectures on Metaphysics, 1858), after stating that "Philosophy properly so called" is "conversant about Mind," he went on to say: "If we consider the mind merely with the view of observing and generalizing the various phaenomena it reveals, . . . we have . . . one department of mental science, and this we may call the Phaenomenology of Mind." Similarly Moritz Lazarus, in his Leben der Seele (1856-57), distinguished Phänomenologie from Psychologie: The former describes the phenomena of mental life; the latter seeks their causal explanation.

Edmund Husserl (1859-1938) was the first to apply the name "Phänomenologie" to a whole philosophy. His usage, moreover, has largely determined the senses commonly attached to it and cognate words in the Twentieth Century. In his Logische Untersuchungen (1900-01), Husserl gave the name to such investigations and theories as make up most of that work and of the only published volume of his Philosophie der Arithmetik (1891). This established what was to remain the primary denotation of the term in all his later writings. On the other hand -- owing to changes in his concept of his unchanging theme -- the explicit connotation of the term, as used by him, underwent development and differentiation.

In the first edition of the Logische Untersuchungen phenomenology was defined (much as it had been by Hamilton and Lazarus) as descriptive analysis of subjective processes Erlebnisse. Thus its theme was unqualifiedly identified with what was commonly taken to be the central theme of psychology; the two disciplines were said to differ only in that psychology sets up causal or genetic laws to explain what phenomenology merely describes. Phenomenology was called "pure" so far as the phenomenologist distinguishes the subjective from the objective and refrains from looking into either the genesis of subjective phenomena or their relations to somatic and environmental circumstances. Husserl's "Prolegomena zur reinen Logik" published as the first part of the Logische Untersuchungen, had elaborated the concept of pure logic, a theoretical science independent of empirical knowledge and having a distinctive theme: the universal categorial forms exemplified in possible truths, possible facts, and their respective components. The fundamental concepts and laws of this science, Husserl maintained, are genuine only if they can be established by observing the matters to which they apply. Accordingly, to test the genuineness of logical theory, "wir wollen auf die 'Sachen selbst' zurückgehen": we will go, from our habitual empty understanding of this alleged science, back to a seeing of the logical forms themselves. But it is then the task of pure phenomenology to test the genuineness and range of this "seeing," to distinguish it from other ways of being conscious of the same or other matters. Thus, although pure phenomenology and pure logic are mutually independent disciplines with separate themes, phenomenological analysis is indispensible to the critical justification of logic. In like manner, Husserl maintained, it is necessary to the criticism of other alleged knowledge; while, in another way, its descriptions are prerequisite to explanatory psychology. However, when Husserl wrote the Logische Untersuchungen, he did not yet conceive phenomenological analysis as a method for dealing with metaphysical problems.

The most radical changes in this concept of phenomenology and its relations to other disciplines had taken place before Husserl wrote his Ideen zu einer reinen Phänomenologie und phänomenologischen Philosophie, of which the only published volume, "General Introduction to Pure Phenomenology," appeared in 1913. They resulted from a development having two main aspects.

1. Phenomenological analyses, partly summarized in the Logische Untersuchungen, had led Husserl to the view that material (generic and specific) as well as logically formal universals or essences are themselves observable, though non-individual, objects. Further analyses showed that awareness of an essence as itself presented might be based on either a clear experiencing or a clear phantasying (fictive experiencing) of an example. In either case, the evidence of the essence or eidos involves evidence of some example as ideally possible but not as actual. Consequently, a science like pure logic, whose theme includes nothing but essences and essential possibilities, -- in Husserl's later terminology, an eidetic science -- involves no assertion of actual existence. Husserl used these views to redefine phenomenology itself. The latter was now conceived explicitly as the eidetic science of the material essences exemplified in subjective processes, qua pure possibilities, and was accordingly said to be pure also in the way pure logic is pure. A large proportion of the emendations in the second edition of the Logische Untersuchungen serve to clarify this freedom of phenomenology from all presuppositions of actual individual existence -- particularly, psychic existence.

2. Under the influence of Franz Brentano (1838-1917), Husserl coined the name "Intentionalität" for what he saw is the fundamental character of subjective processes. The reflectively experienceable part of one's stream of consciousness is, on the one hand, consciousness of subjective processes as immanent in the stream itself and, on the other hand, consciousness of other objects as transcending the stieam. This character of subjective processes as consciousness of, as processes in which something is intended, is a property they have intrinsically, regardless of whether what is intended in them exists. Seeing intentionality as the fundamental attribute of subjective processes, Husseil held that phenomenology must describe them not only with respect to their immanent components but also with respect to their intended objects, as intended, in the language of his Ideen, phenomenological description must be "noematic," as well as "noetic" and "hyletic."

Every conscious process intends its objects as in a context with others, some intended as presented, others intended as to become presented if intended future consciousness takes a particular course. In other words, consciousness is always an intentional predelineating of processes in which objects will be intended, as the same or different within an all inclusive objective context: the world. A pure phenomenology should therefore describe not only paiticular intended objects but also the intended world, as intended -- as part of the "noematic-objective" sense belonging to consciousness by virtue of the latter's intrinsic intentionality. To be sure, in such noematic-objective description the phenomenologist must still disregard the actual relations of the described subjective processes to other entities in the world. But, Husserl contended, when one disregards everything except the intrinsic nature of subjective processes, one still can see their intentionality; therefore all the entities and relations from which one has abstracted can -- and should -- reappear as noematic-intentional objects, within one's isolated field. In particular, the disregarded status of the observed stream of consciousness itself, its status as related to other entities in the world, reappears -- as a noematic-objective sense which the observed consciousness intends. Moreover, as purely eidetic, phenomenology finds that the intrinsic character of any actual consciousness, as intending a world and itself as in that world, is an essentially necessary determination of any possible consciousness.

Husserl noted, however, that even when one's analyses are thus pure, both abstractively and eidetically, one naturally takes it for granted that possible consciousness is possible in some (otherwise indefinite) possible world. That is to say, besides finding "the world" as part of the intentional objective sense posited in the consciousness under investigation, the investigator continues to apprehend this consciousness as essentially worldly, even though he successfully disregards even its possible relations to other worldly objects. At this point, what Husserl considered as the philosophically decisive change in his concept of phenomenology ensues.

Before writing the Ideen, he had come to believe that, as the reflective observer of one's subjective processes, one can establish and maintain the attitude of a mere onlooker, who does not participate even in his own natural attitude of believing in a possible world and apprehending his consciousness as essentially possible in that world. If this attitude of self-restraint (epoche) is consistently maintained, one can discriminate a status of one's consciousness more fundamental than its actuality or its possibility in a world and one can see that this essential worldliness of consciousness is a reflexive consequence of its more fundamental character as consciousness of a world. One can then see, furthermore, that every intendable object is essentially, and most fundamentally, a noematic-intentional object (a phenomenon) and has its being and nature because consciousness -- regardless of the latter's secondary status as in the world -- is intrinsically an (actual or potential) intending of that object, in a certain manner, as having certain determinations. Such was Husserl's contention.

In the Ideen and in later works, Husserl applied the epithet "transcendental" to consciousness as it is aside from its (valid and necessary) self-apperception as in a world. At the same time, he restricted the term "psychic" to subjectivity (personal subjects, their streams of consciousness, etc.) in its status as worldly, animal, human subjectivity. The contrast between transcendental subjectivity and worldly being is fundamental to Husserl's mature concept of pure phenomenology and to his concept of a universal phenomenological philosophy. In the Ideen, this pure phenomenology, defined as the eidetic science of transcendental subjectivity, was contrasted with psychology, defined as the empirical science of actual subjectivity in the world. Two antitheses are involved, however eidetic versus factual, and transcendental versus psychic. Rightly, they yield a four-fold classification, which Husserl subsequently made explicit, in his Formale und Transzendentale Logik (1929), Nachwort zu meinen Ideen (1930), and Meditations Cartesiennes (1931). In these works, he spoke of psychology as including all knowledge of worldly subjectivity while, within this science, he distinguished an empirical or matter-of-fact pure psychology and an eidetic pure psychology. The former is "pure" only in the way phenomenology, as explicitly conceived in the first edition of the Logische Untersuchungen, is pure: actual psychic subjectivity is abstracted as its exclusive theme, objects intended in the investigated psychic processes are taken only as the latter's noematic-intentional objects. Such an abstractive and self-restraining attitude, Husserl believed, is necessary, if one is to isohte the psychic in its purity and yet preserve it in its full intentionality. The instituting and maintaining of such an attitude is called "psychological epoche"; its effect on the objects of psychic consciousness is called "psychological reduction." As empiricism, this pure psychology describes the experienced typical structures of psychic processes and of the typical noematic objects belonging inseparably to the latter by virtue of their intrinsic intentionality. Description of typical personalities and of their habitually intended worlds also lies within its province. Having acquired empirical knowledge of the purely psychic, one may relax one's psychological epoche and inquire into the extrapsychic circumstances under which, e.g., psychic processes of a particulai type actually occur in the world. Thus an empirical pure intentional psychology would become part of a concrete empirical science of actual psychophysical organisms.

If the psychologist, having isolated some instance of subjectivity, considers it only as a purely possible example of subjectivity in some possible world, he is effecting a further, so-called eidetic, reduction of the psychic and is in the position to develop an eidetically pure phenomenological psychology or (as Husserl also called it) an eidetic psychological phenomenology. He can discover, not merely empirical types but essential psychic possibilities, impossibilities, and necessities, in any possible world. Moieover, eidetic reduction can be performed, not only on the psychic but also on any other abstractive region of the world, e.g., the physical, the concretely psychophysical, the cultural. We can develop purely eidetic sciences of every material region (material ontologies), an eidetic science of the formally universal region, "something or other" (formal ontology, the formal logic of possible being), and finally in all-embracing science of the essential (formal and material) compossibilities and non-compossibilities in any possible concrete world. An eidetic psychological phenomenology would thus become coordinated in a universal eidetic science of worldly being.

There is yet a third kind of epohe that allegedly enables one to discriminate subjectivity qua transcendental -- by effecting yet another kind of reduction, which Husserl eventually called "transcendental-phenomenological." (In his Ideen he called it simply "phenomenological.") By refraining from participition in one's inveterate (and justifiable) natural attitude of presupposing the world and the status of one's subjectivity in the world, one can see the world (and whatever else one may intend) as fundamentally a noematic-intentional object for transcendental subjectivity -- for one's individual self, the subject whose life is one's own transcendental stream of consciousness, and for other transcendental subjects. As one can describe one's actual psychic subjectivity, so one can describe one's actual transcendental subjectivity and thus produce an empirical transcendental phenomenology. Again, as in the case of the purely psychic, so in the case of the purely transcendental, an eidetic reduction enables one to produce a purely eidetic science -- here an eidetic transcendental phenomenology, the theme of which is the absolutely universal domain of transcendental subjectivity in general, including the latter's noematic-objective sense: the entire world and all its possible variants. This eidetic transcendental phenomenology is what Husserl ordinarily meant when, in the Ideen or subsequent works, he spoke simply of "phenomenology. "

Because the difference between phenomenological pure psychology and transcendental phenomenology depends on a difference in attitude towards "the same" subject matter, their contents are widely analogous. Husserl maintained, however, that genuine philosophy is possible only as transcendental phenomenology, because it alone is knowledge of that non-worldly nucleus of subjectivity in which everything intendable as immanent or as transcendent is constituted (produced, generated) as an essentially intentional object. As envisaged in the Ideen and later works, phenomenological analysis is chiefly "transcendental-constitutional" analysis of the subjective structures in which the concrete individual world is built up as an intersubjectively valid transcendent sense for transcendental subjectivity. In the course of such analysis, every legitimate philosophical problem must find its definitive solution. From the transcendental-phenomenological standpoint, however, one traditional problem, namely the relation between what are essentially objects of consciousness and "things-in-themselves" that are not essentially objects of consciousness, is seen to be spurious. On the one hand, it is evidently false that all directly presented objects of consciousness are immanent in the mind, on the other hand, the concept of an entity that is not an intentionally constituted object of transcendental consciousness is evidently self-contradictory. This is the central thesis of what Husserl called his "transcendental-phenomenological idealism."

The diversity of concepts that Husserl himself expressed by the word "phenomenology" has been a source of diverse usages among thinkeis who came under his influence and are often referred to as "the phenomenological school." Husserl himself always meant by "phenomenology" a science of the subjective and its intended objects qua intentional; this core of sense pervades the development of his own concept of phenomenology as eidetic, transcendental, constitutive. Some thinkers, appropriating only the psychological version of this central concept, have developed a descriptive intentional psychology -- sometimes empirical, sometimes eidetic -- under the title "phenomenology." On the other hand, Husserl's broader concept of eidetic science based on seeing essences and essentially necessary relations -- especially his concept of material ontology -- has been not only adopted but made central by others, who define phenomenology accordingly. Not uncommonly, these groups reject Husserl's method of transcendental-phenomenological reduction and profess a realistic metaphysics. Finally, there are those who, emphasizing Husserl's cardinal principle that evidence -- seeing something that is itself presented -- is the only ultimate source of knowledge, conceive their phenomenology more broadly and etymologically, as explication of that which shows itself, whatever may be the latter 's nature and ontologicil status. -- D.C.

Phenomenon: (Gr. phainomenon, Ger. Phaenomenon) In Kant: Broadly, appearance or that which appears. More specifically, any presentation, cognition or experience whose form and order depends upon the synthetic forms of the sensibility and categories of the understanding. In contrast to noumenon and thing-in-itself which lie outside the conditions of possible experience, and remain, therefore, theoretically unknowable. See Kantianism and Noumenon. -- O.F.K.
Philo of Alexandria: (30 B.C.- 50 A.D.) Jewish theologian and Neo-Platonic philosopher. He held that Greek thought borrowed largely from Mosaic teachings and therefore justified his use of Greek philosophy for the purpose of interpreting Scripture in a spiritual sense. For Philo, the renunciation of self and, through the divine Logos in all men, the achievement of immediate contact with the Supreme Being, is the highest blessedness for man. -- M.F
Philosopheme: (Gr. philosophema) An apodictic syllogism (Aristotle). -- G.R.M.
Philosopher, The: Generally used name for Aristotle by medieval authors after the "reception of Aristotle" from the early 13th century onwards. In earlier writers the name may refer to any head of a school, e.g. to Abelard in the writings of his pupils. -- R.A.
Philosophes: French 18th century philosophers, e.g. Condorcet, Condillac, Rousseau, Voltaire (q.v.).
Philosopher King: In Plato's theory of the ideal state rulership would be entrusted to philosopher kings. These rulers would reach the top by sheer talent and merit after a long period of training in the school of everyday work and leadership and by a prescribed pattern of formal discipline and study. The final test of leadership lay in the ability to see the truth of the Platonic vision of a reality governed by universal ideas and ideals. -- V.F.
Philosophical Psychology: Philosophical psychology, in contrast to scientific or empirical psychology, is concerned with the more speculative and controversial issues relating to mind and consciousness which, though arising in the context of scientific psychology, have metaphysical and epistemological ramifications. The principal topics of philosophical psychology are
  1. the criteria of mentality (see Mental),
  2. the relation between mind and consciousness (see Consciousness),
  3. the existence of unconscious or subconscious mind (see Unconscious mind),
  4. the structure of the mind (see Mind-stuff Theory, Gestalt Psychology),
  5. the genesis of mind (see Mind-Dust, Emergent Mentalism),
  6. the nature of the self (see Ego, Self, Personal Identity, Soul),
  7. the mind-body relation (see Mind-Body Relation),
  8. the Freedom of the Will (see Detetminism, Freedom),
  9. psychological methodology (see Behaviorism, Introspectian),
  10. mind and cognition. See Cognition, Perception, Memory.
-- L.W.
Philosophy: (Gr. philein, to love -- sophia, wisdom) The most general science. Pythagoras is said to have called himself a lover of wisdom. But philosophy has been both the seeking of wisdom and the wisdom sought. Originally, the rational explanation of anything, the general principles under which all facts could be explained; in this sense, indistinguishable from science. Later, the science of the first principles of being; the presuppositions of ultimate reality. Now, popularly, private wisdom or consolation; technically, the science of sciences, the criticism and systematization or organization of all knowledge, drawn from empirical science, rational learning, common experience, or whatever. Philosophy includes metaphysics, or ontology and epistemology, logic, ethics, aesthetics, etc. (all of which see). -- J.K.F.

Concerning the task of philosophy. See also Science of Science, Epistemology.

Philosophy of Change: The theory that change itself is the only enduring pnnciple and therefore the fundamental reality. Applied to the views of Heraclitus, and in modern times to those of Henri Bergson. -- R.T.F.
Philosophy of Discontinuity: The theory that the principle of change is the fundamental basis of reality; that natural law is but the outward aspect of what is internally habit Being as an irreducible synthesis of possibility and action. God the Creator and Essence of things. Applied to the thought of Renouvier, Boutroux, and Lachelier. -- R.T.F.
Philosophy of Effort: The theory that in the self-consciousness of effort the person becomes one with reality. Consciousness of effort is self-consciousness. Used by Maine de Biran. -- R.T.F.
Philosophy of Mind: Philosophical theory of the nature of mind and its place in the world. See Philosophical Psychology. -- L.W.
Philosophy of Religion: An inquiry into the general subject of religion from the philosophical point of view, i.e., an inquiry employing the accepted tools of critical analysis and evaluation without a predisposition to defend or reject the claims of any particular religion. Among the specific questions considered are the nature, function and value of religion; the validity of the claims of religious knowledge; the relation of religion and ethics; the character of ideal religion; the nature of evil; the problem of theodicy; revealed versus natural religion; the problem of the human spirit (soul) and its destiny; the relation of the human to the divine as to the freedom and responsibility of the individual and the character (if any) of a divine purpose; evaluation of the claims of prophecy, mystic intuitions, special revelations, inspired utterances; the value of prayers of petition; the human hope of immortality; evaluation of institutional forms of expressions, rituals, creeds, ceremonies, rites, missionary propaganda; the meaning of human existence, the character of value, its status in the world of reality, the existence and character of deity; the nature of belief and faith, etc.

The subject of the philosophy of religion is regarded in conservative circles not as a discipline given to free philosophical inquiry but as a particular religion's philosophy. In this form it is a more or less disguised apologetics or defense of an already accepted religious faith. While the data for this subject include the so-called classical religions, philosophy of religion, in the genuinely philosophical sense, takes for its material religious expressions of all types, whether classical or not, together with all the psychological material available on the nature of the human spirit and man's whole cultural development. -- V.F.

Phoronomy: Noun derived from the Greek, phorein, used by Plato and Aristotle in the sense of motion, and nomos, law; signifies kinematics, or absolute mechanics, which deals with motion from the purely theoretical point of view. According to Kant it is that part of natural philosophy which regards motion as a pure quantum, without considering any of the qualities of the moving body. -- J.J.R.
Phronesis: (Gr. phronesis) Practical wisdom, or knowledge of the proper ends of conduct and of the means of attaining them; distinguished by Aristotle both from theoretical knowledge or science, and from technical skill. See Aristotelianism. -- G.R.M.
Physical essence: (or physical composition in Scholasticism) Consists in the composition of the parts by which that composite truly is. Of these parts, that which indifferently constitutes this or that, is called matter, as the body in man, but that which determines and perfects matter is called form, as soul. -- H.G.
Physicalism: The thesis, developed within Scientific Empiricism (q.v., , II B), that every descriptive term in the language of science (in the widest sense, including social science) is connected with terms designating observable properties of things. This connection is of such a kind that a sentence applying the term in question is intersubjectively (q.v.) confirmable by observations (see Verification). The application of physicalism to psychology is the logical basis for the method of behaviorism (q.v.). See papers by O. Neurath, R. Carnap, C. G. Hempel, in Erkenntnis, 2, 1931; 3, 1932; 4, 1934; Scientia 50, 1931; Rev. de Synthese 10, 1935; Phil. Science 3, 1936; S. S. Stevens in Psych. Bull. 36, 1939. -- R.C.
Physico-Theological Argument: Kant's (q.v.) term for the teleological proof of the existence of God. -- O.F.K.
Physico-Theology: A theology which finds corroboration in natural philosophy. A term now in general disuse. -- V.F.
Physics: (Gr. physis, nature) In Greek philosophy, one of the three branches of philosophy, Logic and Ethics being the other two among the Stoics (q.v.). In Descartes, metaphysics is the root and physics the trunk of the "tree of knowledge." Today, it is the science (overlapping chemistry, biology and human physiology) of the calculation and prediction of the phenomena of motion of microscopic or macroscopic bodies, e.g. gravitation, pressure, heat, light, sound, magnetism, electricity, radio-activity, etc. Philosophical problems arise concerning the relation of physics to biological and social phenomena, to pure mathematics, and to metaphysics. See Mechanism, Physicalism..
Physis: See Nature, Physics.
Picturesque: A modification of the beautiful in English aesthetics, 18th century. -- L.V.
Pieh Mo: Neo-Mohists; heretical Mohists. See Mo che and Chinese philosophy.
Pien: Argumentation or dialectics, which "is to make clear the distinction between right and wrong, to ascertain the principles of order and disorder, to make clear the points of similarity and difference, to examine the laws of names and actualities, to determine what is beneficial and what is harmful, and to decide what is uncertain and doubtful. It describes the ten thousand things as they are, and discusses the various opinions in their comparative merits. It uses names to specify actualities, propositions to express ideas, and explanations to set forth reasons, including or excluding according to classes." It involves seven methods: "The method of possibility is to argue from what is not exhausted. The method of hypothesis is to argue from what is not actual at present. The method of imitation is to provide a model. What is imitated is taken as the model. If the reason agrees with the model, it is correct. If it does not agree with the model, it is incorrect. This is the method of imitation. The method of comparison is to make clear about one thing by means of another. The method of parallel is to compare two propositions consistently throughout. The method of analogy says, 'You are so. Why should I not be so?" The method of induction is to grant what has not been accepted on the basis of its similarity to what has already been accepted. For example, when it is said that all the others are the same, how can I say that the others are different?" (Neo-Mohism.) -- W.T.C.
Pien: Transformation or change in process; change from ens to non-ens; gradual change. See Hua. -- W.T.C.
Pien che: Sophists or Dialecticians. See Ming chia.
Pien hua che: The evolutionary transformation, which of effortless power is the greatest. (Sophism.) -- H.H.
Pietism: In general, an emphasis upon the individual appropriation of religious truth as over against its formal acceptance. As a movement, the term refers specifically to the reaction against the cold orthodoxies within German Protestantism of the late 17th and 18th centuries. Philip Spener (1635-1705) is regarded as the father of German Pietism. Under Spener's influence August Franke (1663-1727) became one of the most vigorous champions of the movement toward a more genuine Christian living. Franke was a preacher of power and founder of charitable organizations. Spener's Pia Desideria, "The Things Religiously Desired" (1675) is regarded as the Manifesto of the movement. Pietism also carries a derogatory connotation: a person is said to be "pietistic" if the seriousness of his religious practices lead him to extremes, even to the point of asceticism and fanaticism. See Puritanism. -- V.F.
Ping t'ien hsia: World peace, the ultimate goal of Confucian moral training and education. -- W.T.C.
Pistology: A noun derived from the Greek, pistis, faith, hence in general the science of faith or religious belief. A branch of theology specially concerned with faith and its restricted scope, as distinguished from reason. -- J.J.R.
Pity: A more or less condescending feeling for other living beings in their suffering or lowly condition, condoned by those who hold to the inevitability of class differences, but condemned by those who believe in melioration or the establishment of more equitable relations and therefore substitute sympathy (q.v.). Synonymous with "having mercy" or "to spare" in the Old Testament (the Lord is "of many bowels"), Christians also are exhorted to be pitiful (e.g., 1. Pet. 3.8). Spinoza yet equates it with commiseration, but since this involves pain in addition to some good if alleviating action follows, it is to be overcome in a life dictated by reason. Except for moral theories which do not recognize feeling for other creatures as a fundamental urge pushing into action, such as utilitarianism in some of its aspects and Hinduism which adheres to the doctrine of karma (q.v.), however far apart the two are, pity may be regarded a prime ethical impulse but, due to its coldness and the possibility of calculation entering, is no longer countenanced as an essentially ethical principle in modern moral thinking. -- K.F.L.
Planck, Max: (b. 1858) A German physicist who taught at the University of Kiel and later at the University of Berlin. He is world-famous for his theory of quanta, according to which all energy travels in units comparable to atoms of matter. See Planck's constant. -- R.B.W.
Planck's constant: In quantum mechanics (q.v.), a fundamental physical constant, usually denoted by the letter h, which appears in many physical formulas. It may be defined by the law that the quantum (q.v.) of radiant energy of any frequency is equal to the frequency multiplied by h. see further Uncertainty principle. -- A.C.
Plastic: The effect of relief obtained by the nuance of light and shade. -- L.V.
Plato: (428-7 - 348-7 B.C.) Was one of the greatest of the Greek philosophers. He was born either in Athens or on the island of Aegina, and was originally known as Aristocles. Ariston, his father, traced his ancestry to the last kings of Athens. His mother, Perictione, was a descendant of the family of Solon. Plato was given the best elementary education possible and he spent eight years, from his own twentieth year to the death of Socrates, as a member of the Socratic circle. Various stories are told about his supposed masters in philosophy, and his travels in Greece, Italy, Sicily and Egypt, but all that we know for certain is that he somehow acquired a knowledge of Pythagoreanisrn, Heracleitanism, Eleaticism and othei Pre-Socratic philosophies. He founded his school of mathematics and philosophy in Athens in 387 B.C. It became known as the Academy. Here he taught with great success until his death at the age of eighty. His career as a teacher was interrupted on two occasions by trips to Sicily, where Plato tried without much success to educate and advise Dionysius the Younger. His works have been very well preserved; we have more than twenty-five authentic dialogues, certain letters, and some definitions which are probably spurious. For a list of works, bibliography and an outline of his thought, see Platonism. -- V.J.B.
Platonic Realism: See Realism.
Platonism: The philosophy of Plato marks one of the high points in the development of Greek philosophical genius Platomsm is characterised by a partial contempt for sense knowledge and empirical studies, by a high regard for mathematics and its method, by a longing for another and better world, by a frankly spiritualistic view of life, by its use of a method of discussion involving an accumulation of ever more profound insights rather than the formal logic of Aristotle, and, above all, by an unswerving faith in the capacity of the human mind to attain absolute truth and to use this truth in the rational direction of human life and affairs.

The works of Plato are chiefly in the form of dialogues, remarkable for their literary as well as for their philosophic qualities. The following list includes all the dialogues recognized as authentic by modern authorities.

Early period: Ion, Charmides, Htppias I and II (doubtful), Laches, Lysis, Euthyphro, Euthydemus, Gorgias, Protagoras, Meno, Apology, Crito, Phaedo, Menexenus.

Middle period: Symposium, Phaedrus, Republic, Theaetetus, Cratylus.

Late period: Timaeus, Critias, Sophistes, Politicus, Philebus, Parmenides, Laws, Epinomis (doubtful). Thirteen Letters have also been preserved, of which two (VII-VIII), at least, are probably authentic.

Plato's theory of knowledge can hardly be discussed apart from his theory of reality. Through sense perception man comes to know the changeable world of bodies. This is the realm of opinion (doxa), such cognition may be more or less clear but it never rises to the level of true knowledge, for its objects are impermanent and do not provide a stable foundation for science. It is through intellectual, or rational, cognition that man discovers another world, that of immutable essences, intelligible realities, Forms or Ideas. This is the level of scientific knowledge (episteme); it is reached in mathematics and especially in philosophy (Repub. VI, 510). The world of intelligible Ideas contains the ultimate realities from which the world of sensible things has been patterned. Plato experienced much difficulty in regard to the sort of existence to be attributed to his Ideas. Obviously it is not the crude existence of physical things, nor can it be merely the mental existence of logical constructs. Interpretations have varied from the theory of the Christian Fathers (which was certainly not that of Plato himself) viz , that the Ideas are exemplary Causes in God's Mind, to the suggestion of Aristotle (Metaphysics, I) that they are realized, in a sense, in the world of individual things, but are apprehended only by the intellect The Ideas appear, however, particularly in the dialogues of the middle period, to be objective essences, independent of human minds, providing not only the foundation for the truth of human knowledge but afso the ontological bases for the shadowy things of the sense world. Within the world of Forms, there is a certain hierarchy. At the top, the most noble of all, is the Idea of the Good (Repub. VII), it dominates the other Ideas and they participate in it. Beauty, symmetry and truth are high-ranking Ideas; at times they are placed almost on a par with the Good (Philebus 65; also Sympos. and Phaedrus passim). There are, below, these, other Ideas, such as those of the major virtues (wisdom, temperance, courage, justice and piety) and mathematical terms and relations, such as equality, likeness, unlikeness and proportion. Each type or class of being is represented by its perfect Form in the sphere of Ideas, there is an ideal Form of man, dog, willow tree, of every kind of natural object and even of artificial things like beds (Repub. 596). The relationship of the "many" objects, belonging to a certain class of things in the sense world, to the "One", i.e. the single Idea which is their archetype, is another great source of difficulty to Plato. Three solutions, which are not mutually exclusive, are suggested in the dialogues (1) that the many participate imperfectly in the perfect nature of their Idea, (2) that the many are made in imitation of the One, and (3) that the many are composed of a mixture of the Limit (Idea) with the Unlimited (matter).

The human soul is considered by Plato to be an immaterial agent, superior in nature to the body and somewhat hindered by the body in the performance of the higher, psychic functions of human life. The tripartite division of the soul becomes an essential teaching of Platonic psychology from the Republic onward. The rational part is highest and is pictured as the ruler of the psychological organism in the well-regulated man. Next in importance is the "spirited" element of the soul, which is the source of action and the seat of the virtue of courage. The lowest part is the concupiscent or acquisitive element, which may be brought under control by the virtue of temperancc The latter two are often combined and called irrational in contrast to the highest part. Sensation is an active function of the soul, by which the soul "feels" the objects of sense through the instrumentality of the body. Particularly in the young, sensation is a necessary prelude to the knowledge of Ideas, but the mature and developed soul must learn to rise above sense perception and must strive for a more direct intuition of intelligible essences. That the soul exists before the body (related to the Pythagorean and, possibly, Orphic doctrine of transmigration) and knows the world of Ideas immediately in this anterior condition, is the foundation of the Platonic theory of reminiscence (Meno, Phaedo, Republic, Phaedrus). Thus the soul is born with true knowledge in it, but the soul, due to the encrustation of bodily cares and interests, cannot easily recall the truths innately, and we might say now, subconsciously present in it. Sometimes sense perceptions aid the soul in the process of reminiscence, and again, as in the famous demonstration of the Pythagorean theorem by the slave boy of the Meno, the questions and suggestions of a teacher provide the necessary stimuli for recollection. The personal immortality of the soul is very clearly taught by Plato in the tale of Er (Repub. X) and, with various attempts at logical demonstration, in the Phaedo. Empirical and physiological psychology is not stressed in Platonism, but there is an approach to it in the descriptions of sense organs and their media in the Timaeus 42 ff.

The Platonic theory of education is based on a drawing out (educatio) of what is already dimly known to the learner. (Meno, Repub. II-VII, Theaetetus, Laws.) The training of the philosopher-ruler, outlined in the Republic, requires the selection of the most promising children in their infancy and a rigorous disciplining of them in gymnastic, music (in the Greek sense of literary studies), mathematics and dialectic (the study of the Ideas). This training was to continue until the students were about thirty-five years of age; then fifteen years of practical apprenticeship in the subordinate offices of the state were required; finally, at the age of fifty, the rulers were advised to return to the study of philosophy. It should be noted that this program is intended only for an intellectual elite; the military class was to undergo a shorter period of training suited to its functions, and the masses of people, engaged in production, trading, and like pursuits, were not offered any special educational schedule.

Platonism as a political philosophy finds its best known exposition in the theory of the ideal state in the Republic. There, Plato described a city in which social justice would be fully realized. Three classes of men are distinguished: the philosopher kings, apparently a very small group whose education has been alluded to above, who would be the rulers because by nature and by training they were the best men for the job. They must excel particularly in their rational abilities: their special virtue is philosophic wisdom; the soldiers, or guardians of the state, constitute the second class; their souls must be remarkable for the development of the spirited, warlike element, under the control of the virtue of courage; the lowest class is made up of the acquisitive group, the workers of every sort whose characteristic virtue is temperance. For the two upper classes, Plato suggested a form of community life which would entail the abolition of monogamous marriage, family life, and of private property. It is to be noted that this form of semi-communism was suggested for a minority of the citizens only (Repub. III and V) and it is held to be a practical impossibility in the Laws (V, 739-40), though Plato continued to think that some form of community life is theoretically best for man. In Book VIII of the Republic, we find the famous classification of five types of political organization, ranging from aristocracy which is the rule of the best men, timocracy, in which the rulers are motivated by a love of honor, oligarchy, in which the rulers seek wealth, democracy, the rule of the masses who are unfit for the task, to tyranny, which is the rule of one man who may have started as the champion of the people but who governs solely for the advancement of his own, selfish interests.

The Platonic philosophy of art and aesthetics stresses, as might be expected, the value of the reasonable imitation of Ideal realities rather than the photographic imitation of sense things and individual experiences. All beautiful things participate in the Idea of beauty (Symposium and Phaedrus). The artist is frequently described as a man carried away by his inspiration, akin to the fool; yet art requires reason and the artist must learn to contemplate the world of Ideas. Fine art is not radically distinguished from useful art. In both the Republic and the Laws, art is subordinated to the good of the state, and those forms of art which are effeminate, asocial, inimical to the morale of the citizens, are sternly excluded from the ideal state.

The ethics of Platonism is intellectualistic. While he questions (Protagoras, 323 ff.) the sophistic teaching that "virtue is knowledge", and stresses the view that the wise man must do what is right, as well as know the right, still the cumulative impetus of his many dialogues on the various virtues and the good life, tends toward the conclusion that the learned, rationally developed soul is the good soul. From this point of view, wisdom is the greatest virtue, (Repub. IV). Fortitude and temperance are necessary virtues of the lower parts of the soul and justice in the individual, as in the state, is the harmonious co-operation of all parts, under the control of reason. Of pleasures, the best are those of the intellect (Philebus); man's greatest happiness is to be found in the contemplation of the highest Ideas (Repub., 583 ff.).

In the field of the philosophy of religion, Platonism becomes obscure. There is little doubt that Plato paid only lip-service to the anthropomorphic polytheism of Athenian religion. Many of the attributes of the Idea of the Good are those of an eternal God. The Republic (Book II) pictures the Supreme Being as perfect, unchangeable and the author of truth. Similar rationalizations are found throughout the Laws. Another current of religious thought is to be found m the Timaeus, Politicus and Sophist. The story of the making of the universe and man by the Demiurgus is mythic and yet it is in many points a logical development of his theory of Ideas. The World-Maker does not create things from nothing, he fashions the world out of a pre-existing chaos of matter by introducing patterns taken from the sphere of Forms. This process of formation is also explained, in the Timaeus (54 ff), in terms of various mathematical figures. In an early period of the universe, God (Chronos) exercised a sort of Providential care over things in this world (Politicus, 269-275), but eventually man was left to his own devices. The tale of Er, at the end of the Republic, describes a judgment of souls after death, their separation into the good and the bad, and the assignment of various rewards and punishments.

-- V.J.B.

The Academy continued as a school of philosophy until closed by Justinian in 529 A.D. The early scholars (Speusippus, Xenocrates, Polemo, Crates) were not great philosophers, they adopted a Pythagorean interpretation of the Ideas and concentrated on practical, moral problems. Following the Older Academy (347-247 B.C.), the Middle and New Academies (Arcesilaus and Carneades were the principal teachers) became scepticil and eclectic. Aristotle (384-322 B.C. ) studied with Plato for twenty years and embodied many Platonic views in his own philosophy. Platonism was very highly regarded by the Christian Fathers (Ambrose, Augustine, John Damascene and Anselm of Canterbury, for instance) and it continued as the approved philosophy of the Christian Church until the 12th century. From the 3rd century on, Neo-Platonism (see Plotinism) developed the other-worldly mystical side of Plato's thought. The School of Chartres (Bernard, Thierry, Wm. of Conches, Gilbert of Poitiers) in the 12th century was a center of Christian Platonism, interested chiefly in the cosmological theory of the Timaeus. The Renaissance witnessed a revival of Platonism in the Florentine Academy (Marsilio Ficino and the two Pico della Mirandolas). In England, the Cambridge Platonists (H. More, Th. Gale, J. Norris) in the 17th century started an interest in Plato, which has not yet died out in the English Universities. Today, the ethical writings of A. E. Taylor, the theoiy of essences developed by G. Santayana, and the metaphysics of A. N. Whitehead, most nearly approach a contemporary Platonism. -- V.J.B.

Platonism, medieval: Plato's works were not accessible to the medievil writers previous to the 13th century. They possessed only part of the Timaeus in the translation and commentary by Chalcidius. Nor were they acquainted with the writings of the Neo-Platonists. They had the logical texts by Porphyrius; little besides. St. Augustine, the greatest authority in these ages, was well acquainted with the teachings of the "Academy" of his time and became a source for Neo-Platonic influences. Furthermore, there were the writings of Pseudo-Dionysius of which first Alcuin had made a rather insufficient, later Scotus Eriugena a readible translation. Scotus himself was thoroughly Neo-Platonic in his philosophy, however "Christianized" his Platonism may have been. The medieval "Platoniststs" held, among some propositions of minor importance, that universals were existent substances (Realism, q.v.), that body and soul were two independent substances, united more or less accidentally; they assumed accordingly a "plurality of forms" in one substance. Some believed that Plato had been given a peculiar insight even in the mysteries of Christian faith. Thus they went so far as to identify the anima mundi, which they believed to be a Platonic notion, with the Holy Ghost (e.g. Abelard). Even after the revival of Aristotelian philosophy, against which the "Platonists" reacted violently, Platonism, or as they afterwards preferred to call it, Augustinianism persisted in many schools, especially in those depending on the Franciscans. -- R.A.
Pleasure and pain: In philosophy these terms appear mostly in ethical discussions, where they have each two meanings not always clearly distinguished. "Pleasure" is used sometimes to refer to a certain hedonic quality of experiences, viz. pleasantness, and sometimes as a name for experiences which have that quality (here "pleasures" are "pleasant experiences" and "pleasure" is the entire class of such experiences). Mutatis mutandis, the same is true of "pain". Philosophers have given various accounts of the nature of pleasure and pain. E.g., Aristotle says that pleasure is a perfection supervening on ccrtain activities, pain the opposite. Spinoza defines pleasure as the feeling with which one passes from a lesser state of perfection to a greater, pain is the feeling with which one makes the reverse transition. Again, philosophers have raised various questions about pleasure and pain. Can they be identified with good and evil? Are our actions always determined by our own pleasure and pain actual or prospective? Can pleasures and pains be distinguished quantitatively, qualitatively? See Bentham, Epicureanism. -- W.K.F.
Pleasures of the imagination: The moderate, healthful, and agreeable stimulus to the mind, resulting (in the primary class) from the properties of greatness, novelty, and beauty (kinship, color, proportionality, etc. ) in objects actually seen; (in the secondary class) from the processes of comparison, association, and remodelling set up in the mind by the products of art or by the recollection of the beauties of nature. (Addison.) -- K.E.G.
Plekhanov, George Valentinovich: (1856-1918) Was a Russian Marxist who became the philosophical leader of the Menshevik faction of the pre-Revolutionary Russian Social Democratic Workers' Party, opposing Lenin, the leader of the Bolshevik wing. In spite of what are regarded as his political errors, such as his support of the war of 1914-1918 and his negative attitude to the Revolution of October, 1917, contemporary Soviet thinkers regard Plekhanov's works as containing valuable expositions of Marxist philosophy. Among his writings in this field are, -- J.M.S.
Pleroma: Literally the Greek term means a filling up, it was used by the Gnostics to denote the world of light, or the spiritual world of aeons full of divine life. -- J.J.R.
Plotinism: The philosophic and religious thought of Plotinus (205-270). His writings were published by Porphyry in six books of nine sections, Enneads, each. All reality consists of a series of emanations, from the One, the eternal source of all being. The first, necessary emanation is that of Nous (mind or intelligence), the second that of Psyche (soul). At the periphery of the universe is found matter. Man belongs partly in the realm of spirit and partly in the sphere of matter.

Plotinism offers a well-developed theory of sensation. The objects of sensation are of a lower order of being than the perceiving organism. The inferior cannot act upon the superior. Hence sensation is an activity of the sensory agent upon its objects. Sensation provides a direct, realistic perception of material things, but, since they are ever-changing, such knowledge is not valuable. In internal seme perception, the imagimtion also functions actively, memory is attributed to the imaginative power and it serves not only in the recall of sensory images but also in the retention of the verbal formulae in which intellectual concepts are expressed. The human soul can look either upward or downward; up to the sphere of purer spirit, or down to the evil regions of matter. Rational knowledge is a cognition of intelligible realities, or Ideas in the realm of Mind which is often referred to as Divine. The climax of knowledge consists in an intuitive and mystical union with the One; this is experienced by few.

The Idea of Beauty is one and perfect according to Plotinus. All lesser beauties, spiritual and physical, are participations in the one, supreme Beauty. The attribute of the beautiful which is most stressed is splendor, it consists of a shining-forth of the spiritual essence of the beautiful thing.

Characteristically Plotinian is the teaching that man must first turn his mind away from the inferior things of sense toward the inner reality of his own soul. He must learn to regard his soul as part of the World-Soul. He must transcend the multiple things of the realm of Mind and endeavor to achieve that communion with the One, which is his ultimate good. There is no question of personal immortality and so the goal of human life is a merging with universal Spirit. In his politics, Plotinus favored a sort of community life incorporating many of the idealistic suggestions to be found in Plato's Republic.

Plotinism is a theocentric form of thought. As reality becomes more intelligible, it becomes more spiritual and Divine. The Ideas in the sphere of Nous are Divine and in later Neo-Platonism become gods; hence the system is polytheistic.

As a school of Greek and Latin philosophers, Plotinism lasted until the fifth century. Porphyry, Apuleius, Jamblichus, Julian the Apostate, Themistius, Simplicius, Macrobius and Proclus are the most important representatives. Through St. Augustine, Dionysius the Pseudo-Areopagite, John Scotus Eriugena, and the Greek Fathers, Plotinian thought has been partly incorporated into Christian intellectualism. Nearly all prominent Arabian philosophers before Averroes are influenced by Plotinus, this is particularly true of Avicenna and Algazel. In the Jewish tradition Avicebron's Fons Vitae is built on the frame of the emanation theory. Master Eckhart and Nicholas of Cusa continue the movement. It is spiritually related to some modern anti-intellectualistic and mystical currents of thought.

-- V.J.B.
Pluralism: This is the doctrine that there is not one (Monism), not two (Dualism) but many ultimate substances. From the earliest Ionian fundamentals of air, earth, fire and water, to the hierarchy of monads of Leibniz, the many things-in-themselves of Herbart and the theory of the many that "works" in the latter day Pragmatism of James and others, we get a variety of theories that find philosophic solace in variety rather than in any knowable or unknowable one. See Dualism, Idealism, Materialism, Monism, Political Philosophy (Laski). -- L.E.D.
Plurality of causes: The doctrine according to which identical events can have two or more different causes. "It is not true that the same phenomenon is always produced by the same causes," declared J. S. Mill, author of the doctrine. Quite the contrary, "many causes may produce some kind of sensation, many causes may produce death." Mill's position was not taken in support of the doctrine of free will or of that of chance, but rather in opposition to an old contention of the physicists, among whom Newton stated that "to the same natural effect we must, as far as pssible, ascribe the same cause." The subsequent controversy has shown that Mill's position was based on the confusion between "the same phenomenon" and "the same kind of phenomena". It is doubtless true that the same kind of phenomena, say death, can be produced by many causes, but only because we take the phenomenon broadly, nevertheless, it may remain true that each particular phenomenon can be caused only by a very definite cause or by a very definite combination of causes. In other words, the broader we conceive the phenomenon, the more causes are likely to apply to it. -- R.B.W.
Plutarch of Athens: (5th century AD) Founder of Athenian Neo-Platonism, author of commentaries on Platonic and Pythagorean writings.
Plutarch of Chaeronea: (about 100 AD) Famous biographer and author of several philosophical treatises. -- M.F.

Parallel Lives; Opera moralia (tr. Bolin's Classical Libr.)-

Pneuma: (Gr. pneuma, breath) A Stoic, also Epicurean, concept signifying spirit, vital force, or creative fire in its penetration into matter. Sometimes understood as psychic energy, or distinguished as the formative fire-mind and the divinely inspired rational part of man from the more emotional, physical aspect of soul. In early Christian, particularly Gnostic philosophy, pneuma, as spirit, is differentiated from psyche, or soul. See Pneuma Hagion, the Holy Ghost. -- K.F.L.
Pneumatology: (Gr. pneuma, spirit + logos, theory) In the most general sense pneumatology is the philosophical or speculative treatment of spirits or souls, including human, divine and those intermediate between God and man. D'Alembert restricted pneumatology to human souls. Discours preliminaire de I'Encyclopedie, § 73; he considered pneumatology, logic and ethics the three branches of the philosophical science of man. The term has also been considered to exclude man and to apply only to God and the angelic hierarchy. (See article by Bersot in Franck's Dict. des Sci. Philos. ) The wide sense in which pneumatology embraces first, God, second, the angels and third, man is perhaps the most convenient and justifiable usage. -- L.W.
Poiesis: (Gr poiesis) Activity of creating or making, artistic production (Aristotle). -- G.R.M.
Poietic: Relating to production or the arts of production, e.g. poietic knowledge, as distinguished from practical and from theoretical knowledge. See Aristotelianism. -- G.R.M.
Poincare, Henri: (1854-1912) French mathematician and mathematical physicist to whom many important technical contributions are due. His thought was occupied by problems on the borderline of physics and philosophy. His views reflect the influence of positivism and seem to be closely related to pngmatism. Poincare is known also for his opposition to the logistic method in the foundations of mathematics, especially as it was advocated by Bertrand i (q.v.) and Louis Couturat, and for his proposed resolution of the logical paradoxes (q.v.) by the prohibition of impredicattve definition (q.v.). Among his books, the more influential are Science and Hypothesis, Science and Method, and Dernieres Pensees. -- R.B.W.
Point-event: A. N. Whitehead's term signifying an event with all its dimensions ideally restricted. -- R.B.W.
Poissons Law: This rule, which is also called Poisson's Law of Small Numbers, is an elaboration of Bernouilli's Theorem dealing with the difference between the actual and the most probable number of occurrences of an event. 1. In cases of Random Sampling, the Poisson Exponential Limit is used in place of the Normal Probability Function or the strict application of the Bernouilli Theorem, when considering events which happen rarely. 2. In cases of Dispersion of Statistical Ratios, a Bernouilli Distribution is used when the probability of an event is constant, and a Poisson Distribution is used when that probability is variable. In both cases, there is a maximum involved which will not be surpassed, and the values obtained by Poisson's Law are smaller than those obtained in the other cases. -- T.G.
Polarity, philosophy of: Philosophies that make the concept of polarity one of the systematic principles according to which opposites involve each other when applied to any significant realm of investigation. Polarity was one of the basic concepts in the philosophy of Cusanus and Schelling. Morris R. Cohen made use of the principle of polarity in scientific philosophy, in biology, in social and historical analysis, in law and in ethics. (Cf. Reason and Nature). -- H.H.
Political Personalism: The doctrine that the state is under obligation to provide opportunity to each citizen for the highest possible physical, mental, and spiritual development, because personality is the supreme achievement of the social order. A movement in France represented by the journal Esprit. -- R.T.F.
Political Philosophy: That branch of philosophy which deals with political life, especially with the essence, origin and value of the state. In ancient philosophy politics also embraced what we call ethics. The first and most important ancient works on Political Philosophy were Plato's Politeia (Republic) and Aristotle's Politics. The Politeia outlines the structure and functions of the ideal state. It became the pattern for all the Utopias (see Utopia) of later times. Aristotle, who considers man fundamentally a social creature i.e. a political animal, created the basis for modern theories of government, especially by his distinction of the different forms of government. Early Christianity had a rather negative attitude towards the state which found expression in St. Augustine's De Civitate Dei. The influence of this work, in which the earthly state was declared to be civitas diaboli, a state of the devil, was predominant throughout the Middle Ages. In the discussion of the relation between church and empire, the main topic of medieval political philosophy, certain authors foreshadowed modern political theories. Thomas Aquinas stressed the popular origin of royal power and the right of the people to restrict or abolish that power in case of abuse; William of Ockham and Marsiglio of Padua held similar views. Dante Alighieri was one of the first to recognize the intrinsic value of the state; he considered the world monarchy to be the only means whereby peace, justice and liberty could be secured. But it was not until the Renaissance that, due to the rediscovery of the individual and his rights and to the formation of territorial states, political philosophy began to play a major role. Niccolo Machiavelli and Jean Bodin laid the foundation for the new theories of the state by stressing its independence from any external power and its indivisible sovereignty. The theory of popular rights and of the right of resistance against tyranny was especially advocated by the "Monarchomachi" (Huguenots, such as Beza, Hotman, Languet, Danaeus, Catholics such as Boucher, Rossaeus, Mariana). Most of them used the theory of an original contract (see Social Contract) to justify limitations of monarchical power. Later, the idea of a Natural Law, independent from divine revelation (Hugo Grotius and his followers), served as an argument for liberal -- sometimes revolutionary -- tendencies. With the exception of Hobbes, who used the contract theory in his plea for absolutism, almost all the publicists of the 16th and 17th century built their liberal theories upon the idea of an original covenant by which individuals joined together and by mutual consent formed a state and placed a fiduciary trust in the supreme power (Roger Williams and John Locke). It was this contract which the Pilgrim Fathers translated into actual facts, after their arrival in America, in November, 1620, long before John Locke had developed his theorv. In the course of the 17th century in England the contract theory was generally substituted for the theory of the divine rights of kings. It was supported by the assumption of an original "State of Nature" in which all men enjoyed equal reciprocal rights. The most ardent defender of the social contract theory in the 18th century was J. J. Rousseau who deeply influenced the philosophy of the French revolution. In Rousseau's conception the idea of the sovereignty of the people took on a more democratic aspect than in 17th century English political philosophy which had been almost exclusively aristocratic in its spirit. This tendency found expression in his concept of the "general will" in the moulding of which each individual has his share. Immanuel Kant who made these concepts the basis of his political philosophy, recognized more clearly than Rousseau the fictitious character of the social contract and treated it as a "regulative idea", meant to serve as a criterion in the evaluation of any act of the state. For Hegel the state is an end in itself, the supreme realization of reason and morality. In marked opposition to this point of view, Marx and Engels, though strongly influenced by Hegel, visualized a society in which the state would gradually fade away. Most of the 19th century publicists, however, upheld the juristic theory of the state. To them the state was the only source of law and at the same time invested with absolute sovereignty: there are no limits to the legal omnipotence of the state except those which are self imposed. In opposition to this doctrine of unified state authority, a pluralistic theory of sovereignty has been advanced recently by certain authors, laying emphasis upon corporate personalities and professional groups (Duguit, Krabbe, Laski). Outspoken anti-stateism was advocated by anarchists such as Kropotkin, etc., by syndicalists and Guild socialists. -- W.E.
Politics: (Gr. polis, city) The normative science which treats of the organization of social goods. The branch of civics concerned with government and state affairs. See Political Philosophy. -- J.K.F.
Polysyllogism: A chain of syllogisms arranged to lead to a single final conclusion, the conclusion of each syllogism except the last serving as premiss of a later syllogism.

In contrast, an argument consisting of a single syllogism is called a monosyllogism. -- A.C.

Polytheism: (Gr. polus, many; and theos, god) A theory that Divine reality is numerically multiple, that there are many gods, opposed to monotheism. See Plotinism. -- V.J.B.
Pompanazzi, Pietro or Pereto: (1462-1524) Was born in Mantua, in Italy, and studied medicine and philosophy at Padua. He taught philosophy at Padua, Ferrara and Bologna. He is best known for his Tractatus de immortalitate animae (ed. C. G. Bardili, Tübingen, 1791) in which he denied that Aristotle taught the personal immortality of the human soul. His interpretation of Aristotle follows that of the Greek commentntor, Alexander of Aphrodisias (3rd c. A.D.) and is also closelv related to the Averroistic tradition. -- V.J.B.
Pons asinorum: The literal meaning of the Latin expression, asses' bridge, has been figuratively applied to a diagram constructed by Petrus Tartaretus about 1480, whose purpose was to aid the student of logic in finding the middle term of a syllogism and disclose its relations. It was assumed that it was as difficult to persuade students to do this as to get asses to pass over a bridge. Hence the expression has also been applied to any relatively easy test. Euclids proposition, that if two sides of a triangle are equal the angles opposite to those sides must also be equal, has been called a pons asinorum for students of geometry -- J.J.R.
Porphyry: (c. 232-304 B.C.) A disciple of Plotinus, who adapted Aristotelian logic to Neo-Platonic philosophy. His method of classification by means of dichotomy is known as the "Tree of Porphyry" (q.v.). Cf. Isagoge (tr. by Boethius, q.v.). -- R.B.W.
Port Royal Logic: See Logic, traditional.
Port Royalists: Name applied to a group of thinkers, writers, and educators, more or less closely connected with the celebrated Cistercian Abbey of Port Royal near Paris, which during the seventeenth century became the most active center of Jansenism and, to a certain extent, of Cartesianism in France. The Port Royalists were distinguished by the severity and austerity of their moral code and by their new educational methods which greatly promoted the advance of pedagogy. The most noted among them were Jean Duvergier de Hauranne, abbot of Saint Cyran (1581-1643), Antoine-le grand Arnauld (1612-1694), and Pierre Nicole (1625-1695). Cf. Sainte-Beuve, Port-Royal. -- J.J.R.
Posidonius of Rhodes: (c. 135-50 B.C.) An eclectic philosopher of the Stoic School, who incorporated into his thought many doctrines of Plato and Aristotle. -- R.B.W.
Posit: (Lat. ponere, to put or place) (a) In logic and epistemology, positing is the act of entertaining or asserting a proposition immediately i.e. without recourse to inference. A proposition may be posited either because it is regarded as (1) a self-evident truth or (2) a postulate arbitrarily assumed. The postulational sense of positing is the more common at present. See Postulate.

(b) In idealistic metaphysics: positing, in the philosophy of G. Fichte is the initial act by which the Ego creates itself: "The positing of the Ego through itself is therefore, the pure activity of the Ego." (Fichte, The Science of Knowledge, Trans, by A. F. Kroeger, p. 68.) -- L.W.

Positional: The characters of perception are positional. The positional character of the thought is the idea. (Avenarius.) -- H.H.
Positionality: (Ger. Positionalität) In Husserl: The character common to conscious processes of positing or setting an object, whether believingly, or in valuing or willing. Doxic positionality is common to processes involving belief, disbelief, doubt, etc.. (see Doxa), axiological positionality, to processes of loving, hating, or otherwise valuing; volitional, to those involving inclination, disinclination, voluntary doing, etc. Positionality in all its forms is contrasted with quasi-positionality (see Phantasy) and neutrality. -- D.C.
Positive Theology: A term referring to doctrines alleged to be grounded upon a "positive" revelation and not upon the alleged "negative" conclusions of liberal and rationalistic speculations. The term was used to characterize Scriptural theologies from the freer deistic and rationalistic expositions of doctrines, also, it was used to oppose the conclusions of the so-called "higher critics" of the New and Old Testaments. The term has still another meaning: a theology is said to be positive if it is "constructive", by which is meant that it is apologetic of the spirit, if not the letter, of Protestant faith. In the latter sense positive theology is said to be distinguished from a philosophical theology. -- V.F.
Positivism: First associated with the doctrine of Auguste Comte that the highest form of knowledge is simple description presumably of sensory phenomena. The doctrine was based on an evolutionary "law of three stages", believed by Comte to have been discovered by him in 1822 but anticipated by Turgot in 1750. The three stages were the theological, in which anthropomorphic wills were resorted to to explain natural events, the metaphysical, in which these wills were depersonalized and became forces and essences, and finally the positive. It should be noted that positivistic description was supposed to result in mathematical formulas, not in introspective psychology. See Scientific Empiricism I. -- G.B.

In legal philosophy (q.v.): That trend in Legal Philosophy which confines itself to positive law i.e. the law that actually is valid in a certain country at a certain time. It excludes any higher law such as natural law, sometimes even any evaluation of positive law. The Allgemeine Rechtslehre (general theory of law) in Germany, analytical jurisprudence in England, the "pure theory of law" and American legal realism are types of legal positivism. See Legal Philosophy. -- W.E.

Possibility: According to distinctions of modality (q. v.), a proposition is possible if its negation is not necessary. The word possible is also used in reference to a state of knowledge rather than to modality, as a speaker might say, "It is possible that 486763 is a prime number," meaning that he had no information to the contrary (although this proposition is impossible in the sense of modality).

A propositional function F may also be said to be possible. In this case the meaning may be either simply (Ex)F(x); or that (Ex)F(x) is possible in one of the senses just described; or that F(x) is permitted under some particulai system of conventions or code of laws. As an example of the last we may take "It is possible for a woman to be President of the United States." Here F is λx[x is a woman and x is a President of the United States], and the code of laws in question is the Constitution of the United States. -- A.C.

Possible: (Gr. endechomenon) According to Aristotle that which happens usually but not necessanly, hence distinguished both from the necessary and from the impossible. -- G.R.M.
Post hoc, ergo propter hoc: (Lat. after this, therefore on account of this) A logical fallacy in which it is argued that a consequent is caused by an antecedent, simply because of the temporal relationship. -- V.J.B.
Postpredicament: Noun generally applied since the time of Abelard to any particular one of the five conceptions, or relations, examined in detail in the tenth and following chapters of the treatise on the Categories, or Predicaments, ascribed to Aristotle, which, however, was very probably written by others after his death. -- J.J.R.
Postulate: (Lat. postulatum; Ger. Postulat) In Kant (1) An indemonstrable practical or moral hypothesis, such as the reality of God, freedom, or immortality, belief in which is necessary for the performance of our moral duty. (2) Any of three principles of the general category of modality, called by Kant "postulates of empirical thought." See Modality and Kantianism. -- O.F.K.
Postulate: See Mathematics.
Potency: (Scholastic) Potency is opposed to act as asserted of being. It means the capacity of being or of being thus. Prime matter (q.v.) is pure potency, indetermined in regard to actual corporeal being. Any change or development or, generally, becoming presupposes a corresponding potency. Some potencies belong to the nature of a thing, others are merely passive and consist in non-repugnance. Thus to be thrown is not due to a potency strictly speaking in the stone which has, in regard to this a "merely obediential" potency. The first kind is also called operative potency. -- R.A.
Potentiality: See Dynamis.
Power: In general:
  1. the physical, mental and moral ability to act or to receive an action;
  2. the general faculty of doing, making, performing, realizing, achieving, producing or succeeding;
  3. ability, capacity, virtue, virtuality, potency, potentiality, faculty, efficacy, efficacity, efficiency, operative causality, process of change or becoming;
  4. natural operative force, energy, vigor, strength, or effective condition applied or applicable to work;
  5. person, agent, body, institution, government or state, having or exercising an ability to act in accordance with its nature and functions;
  6. spirit, divinity, deity, superhuman agent, supernatural principle of activity;
  7. an attribute or name of God;
  8. in theology, an order of angels;
  9. in law the authority, capacity or right to exercise certain natural and legal prerogatives, also, the authority vestcd in a person by law;
  10. influence, prerogative, force.

A. In psychology, power is sometimes synonymous with faculty (q.v.). It also means a quality which renders the nature of an individual agent apt to elicit certain physical and moral actions. Hence, power is a natural endowment enabling the intellect to condition the will and thus create hibits and virtues, in a higher degree, power is a moral disposition enabling the individual to cultivate his perfectibility. The distinction between powers is given by the distinction of their actions. Powers are acthe or operative, and passive or receptive; they are immediate or remote. Even impotence and incapacity are not different in kind from power, but simply in degree. These Aristotelian views on power, including its ontological interpretation, have held the ground for centuries, and we find them partly also in Hobbes and Locke who defined power as the ability to make or to receive change. Hume's analysis of power showed it to be an illusion; and with the advent of positivism and experimental psychology, this concept lost much of its value. The notion of power has been used by Fechner in his doctrine and law concerning the relation between stimuli and sensations.

B. In ontology, power is often synonymous with potency (q.v.) Aristotle, who is mainly responsible for the development of this notion (Metaph. IV (5) 12.), distinguishes three aspects of it as a source of change, as a capacity of performing, and as a state in virtue of which things are unchangeable by themselves. Hobbes accepts only the first of these meanings, namely that power is the source of motion. Various questions are involved in the analysis of the notion of power, as, for example, whether power is an accident or a perfection of substance, and whether it is distinct from it.

C. In natural philosophy, power corresponds to effort, to the force applied to overcome resistance. More technically, it is the time rate of the performance of work, or the transfer of energy. In optics, power is the degree to which an optical instrument magnifies.

D. In mathematics, (1) it is a numerical or algebraical index showing the number of times the element it affects must be multiplied by itself; concurrently, it denotes the product arising from the continued mutiplication of a quantity by itself. (2) In the theory of aggregates, the power of a class is the number of its elements, its cardinal number (q.v.). -- T.G.

Practical: (Ger. praktisch) In Husserl: Of or pertaining to such conscious processes as reach fulfilment in behavior. -- D.C.
Practical: Relating to praxis, or conduct. -- G.R.M.
Practical Imperative: (in Kant's ethics) Kant's famous dictum: "So act as to treat humanity, whether in thine own person or in that of any other, in every case as an end withal, never as means only." -- P.A.S.
Practical Reason: (Kant. Ger. praktische Vernunft) Reason or reflective thought concerned with the issues of voluntary decision and action. Practical reason includes "everything which is possible by or through freedom." In general, practical reason deals with the problems of ethics. Kant asserted the primacy of practical reason over theoretical reason, and also asserted as practical postulates (q.v.) certain conceptions which were not theoretically demonstrable. See Kantianism. -- O.F.K.
Practical Theology: A special department of conventional theological study, called "practical" to distinguish it from general theology, Biblical, historical and systematic studies. As the term denotes, subjects which deal with the application of the theoretical phases of the subject come under this division: church policy (ccclesiology), the work of the minister in worship (lituigics and hymnology), in preaching (homiletics), in teaching (catechetics), in pastoral service (poimenics), and in missionary effort (evangelistics). For further discussion see Theological Propaedeutic (9th ed., 1912), Philip Schaff. -- V.F.
Practice: (Lat. practice, business) The deliberate application of a theory. Formerly, an established custom; the pursuance of some traditional action. Now, the organization of actuality according to some general principle. Sometimes, opposed to, sometimes correlative with, theory (q.v.). -- J.K.F.
Praedicabilia: (Lat. that which is able to be predicated) Since Greek philosophic thinking, the modes of predicating or the concepts to be affirmed of any subject whatsoever, usually enumerated as five: genus, species, difference, property (or, characteristic), and accident. They assumed an important role in the scholastic discussions of universals. According to Kant, they are pure, yet derived concepts of the understanding. -- K.F.L.
Praedicamenta: (Scholastic) The ten praedicaments are, according to Aristotle (Met. V.) and the Schoolmen substance, quantity, quality, relation, habitus, when, where, location, action, passion. -- R.A.
Pragmatic theory of truth: Theory of knowledge which maintains that the truth of a proposition is determined by its practical consequences. See Pragmatism. -- A.C.B.
Pragmatic Realism: The doctrine that knowledge comes by way of action, that to know is to act by hypotheses which result in successful adaption or resolve practical difficulties. According to pragmatic realism, the mind is not outside the realm of nature; in experience the organism and the world are at one; the theories of knowledge which follow the alleged dualism between the objective and subjective worlds are false. Ideas and knowledge are instruments for activity and not spectators of an outside realm. -- V.F.
Pragmaticism: Pragmatism in Peirce's sense. The name adopted in 1905 by Charles S. Peirce (1893-1914) for the doctrine of pragmatism (q.v.) which had been enunciated by him in 1878. Peirce's definition was as follows: "In order to ascertain the meaning of an intellectual conception one should consider what practical consequences might conceivably result by necessity from the truth of that conception, and the sum of these consequences will constitute the entire meaning of the conception". According to Peirce, W. James had interpreted pragmatism to mean "that the end of man is action", whereas Peirce intended his doctrine as "a theory of logical analysis, or true definition," and held that "its merits are greatest in its application to the highest metaphysical conceptions". "If one can define accurately all the conceivable experimental phenomena which the affirmation or denial of a concept could imply, one will have therein a complete definition of the concept, and there is absolutely nothing more in it". Peirce hoped that the suffix, -icism, might mark his more strictly defined acception of the doctrine of pragmatism, and thus help to distinguish it from the extremes to which it had been pushed by the efforts of James, Schiller, Papini, and others. -- J.K.F.
Pragmatics: The study of the relations between signs and their interpreters in abstraction from relations to their designata or to other signs. A department of Semiotic (q.v.). -- M.B.
Pragmatism: (Gr. pragma, things done) Owes its inception as a movement of philosophy to C. S. Peirce and William James, but approximations to it can be found in many earlier thinkers, including (according to Peirce and James) Socrates and Aristotle, Berkeley and Hume. Concerning a closer precursor, Shadworth Hodgson, James says that he "keeps insisting that realities are only what they are 'known as' ". Kant actually uses the word "pragmatic" to characterize "counsels of prudence" as distinct from "rules of skill" and "commands of morality" (Fundamental Principles of the Metaphysic of Morals, p. 40). His principle of the primacy of practical reason is also an anticipation of pragmatism. It was reflection on Kant's Critique of Pure Reason which originally led Peirce to formulate the view that the muddles of metaphysics can be cleared up if one attends to the practical consequences of ideas. The pragmatic maxim was first stated by Peirce in 1878 (Popular Science Monthly) "Consider what effects, that might conceivably have practical bearings, we conceive the object of our conception to have. Then, our conception of these effects is the whole of our conception of the object". A clearer formulation by the same author reads: "In order to ascertain the meaning of an intellectual conception one should consider what practical consequences might conceivably result by necessity from the truth of that conception, and the sum of these consequences will constitute the entire meaning of the conception". This is often expressed briefly, viz.: The meaning of a proposition is its logical (or physical) consequences. The principle is not merely logical. It is also admonitory in Baconian style "Pragmatism is the principle that everv theoretical judgment expressible in a sentence in the indicative mood is a confused form of thought whose onlv meaning, if it has any, lies in its tendency to enforce a corresponding practical maxim expressible as a conditional sentence having its apodosis in the impentive mood". (Collected Papers of Charles Sanders Peirce, edited by Charles Hartshorne and Paul Weiss, 5.18.) Although Peirce's maxim has been an inspiration not only to later pragmatists, but to operationalists as well, Peirce felt that it might easily be misapplied, so as to eliminate important doctrines of science -- doctrines, presumably, which hive no ascertainable practical consequences.

James' definition of pragmatism, written for Baldwin's Dictionary of Philosophy, is simply a restatement, or "exegesis", of Peirce's definition (see first definition listed above) appearing in the same place. The resemblance between their positions is illustrated by their common insistence upon the feasibility and desirability of resolving metaphysical problems by practical distinctions, unprejudiced by dogmatic presuppositions, their willingness to put every question to the test. "The pragmatic method", says James, "tries to interpret each notion by tracing its respective practical consequences. . . . If no practical difference whatever can be traced", between two alternatives, they "mean practically the same thing, and all dispute is idle". (Pragmatism, p. 45. See also Chapters III and IV.)

But while Peirce thought of pragmatism as akin to the mathematical method, James' motivation and interest was largely moral and religious. Thus in his Will to Believe (New World, 1896) he argues, in line with Pascal's wager, that "we have the right to believe at our own risk any hypothesis that is live enough to tempt our will," i.e. if it is not resolvable intellectually. Speaking of religious scepticism, he says. "We cannot escape the issue by remaining sceptical . . . because, although we do avoid error in that way if religion be untrue, we lose the good, if it be true, just as certainly as if we positively choose to disbelieve". The position of the religious skeptic is: ''Better risk loss of truth than chance of error, . . ." Later, in 1907 in the Lowell Lectures he stated that "on pragmatistic principles, if the hypothesis of God works satisfactorily in the widest sense of the word, it is true", and took a position between absolutism and materialism which he called "pragmatistic or melioristic" theism. In the same lectures he announces that " 'the true', to put it briefly, is only the expedient in the way of thinking, . . ." James also identifies truth with verifiability, thus anticipating both the experimentalism of Dewey and the operationalism of Bridgman and the logical positivists.

Pragmatism is first and always a doctrine of meaning, and often a definition of truth as well, but as to the latter, not all pragmatists are in complete agreement. Neither Peirce nor Dewey, for example, would accept James' view that if the hypothesis of God works satisfactorily for the individual, it is true. Pragmatism is also a method of interpreting ideas in terms of their consequences. James, however, apparently does not believe that this method entails his specific philosophical doctrines -- his pluralism, individualism, neutralism, indeterminism, meliorism, pragmatic theism, "crass" supernaturalism, etc. In fact, he states that pragmatism is independent of his new philosophy of "radical empiricism" and agrees with the anti-intellectualist bent of the Italian pragmatist, Papini, who sees the pragmatic method available to the atheist, the praying penitent, the investigating chemist, the metaphysician and the anti-metaphysician ("What Pragmatism Means".) On the other hand, insofar as pragmatism is practically identified with the scientific method (as is allegedly the case with Dewey) it appears that the pragmatic method might be expected to yield much the same conclusions for one philosopher as for another. In general, pragmatism as a method, does not seem to imply any final philosophical conclusions. It may imply a general direction of thought, such as empiricism. Although pragmatists (Peirce, James, Dewey) frequently attack older forms of empiricism, or crude empiricism, and necessarily reject truth as a simple or static correspondence of propositions with sense data, they nevertheless continue to describe themselves as empiricists, so that today pragmatism (especially in Dewey's case) is often regarded as synonymous with empiricism. See Empiricism.

F. C. S. Schiller, the Oxford pragmatist or humanist, is, if anything, more hostile to rationalism, intellectualism, absolute metaphysics and even systematic and rigorous thinking than James himself. In his Humanism (1903) and his most important book Studies in Humanism (1907), he attempts to resolve or deflate metaphysical issues and controversies by practical distinctions of terms and appeal to personal, human factors, supposedly forgotten by other philosophers. Schiller wrote about many of the topics which James treated: absolute metaphysics, religion, truth, freedom, psychic research, etc., and the outcome is similar. His spirited defense of Protagoras, "the humanist", against Socrates and his tireless bantering critique of all phases of formal logic are elements of novelty. So also is his extreme activism. He goes so far as to say that "In validating our claims to 'truth' . . . we really transform them [realities] by our cognitive efforts, thereby proving our desires and ideas to be real forces in the shaping of the world". (Studies tn Humanism, 1906, p. 425.) Schiller's apparent view that desires and ideas can transform both truth and reality, even without manipulation or experiment, could also be found in James, but is absent in Dewey and later pragmatists.

John Dewey prefers to call his philosophy experimentalism, or even instrumentalism, but the public continues to regard him as the leading exponent of pragmatism. Dewey's pragmatism (like that of Peirce and James), is (1) a theory of meaning, and of truth or "warranted assertibihty", and (2) a body of fairly flexible philosophical doctrines. The connection between (1) and (2) requires analysis. Joseph Ratner (editor of volumes of Dewey's philosophy), claims that if Dewey's analysis of experimentalism is accepted almost everything that is fundamental in his philosophy follows (Intelligence in the Modern World, John Dewey's Philosophy, ed. Joseph Ratner, N. Y., 1939), but on the other hand it might also be claimed that Dewey's method, whatever name is given to it, can be practiced by philosophers who have important doctrinal differences.

In Reconstruction in Philosophy (New York, 1920, p. 156), Dewey states "When the claim or pretension or plan is acted upon it guides us truly or falsely; it leads us to our end or away from it. Its active, dynamic function is the all-important thing about it, and in the quality of activity induced by it lies all its truth and falsity. The hypothesis that works is the true one, and truth is an abstract noun applied to the collection of cases, actual, foreseen and desired, that receive confirmation in their work and consequences". The needs and desires which truth must satisfy, however, are not conceived as personal and emotional (as with James) but rather as "public" in some not altogether explicit sense. Although Dewey emphasizes the functional role of propositions and laws (and even of sensations, facts and objects), and describes these materials of knowledge as means, tools, instruments or operations for the transformation of an indeterminate situation into a determinate one in the process of inquiry (Logic, The Theory of Inquiry, N. Y., 1938), he does not clearly deny that they have a strictly cognitive role as well, and he once states that "the essence of pragmatic instrumentalism is to conceive of both knowledge and practice as means of making goods -- excellencies of all kinds -- secure in experienced existence". (The Quest for Certainty, N. Y., 1929, p. 37.) Indeed, in his Logic (p. 345), he quotes with approval Peirce's definition "truth is that concordance of an abstract statement with the ideal limit towards which endless inquiry would tend to bring scientific belief, . . ." Here truth seems to be represented as progressive approximation to reality, but usually it is interpreted as efficacy, verification or practical expediency.

Experimentalism: Since Dewey holds that "experimentation enters into the determination of every warranted proposition" (Logic, p. 461), he tends to view the process of inquiry as experimentation. Causal propositions, for example, become prospective, heuristic, teleological; not retrospective, revelatory or ontological. Laws are predictions of future occurrences provided certain operations are carried out. Experimentalism, however, is sometimes interpreted in the wider Baconian sense as an admonition to submit ideas to tests, whatever these may be. If this is done, pseudo-problems (such as common epistemological questions) either evaporate or are quickly resolved.

Operationalism: Scientific propositions are, roughly speaking, predictions and a prediction is an if-then proposition: "If certain operations are performed, then certain phenomena having determinate properties will be observed. Its hypothetical character shows that it is not final or complete but intermediate and instrumental" (Logic, p. 456). P. W. Bridgman's very influential formulation of operationalism is comparable: "In general, we mean by any concept nothing more than a set of operations, the concept is synonymous with the corresponding set of operations". (The Logic of Modern Physics, p. 5.) If the operation is (or can be), carried out the proposition has meaning, if the consequences which it forecasts occur, it is true, has "warranted assertibility" or probability.

The question of whether the operations must be specified or merely conceivable for the proposition to have meaning (which is analogous to the constructibility problem in mathematical discussions) has occasioned considerable criticism, for there appeared to be a danger that important scientific propositions might be excluded as meaningless. To this and other problems of operationalism the logical positivists (or empiricists) have contributed formulary modifications and refinements. See Logical Empiricism. In spite of their frequent difference with regard to the empirical foundation of logic and mathematics, pragmatism has received some support from the strict logicians and mathematical philosophers. One of the most important instances historically was C. I. Lewis' paper "The Pragmatic Element in Knowledge" (University of California Publications in Philosophy, 1926). Here he stated 'that the truth of experience must always be relative to our chosen conceptual systems", and that our choice between conceptual systems "will be determined consciously or not, on pragmatic grounds".

Instrumentalism: In the philosophy of Dewey, instrumentahsm is scarcely distinguishable from experimentalism or operationahsm although it is used to characterize his earlier philosophy, and is, in its associations, more closely related to evolutionary philosophy, and nore influenced by biological, than by physical or social science.

On the continent of Europe philosophers as far removed from Dewey as Hans Vaihinger are sometimes called pragmatists (Ueberweg). The similarities are of doubtful importance. -- V.J.M.

Prajapati: (Skr.) "Lord of creatures", originally applied to various Vedic (q.v.) gods, it assumed as early as the Rig Veda the importance of a first philosophical principle of creation, and later of time as suggestive of gestation and productive periodicity. -- K.F.L.
Prajna: (Skr.) Realization, insight into the true and abiding nature of the self, atman, purusa, etc. -- K.F.L.
Prajnana: (Skr.) Intelligence. -- K.F.L.
Prakrti: (Skr.) Primary matter or substance, nature, with purusa (q.v.) one of the two eternal bases of the world according to the Sankhya and the Yogasutras. It is the unconscious yet subtle cause of all material phenomena having three gunas (q.v.), sativa, rajas, tamas. Modifications of this view may be met throughout Indian philosophy. -- K.F.L.
Prama: (Skr.) In its philosophical sense equivalent to pramana (q.v.). -- K.F.L.
Pramana: (Skr. measure) A standard of action or reasoning; knowledge as such or as a logical criterion having validity; a mode of proof, a criterion of truth, such as authority, perception, inference, customarily acknowledged at the outset by all Indian philosophic systems, according to predelection. -- K.F.L.
Prameya: (Skr. to be measured, measurable) The proposition or thing to be proved; the object of knowledge. -- K.F.L.
Prana: (Skr.) Originally meaning "breath", the word figures in early Indian philosophy as "vital air" and "life" itself. Subspecies of it are also recognized, such as apana, udana, etc. -- K.F.L.
Pranayama: (Skr.) Breath (prana) exercise considered, like asana (q.v.), a necessary accessory to proper functioning of mind, manas (q.v.). -- K.F.L.
Prasada: (Skr. inclining towards) Favor, grace, recognized by some Indian religio-metaphysical systems as divine recompense for bhakti (q.v.). -- K.F.L.
Pratyabhijna: (Skr.) "Recognition", particularly the rediscovery or realization that the divine and ultimate reality is within the human soul or self. One phase of the philosophy of the Trika (q.v.). -- K.F.L.
Pratyahara: (Skr.) Withdrawal of the senses from external objects, one of the psycho-physical means for attaining the object of Yoga (q. v.). For the theory of the senses conceived as powers, see Indriya. -- K.F.L.
Pratyaksa: (Skr.) Perception, evidence of the senses. -- K.F.L.
Praxis: (Gr. praxis) Activity that has its goal within itself; conduct, distinguished from poiesis, or production, which aims at bringing into existence something distinct from the activity itself. -- G.R.M.
Preception: (Lat. prae + perceptio, a taking) The anticipatory representation of an object which guides and facilitates the perception of it. -- L.W.
Pre-critical: This adjective is commonly applied to all Kant's works prior to the Critique of Pure Reason since they all dogmatically assume knowledge of things-in-themselves to be possible. It is also applied to the sections of the Critique which are thought to have been written earliest, whether or not they imply this assumption. See Kantianism. -- A.C.E.
Predestination: The doctrine that all events of man's life, even one's eternal destiny, are determined beforehand by Deity. Sometimes this destiny is thought of in terms of an encompassing Fate or Luck (Roman and Greek), sometimes as the cyclic routine of the wheel of Fortune (Indian), sometimes as due to special gods or goddesses (Clotho, Lachesis and Atropos in Hesiod), sometimes as the Kismet or mysterious Fate (Mohammedanism), as due to rational Necessity (Stoicism) and more often in terms of the sheer will of a sovereign Deity (Hebrew, Jewish and Christian). In historic Christianity utterances of Paul are given as the authority for the doctrine (Eph. 1:11, Rom. 8:30, Rom. 9:18). St. Augustine believed that man's own sinfulness made his salvation utterly dependent upon the sheer grace and election of God. Extreme expressions of Calvinism and Lutheranism held that man does absolutely nothing toward his salvation apart from the grace and good will of the Divine. Classical examples of theological determinism are the views of Bucer (1491-1551), Calvin (see Calvinism), and the American theologian, Jonathan Edwards (1703-1758). The two classic theories concerning the place of the alleged Fall of man are supralapsarianism, the view that the Fall itself was predetermined; infralapsarianism, the view that man's predestination was set up subsequent to the Fall, the Fall itself only being permitted. -- V.F.
Predetermination: Purpose set up beforehand. -- V.F.
Predicables: (Lat. praedicabilia) In Aristotle's logic the five types of predicates that may be affirmed or denied of a subject in a logical proposition, viz. definition, genus, differentia, property, and accident. The list of predicables as formulated by Porphyry and later logicians omits definition and includes species. See Definition: Genus; Species; Differentia; Property; Accident. -- G.R.M.
Predicament: (Ger. from Lat. praedicamentum, a category) The Kantian name for the innate a priori forms of the understanding, since each category is a way of predicating something of a subject, and since there are twelve types of judgment, Kant enumerated twelve praedicaments: totality, plurality, unity, reality, negation, limitation, substantiality-inherence, causality-dependence, reciprocity, possibility-impossibility, being and non-being, necessity-contingency. -- V.J.B.
Predicate: The four traditional kinds of categorical propositions (see Logic, formal, § 4) are: all S is P, no S is P, some S is P, some S is not P. In each of these the concept denoted by S is the subject and that denoted by P is the predicate.

Hilbert and Ackermann use the word predicate for a propositional function of one or more variables, Carnap uses it for the corresponding syntactical entity, the name or designation of such a propositional function (i.e., of a property or relation). -- A.C.

Preformationism: (Lat. pre + formare, to form before) The doctrine, according to which, the organs and hereditary characters of living creatures are already contained in the germ either structurally or by subsequent differentiation. Cf. Leibniz (q.v.) (Monadology, sect. 74) who was influenced by Leeuwenhoek's microscopic discoveries and theory of the homunculus (little human contained in the sperm).

1. The process and the expression of an inference made with respect to a future event.

2. According to Plato, a prophetic prediction is a form of inspired "frenzy" which produces a good result which could not be obtained in a normal state of mind (Phaedrus). The other two forms of this abnormal activity are poetic inspiration and religious exaltation. This concept has been exalted by Christian theology which gave to it a divine origin: the gift of prediction is an attribute of a saint, and also of the biblical prophets.

3. In mathematical theory, prediction is an inference regarding an unknown or future event, from calculations involving probabilities and in particular the computation of correlations. Statistical predictions are usually made by means of regression coefficients and regression lines, which indicate the amount of change of one variable which accompanies a given amount of change in the other variable. The process of predicting values within the range of known data is called interpolation, and the process of predicting values beyond the range of known data is called extrapolation. The reliability of these predictions varies on the basis of the known variables, and of their limits. -- T.G.

Preestablished Harmony: A theory expounded by Leibniz and adopted in modified form by other thinkers after him, to refute the theories of interactionism, occasionalism, and the parallel ism of the Spinozistic type, in psycho-physics. According to its dynamism, matter and spirit, body and soul, the physical and the moral, each a "windowless", perfect monad (q.v.) in itself, are once and for all not only corresponding realities, but they are also synchronized by God in their changes like two clocks, thus rendering the assumption of any mutual or other influences nugatory. -- K.F.L.
Prehension: (Lat. prehensus, from prehendere, to seize) In the terminology of A. N. Whitehead, prehension is the process of feeling whereby data are grasped or prehended by a subject. See Process and Reality, Part III -- L.W.
Prehension, Span of: The maximum number of items or groups of items which an individual mind is capable of embracing within the unity of attention. See J. Ward, Psychological Principles, pp. 222 ff. See Attention, Span of. -- L.W.
Prehistory: That part of history of which we have no written records, documents or oral accounts, but which is reconstructed from material remains by archeologists and anthropologists.
Premiss: A proposition, or one of several propositions, from which an inference is drawn, or the sentence expressing such a proposition. Following C. S. Peirce, we here prefer the spelling premiss, to distinguish from the word premise in other senses (in particular to distinguish the plural from the legal term premises). -- A.C.
Prenex normal form: See Logic, formal, §3.
Prescience: Supposedly direct acquaintance with the future in contrast to fore-knowledge which is usually considered to be descriptive and inferential (see Fore-Knowledge) Prescience is usually attributed only to God. -- L.W.
Present: That momentary and transient part of time in which all events and experiences take place. Is usually conceived as having no duration ("knife-edge") or small duration ("saddleback"). -- R.B.W.
Presentation: (Lat. praesentatio, a showing, representation) (a) In the narrow sense anything directly present to a knowing mind such as sense data, images of memory and imagination, emotional and hedonic states, etc. See Datum. (b) In the wider sense any object known by acquaintance rather than by description for example, an object of perception or memory. See Acquaintance, Knowledge by. -- L.W.
Presentational continuum: (Lat. praesentare, to present) The conception of an individual mind as an originally undifferentiated continuum which becomes progressively differentiated in the course of experience. See article Psychology by J. Ward in Encyclopaedia Britannica, 9th ed., also J. Ward Psychological Principles, Ch. IV. -- L.W.
Presentational Immediacy: (Lat. praesens ppr. of praeesse, and in + medius, middle) Presentational immediacy characterizes any items which are in the direct cognitive presence of the mind such as sense data, images, emotional and affective data. Immediacy is ascribed by some epistemologists to higher levels of knowledge, e.g. perception and memory and by the mystic to the knowledge of God. -- L.W.
Presentationism: The epistemological theory that the mind is in perception and perhaps also memory and other types of cognition directly aware of its object (see Epistemological Monism). Although the term is ordinarily applied to realistic theories of perception (see Epistemological Realism, Naive Realism), it is equally applicable to idealistic and phenomenalistic theories (see Epistemological Idealism). Presentationism, whether realistic or idealistic, is opposed to representationalism. See Representationalism. -- L.W.
  1. That which must antecedently be assumed if a desired result is to be derived, thus, a postulate
  2. That which is logically necessaiy, thus, that which is implied, an implicate.
  3. That which is causally necessary, thus a condition or result.
-- C.A.B.
Prevarication: A deviation from truth or fact; an evasion or equivocation, a quibble, a lie. -- C.A.B.
Prima facie duties: A phrase used by W. D. Ross to indicate the nature of the general material rules of duty which he regarded as self-evident. Promise-keeping is a prima facie duty, one among others. I.e., if I have made a promise, I have a prima facie duty to keep it, which means that I will have an actual duty to keep it, if no higher prima facie duty is incumbent upon me. What Ross calls "prima facie duties" H. A. Prichard calls "claims" and E. F. Carntt "responsibilities." The notion is central to the recent neo-intuitionism of Oxford, constituting its reply to the usual objection to intuited general material propositions about duty on the score that these may conflict and must admit of exceptions. -- W.K.F.
Primary Qualities: The inherent qualities of bodies solidity, extension, figure, motion, rest, number. These qualities are conceived to be utterly inseparable from objects, they are constant. John Locke made classic the distinction of primary and secondary qualities made by Galileo and Descartes. -- V.F.
Primary truth: (Lat. primus, first) A conception or proposition which is dependent for its truth on no other principle in the same order of thought, it may be considered self-evident from common experience, special intuitive insight, or even by postulation, but it is not demonstrated -- V.J.B.
Prime Matter: See Matter.
Prime Mover: In Aristotle's philosophy that which is the first cause of all change and, being first, is not subject to change by any prior agent. See Aristotelianism. -- G.R.M.
Primitive Communism: That stage of primitive society in which there is some form of socialized ownership of the basic means of production (the land, fisheries, natural resources and the like), an absence of economic classes (q.v.) and of the state as a special apparatus of internal force. -- J.M.S.
Primitivism: A modern term for a complex of ideas running back in classical thought to Hesiod. Two species of primitivism are found, (1) chronological primitivism, a belief that the best period of history was the earliest; (2) cultural primitivism, a belief that the acquisitions of civilization are evil. Each of these species is found in two forms, hard and soft. The hard primitivist believes the best state of mankind to approach the ascetic life; man's power of endurance is eulogized. The soft primitivist, while frequently emphasizing the simplicity of what he imagines to be primitive life, nevertheless accentuates its gentleness. The Noble Savage is a fair example of a hard primitive; the Golden Race of Hesiod of a soft. -- G.B.

Cf. Studies in Primitivism, ed. Lovejoy and Boas.

Primum cognitum: (Lat. primus, first, cognitus pp. of cognoscere, to know) In Scholastic philosophy the most primitive intellectual cognition of the mind, in contrast to mere sensible cognition. -- L.W.
Principium individuationis: (Lat.) Principle of individuation (q.v.); the intrinsic, real factor in an existing singular thing which causes the individuality of the thing. -- V.J.B.
Principle: (Lat. principe, from principium, a beginning) A fundamental cause or universal truth, that which is inherent in anything. That which ultimately accounts for being. According to Aristotle, the primary source of all being, actuality and knowledge. (a) In ontology: first principles are the categories or postulates of ontology. (b) In epistemology: as the essence of being, the ground of all knowledge. Syn. with essence, universal, cause. -- J.K.F.
Principle of non-sufficient reason: According to this law, the probabilities of two propositions may be said to be equal, if there is no adequate ground for declaring them unequal. When applied without qualification, this principle may lead to unwarranted results. Such a difficulty may be avoided by an adequate formulation of the Principle of Indifference. -- T.G.
Principle of Organic Unities: A principle enunciated by G. E. Moore to the effect that the intrinsic value of a whole need not be equal to the sum of the intrinsic values of its parts. See Intrinsic value. -- W.K.F.
Principle of sufficient reason: According to Leibniz, one of the two principles on which reasoning is founded, the other being the principle of Contradiction. While the latter is the ground of all necessary truths, the Principle of Sufficient Reason is the ground of all contingent and factual truths. It applies especially to existents, possible or factual, hence its two forms actual sufficient reasons, like the actual volitions of God or of the free creatures, are those determined by the perception of the good and exhibit themselves as final causes involving the good, and possible sufficient reasons are involved, for example, in the perception of evil as a possible aim to achieve. Leibniz defines the Principle of Sufficient Reason as follows: It is the principle "in virtue of which we judge that no fact can be found true or existent, no judgment veritable, unless there is a sufficient reason why it should be so and not otherwise, although these reasons cannot more than often be known to us. . . . There must be a sufficient reason for contingent truths or truths of fact, that is, for the sequence of things which are dispersed throughout the universe of created beings, in which the resolution into particular reasons might go into endless detail" (Monadology, 31, 32, 33, 36). And again, "Nothing happens without a sufficient reason; that is nothing happens without its being possible for one who should know things sufficiently to give a reason showing why things are so and not otherwise" (Principles of Nature and of Grace). It seems that the account given by Leibniz of this principle is not satisfactory in itself, in spite of the wide use he made of it in his philosophy. Many of his disciples vainly attempted to reduce it to the Principle of Contradiction. See Wolff.

2. Kant also developed the Leibnizian principles with some modifications in his early writing Principiorum Primorum Cognitionis Metaphysicae Nova Dilucidatio (1755), where the Principle of Sufficient Reason becomes the Principle of Determining Reason (Ratio Determinans). Two forms of this principle are distinguished by Kant the ratio cur or antecedenter determinans identified with the ratio essendi vel fiendi, and the ratio quod or consequenter determinans identified with the ratio cognoscendi. It has been defended under these forms against Crusius and the argument that it destroys human freedom. -- T.G.

Principal coordination: (Ger. prinzipialkoordination) The ego and the environment are the two central links in the originally given. The restoration of the natural world conception in which the perceived environmental fragments are no more viewed as ideas in us. It forms the correlative functioning of object and subject. (Avenarius.) -- H.H.
Priority: The condition of being earlier in a succession of events. This condition is meaningful only in the past-present-future series relative to a given event or experience. In its logical sense, the term signifies a condition without which something else cannot be understood, explained, or thought of. -- R.B.W.
Privacy, Epistemic: (Lat. privatus, from privus, private) Status of data of knowledge, e.g. somatic sensations, hedonic and emotional states, and perhaps even sense data, in so far as they are directly accessible to a single knowing subject. See Publicity, Epistemic. -- L.W.
Privation: (Lat. privatis) In Aristotle's philosophy the condition of a substance that lacks a certain quality which it is capable of possessing and normally does possess. -- G.R.M
Proaeresis: (Gr. proairesis) Reflective choice, especially of means to an end, deliberate desire (Aristotle). -- G.K.M.
Probabilism: The doctrine of the ancient Skeptics that certainty is unattainable, and that probability is the only guide to belief and action, especially characteristic of the New Academy. See Petrce. -- G.R.M.
Probability: In general
  1. Chance, possibility, contingency, likelihood, likehness, presumption. conjecture, prediction, forecast, credibility, relevance;
  2. the quality or state of being likely true or likely to happen;
  3. a fact or a statement which is likely true, real, operative or provable by future events;
  4. the conditioning of partial or approximate belief or assent;
  5. the motive of a presumption or prediction;
  6. the conjunction of reasonable grounds for presuming the truth of a statement or the occurrence of an event;
  7. the field of knowledge between complete ignorance and full certitude;
  8. an approximation to fact or truth;
  9. a qualitative or numerical value attached to a probable inference, and
  10. by extension, the systematic study of chances or relative possibilities as forming the subject of the theory of probability.

A. The Foundation of Probability. We cannot know everything completely and with certainty. Yet we desire to think and to act as correctly as possible hence the necessity of considering methods leading to reasonable approximations, and of estimating their results in terms of the relative evidence available in each case. In D VI-VII (infra) only, is probability interpreted as a property of events or occurrences as such: whether necessary or contingent, facts are simply conditioned by other facts, and have neither an intelligence nor a will to realize their certainty or their probability. In other views, probability requires ultimately a mind to perceive it as such it arises from the combination of our partial ignorance of the extremely complex nature and conditions of the phenomena, with the inadequacy of our means of observation, experimentation and analysis, however searching and provisionally satisfactory. Thus it may be said that probability exists formally in the mind and materially in the phenomena as related between themselves. In stressing the one or the other of these two aspects, we obtain (1) subjectize probability, when the psychological conditions of the mind cause it to evaluate a fact or statement with fear of possible error; and (2) objective probability, when reference is made to that quality of facts and statements, which causes the mind to estimate them with a conscious possibility of error. Usually, methods can be devised to objectify technically the subjective aspect of probability, such as the rules for the elimination of the personal equation of the inquirer. Hence the methods established for the study and the interpretation of chances can be considered independently of the state of mind as such of the inquirer. These methods make use of rational or empirical elements. In the first case, we are dealing with a priori or theoretical probability, which considers the conditions or occurrences of an event hypothetically and independently of any direct experience. In the second case, we are dealing with inductive or empirical probability. And when these probabilities are represented with numerals or functions to denote measures of likelihood, we are concerned with quantitative or mathematical probability. Methods involving the former cannot be assimilated with methods involving the latter, but both can be logically correlated on the strength of the general principle of explanation, that similar conjunctions of moral or physical facts demand a general law governing and justifying them.

B. The Probability-Relation. Considering the general grounds of probability, it is pertinent to analyze the proper characteristics of this concept and the valid conditions of its use in inferential processes. Probability presents itself as a special relation between the premisses and the conclusion of an argument, namely when the premisses are true but not completely sufficient to condition the truth of the conclusion. A probable inference must however be logical, even though its result is not certain, for its premisses must be a true sign of its conclusion. The probability-relation may take three aspects: it is inductive, probable or presumptive. In strict induction, there is an essential connection between the facts expressed in the premisses and in the conclusion, which almost forces a factual result from the circumstances of the predication. This type of probability-relation is prominent in induction proper and in statistics. In strict probability, there is a logical connection between the premisses and the conclusion which does not entail a definite factual value for the latter. This type of probability-relation is prominent in mathematical probability and circumstantial evidence. In strict presumption, there is a similarity of characteristics between the fact expressed in the conclusion and the real event if it does or did exist. This type of probability-relation is prominent in analogy and testimony. A presumptive conclusion should be accepted provisionally, and it should have definite consequences capable of being tested. The results of an inductive inference and of a probable inference may often be brought closer together when covering the same field, as the relations involved are fundamental enough for the purpose. This may be done by a qualitative analysis of their implications, or by a quantitative comparison of their elements, as it is done for example in the methods of correlation. But a presumptive inference cannot be reduced to either of the other two forms without losing its identity, because the connection between its elements is of an indefinite character. It may be said that inductive and probable inferences have an intrinsic reasonableness, while presumptive inferences have an extrinsic reasonableness. The former involve determinism within certain limits, while the latter display indeterminacy more prominently. That is why very poor, misleading or wrong conclusions are obtained when mathematical methods are applied to moral acts, judiciary decisions or indirect testimony The activity of the human will has an intricate complexity and variability not easily subjected to calculation. Hence the degree of probability of a presumptive inference can be estimated only by the character and circumstances of its suggested explanation. In moral cases, the discussion and application of the probability-relation leads to the consideration of the doctrines of Probabilism and Probabiliorism which are qualitative. The probability-relation as such has the following general implications which are compatible with its three different aspects, and which may serve as general inferential principle:

  1. Any generalization must be probable upon propositions entailing its exemplification in particular cases;
  2. Any generalization or system of generalizations forming a theory, must be probable upon propositions following from it by implication;
  3. The probability of a given proposition on the basis of other propositions constituting its evidence, is the degree of logical conclusiveness of this evidence with respect to the given proposition;
  4. The empirical probability (p = S/E) of a statement S increases as verifications accrue to the evidence E, provided the evidence is taken as a whole; and
  5. Numerical probabilities may be assigned to facts or statements only when the evidence includes statistical data or other numerical information which can be treated by the methods of mathematical probability.

C. Mathematical Probability. The mathematical theory of probability, which is also called the theory of chances or the theory of relative possibilities, is concerned with the application of mathematical methods to the determination of the likelihood of any event, when there are not sufficient data to determine with certainty its occurrence or failure. As Laplace remarked, it is nothing more than common sense reduced to calculation. But its range goes far beyond that of common sense for it has not only conditioned the growth of various branches of mathematics, such as the theory of errors, the calculus of variations and mathematical statistics, but it has also made possible the establishment of a number of theories in the natural and social sciences, by its actual applications to concrete problems. A distinction is usually made between direct and inverse probability. The determination of a direct or a priori probability involves an inference from given situations or sets of possibilities numerically characterized, to future events related with them. By definition, the direct probability of the occurrence of any particular form of an event, is the ratio of the number of ways in which that form might occur, to the whole number of ways in which the event may occur, all these forms being equiprobable or equally likely. The basic principles referring to a priori probabilities are derived from the analysis of the various logical alternatives involved in any hypothetical questions such as the following: (a) To determine whether a cause, whose exact nature is or is not known, will prove operative or not in certain circumstances; (b) To determine how often an event happens or fails. The comparison of the number of occurrences with that of the failures of an event, considered in simple or complex circumstances, affords a baisis for several cases of probable inference. Thus, theorems may be established to deal with the probability of success and the probability of failure of an event, with the probability of the joint occurrence of several events, with the probability of the alternative occurrence of several events, with the different conditions of frequency of occurrence of an event; with mathematical expectation, and with similar questions. The determination of an a posteriori or inverse probability involves an inference from given situations or events, to past conditions or causes which rnay have contributed to their occurrence. By definition, an inverse probability is the numerical value assigned to each one of a number of possible causes of an actual event that has already occurred; or more generally, it is the numerical value assigned to hypotheses which attempt to explain actual events or circumstances. If an event has occurred as a result of any one of n several causes, the probability that C was the actual cause is Pp/E (Pnpn), when P is the probability that the event could be produced by C if present, and p the probability that C was present before the occurrence of that event. Inverse probability is based on general and special assumptions which cannot always be properly stated, and as there are many different sets of such assumptions, there cannot be a coercive reason for making a definite choice. In particular, the condition of the equiprobability of causes is seldom if ever fulfilled. The distinction between the two kinds of probability, which has led to some confusion in interpreting their grounds and their relations, can be technically ignored now as a result of the adoption of a statistical basis for measuring probabilities. In particular, it is the statistical treatment of correlation which led to the study of probabilities of concurrent phenomena irrespective of their direction in time. This distinction may be retained, howe\er, for the purpose of a general exposition of the subject. Thus, a number of probability theorems are obtained by using various cases of direct and inverse probability involving permutations and combinations, the binomial theorem, the theory of series, and the methods of integration. In turn, these theurems can be applied to concrete cases of the various sciences.

D. Interpretations of Probability. The methods and results of mathematical probability (and of probability in general) are the subject of much controversy as regards their interpretation and value. Among the various theories proposed, we shall consider the following

  1. Probability as a measure of belief,
  2. probability as the relative frequency of events,
  3. probability as the truth-frequency of types of argument,
  4. probability as a primitive notion,
  5. probability as an operational concept,
  6. probability as a limit of frequencies, and
  7. probability as a physical magnitude determined by axioms.

I. Probability as a Measure of Belief: According to this theory, probability is the measure or relative degree of rational credence to be attached to facts or statements on the strength of valid motives. This type of probability is sometimes difficult to estimate, as it may be qualitative as well as quantitative. When considered in its mathematical aspects, the measure of probable inference depends on the preponderance or failure of operative causes or observed occurrences of the case under investigation. This conception involves axioms leading to the classic rule of Laplace, namely: The measure of probability of any one of mutually exclusive and apriori equiprobable possibilities, is the ratio of the number of favorable possibilities to the total number of possibilities. In probability operations, this rule is taken as the definition of direct probability for those cases where it is applicable. The main objections against this interpretation are:

  1. that probability is largely subjective, or at least independent of direct experience;
  2. that equiprobability is taken as an apriori notion, although the ways of asserting it are empirical;
  3. that the conditions of valid equiprobability are not stated definitely;
  4. that equiprobability is difficult to determine actually in all cases;
  5. that it is difficult to attach an adequate probability to a complex event from the mere knowledge of the probabilities of its component parts, and
  6. that the notion of probability is not general, as it does not cover such cases as the inductive derivation of probabilities from statistical data.

II. Probability as a Relative Frequency. This interpretation is based on the nature of events, and not on any subjective considerations. It deals with the rate with which an event will occur in a class of events. Hence, it considers probability as the ratio of frequency of true results to true conditions, and it gives as its measure the relative frequency leading from true conditions to true results. What is meant when a set of calculations predict that an experiment will yield a result A with probability P, is that the relative frequency of A is expected to approximate the number P in a long series of such experiments. This conception seems to be more concerned with empirical probabilities, because the calculations assumed are mostly based on statistical data or material assumptions suggested by past experiments. It is valuable in so far as it satisfies the practical necessity of considering probability aggregates in such problems. The main objections against this interpretation are:

  1. that it does not seem capable of expressing satisfactorily what is meant by the probability of an event being true;
  2. that its conclusions are more or less probable, owing to the difficulty of defining a proper standard for comparing ratios;
  3. that neither its rational nor its statistical evidence is made clear;
  4. that the degree of relevance of that evidence is not properly determined, on account of the theoretical indefinite ness of both the true numerical value of the probability and of the evidence assumed, and
  5. that it is operational in form only, but not in fact, because it involves the infinite without proper limitations.

III. Probability as Truth-Frequency of Types of Arguments: In this interpretation, which is due mainly to Peirce and Venn, probability is shifted from the events to the propositions about them; instead of considering types and classes of events, it considers types and classes of propositions. Probability is thus the ability to give an objective reading to the relative tiuth of propositions dealing with singular events. This ability can be used successfully in interpreting definite and indefinite numerical probabilities, by taking statistical evaluations and making appropriate verbal changes in their formulation. Once assessed, the relative truth of the propositions considered can be communicated to facts expressed by these propositions. But neither the propositions nor the facts as such have a probability in themselves. With these assumptions, a proposition has a degree of probability, only if it is considered as a member of a class of propositions; and that degree is expressed by the proportion of true propositions to the total number of propositions in the class. Hence, probability is the ratio of true propositions to all the propositions of the class examined, if the class is finite, or to all the propositions of the same type in the long run, if the class is infinite. In the first case, fair sampling may cover the restrictions of a finite class; in the second case, the use of infinite series offers a practical limitation for the evidence considered. But in both cases, probability varies with the class or type chosen, and probability-inferences are limited by convention to those cases where numerical values can be assigned to the ratios considered. It will be observed that this interpretation of probability is similar to the relative frequency theory. The difference between these two theories is more formal than material in both cases the probability refers ultimately to kinds of evidence based on objective matter of fact. Hence the Truth-Frequency theory is open to the sime objections as the Relative-Frequency theory, with proper adjustments. An additional difficulty of this theory is that the pragmatic interpretation of truth it involves, has yet to be proved, and the situation is anything but improved by assimilating truth with probability.

IV. Probability as a Primitive Notion: According to this interpretation, whicn is due particularly to Keynes, probability is taken as ultimate or undefined, and it is made known through its essential characteristics. Thus, probability is neither an intrinsic property of propositions like truth, nor an empty concept, but a relative property linking a proposition with its partial evidence. It follows that the probability of the same proposition varies with the evidence presented, and that even though a proposition may turn out to be false, our judgment that it is probable upon a given evidence can be correct. Further, since probability belongs to a proposition only in its relation to other propositions, probability-inferences cannot be the same as truth-inferences as they cannot break the chain of relations between their premisses, they lack one of the essential features usually ascribed to inference. That is why, in particular, the conclusions of the natural sciences cannot be separated from their evidence, as it may be the case with the deductive sciences. With such assumptions, probability is the group name given to the processes which strengthen or increase the likelihood of an analogy. The main objection to this interpretation is the arbitrary character of its primitive idea. There is no reason why there are relations between propositions such that p is probable upon q, even on the assumption of the relative character of probability. There must be conditions determining which propositions are probable upon others. Hence we must look beyond the primitive idea itself and place the ground of probability elsewhere.

V. Probability as an Operattonal Concept: In this interpretation, which is due particularly to Kemble, probability is discussed in terms of the mental operations involved in determining it numerically. It is pointed out that probability enters the postulates of physical theories as a useful word employed to indicate the manner in which results of theoretical calculations are to be compared with experimental data. But beyond the usefulness of this word, there must be a more fundamental concept justifying it; this is called primary probability which should be reached by an instrumentalist procedure. The analogy of the thermometer, which connects a qualitative sensation with a number, gives an indication for such a procedure. The expectation of the repetition of an event is an elementary form of belief which can be strengthened by additional evidence. In collecting such evidence, a selection is naturally made, by accepting the relevant data and rejecting the others. When the selected data form a pattern which does not involve the event as such or its negative, the event is considered as probable. The rules of collecting the data and of comparing them with the theoretical event and its negative, involve the idea ol correspondence which leads to the use of numbers for its expression. Thus, probability is a number computed from empirical data according to given rules, and used as a metric and a corrective to the sense of expectation, and the ultimate value of the theory of probability is its service as a guide to action. The main interest of this theory lies in its psychological analysis and its attempt to unify the various conceptions of probability. But it is not yet complete; and until its epistemological implications are made clear, its apparent eclecticism may cover many of the difficulties it wishes to avoid. -- T.G.

VI. Probability as a Limit of Frequencies. According to this view, developed especially by Mises and by Wald, the probability of an event is equal to its total frequency, that is to the limit, if it exists, of the frequency of that event in n trials, when n tends to infinity. The difficulty of working out this conception led Mises to propose the notion of a collective in an attempt to evolve conditions for a true random sequence. A collective is a random sequence of supposed results of trials when (1) the total frequency of the event in the sequence exists, and (2) the same property holds with the same limiting value when the sequence is replaced by any sequence derived from it. Various methods were devised by Copeland, Reichenbach and others to avoid objections to the second condition: they were generalized by Wald who restricted the choice of the "laws of selection" defining the ranks of the trials forming one of the derived sequences, by his postulate that these laws must form a denumerable set. This modification gives logical consistency to this theory at the expense of its original simplicity, but without disposing of some fundamental shortcomings. Thus, the probability of an event in a collective remains a relative notion, since it must be known to which denumerable set of laws of selection it has been defined relatively, in order to determine its meaning, even though its value is not relative to the set. Controversial points about the axiomatization of this theory show the possibility of other alternatives.

VII. Probability as a Physical Magnitude determined by Axioms.. This theory, which is favoured mainly by the Intuitionist school of mathematics, considers probability as a physical constant of which frequencies are measures. Thus, any frequency is an approximate measure of one physical constant attached to an event and to a set of trials: this constant is the probability of that event over the set of trials. As the observed frequencies differ little for large numbers of trials from their corresponding probabilities, some obvious properties of frequencies may be extended to probabilities. This is done without proceeding to the limit, but through general approximation as in the case of physical magnitudes. These properties are not constructed (as in the axiomatization of Mises), but simply described as such, they form a set of axioms defining probability. The classical postulates involved in the treatises of Laplace, Bertrand or Poincare have been modified in this case, under the joint influence of the discovery of measure by Borei, and of the use of abstract sets. Their new form has been fully stated by Kolmogoroff and interpreted by Frechet who proposes to call this latest theory the 'modernized axiomatic definition' of probability. Its interpretation requires that it should be preceded by an inductive synthesis, and followed by numerical verifications.

Bibliography. The various theories outlined in this article do not exhaust the possible definitions and problems concerning probability, but they give an idea of the trend of the discussions. The following works are selected from a considerable literature of the subject.

-- T.C.
Problem: (Gr. problema, anything thrown forward) 1. Any situation, practical or theoretical, for which there is no adequate automatic or habitual response, and which therefore calls up the reflective processes. 2. Any question proposed for solution. -- A.C.B.
Problematic knowledge: Knowledge of what might occur or is capable of occurring as opposed to knowledge of what is actual or of what must occur; opposed to assertoric knowledge and apodictic knowledge. -- A.C.B.

In Kant, the domain of things beyond possible experience is completely problematic because of the a priori limitations of human knowledge (cf. J. Loewenberg, Calif. Studies in Philosophy). See Modality.

Process: (Lat. processus, pp. of procedo, to go before) A series of purposive actions, generally tending toward the production of something. A systematic forward movement, resulting in growth or decay. As employed by Whitehead (1861-), the course of actuality in its cosmological aspects. Syn. with action, becoming, existence. -- J.K.F.
Process Theory of Mind: The conception of mind in terms of process in contrast to substance. A mind, according to the process theory is a relatively permanent pattern preserved through a continuously changing process. Leibniz doctrine of the self-developing monad signalizes the transition from the substance to the process theory of mind and such philosophers as Bradley, Bosanquet, Bergson, James, Whitehead, Alexander and Dewey are recent exponents of the process theory. See C. W. Morris, Six Theories of Mind, Ch. II. -- L.W.
Proclus: (411-485) A prominent Neo-Platonist and theological commentator, who taught that man becomes united with God through the practice of love, truth and faith. Main works: Commentaries on Timeus, on Republic, on Parmenides; Instit. Theol.; In Platonis Theol., Comment on First Book of Euclid. -- R.B.W.
Projection: (Lat. projectio, from projicere, to throw forward) The mental act of attributing to sensations or sense qualia, an external and independent existence. The projection theory of Condillac and other sensationalists (see Sensationalism) asserts that sensations are first experienced as subjective states and are subsequently externalized by a special act of mind. Helmholtz restricted projection to spatial projection (the localization of sensations in space at a certain distance from the body) but the more general usage is preferable. -- L.W.
Project method: An education method which makes use of practical activities, organizing the scholastic work of the child about complex enterprises, such as making a garden, planning a circus. -- J.E.B.
Prolegomena: (Cr. pro. before; lego, say) Introductory material. (Singuhr form prolegomenon.) Cf. Prolegomena to Every Future Scientific Metaphysic, by Kant (q.v.). -- T.F.
Prolepsis: (Gr. prolepsis) Notion, preconception. The term is used by the Stoics and Epicureans to denote any primary general notion that arises spontaneously and unconsciously in the mind is distinguished from concepts that result from conscious reflection. These prolepses are regarded by the Stoics as common to all men as rational beings, and are sometimes called innate (symphytoi), though in general they were looked upon as the natural outgrowth of sense-perception. -- G.R.M.
Proof by cases: Represented in its simplest form by the valid inference of the propositional calculus, from A ⊃ C and B ⊃ C and A ∨ B to C. More complex forms involve multiple disjunctions, e.g., the inference from A ⊃ D and B ⊃ D and C⊃ D and [A ∨ B] ∨ C to D. The simplest form of proof by cases is thus the same as the simple constructive dilemma (see Logic, formal, § 2), the former term deriving from mathematical usage and the latter from traditional logic. For the more complex forms of proof by cases, and like generalizations of the other kinds of dilemma to the case of more than two major premisses, logicians have devised the names trilemma, tetralemma, polylemma -- but these are not much found in actual use. -- A.C.
Proof theory: The formalization of mathematical proof by means of a logistic system (q. v.) makes possible an objective theory of proofs and provability, in which proofs are treated as concrete manipulations of formulas (and no use is made of meanings of formulas). This is Hilbert's proof theory, or metamathematics. p A central problem of proof theory, according to Hilbert, is the proof of consistency of logistic systems adequate to mathematics or substantial parts of mathematics. -- A logistic system is said to be consistent, relatively to a particular notation in the system called negation, if there is no formula A such that both A and the negation of A are provable (i.e., are theorems). The systems with which Hilbert deals, and the notations in them which he wishes to call negation, are such that, if a formula A and its negation were once proved, every propositional formula could be proved; hence he is able to formulate the consistency by snying that a particular formula (e.g., ∼[0 = 0]) is not provable.

A consistency proof evidently loses much of its significance unless the methods employed in the proof are in some sense less than, or less dubitable than, the methods of proof which the logistic system is intended to formalize. Hilbert required that the methods employed in a consistency proof should be finitary -- a condition more stringent than that of intuitionistic acceptability. See Intuitionism (mathematical).

Gödel's theorems (see Logic, formal, § 6) are a difficulty for the Hilbert program because they show that the methods employed in a consistency proof must also be in some sense more than those which the logistic system formalizes. Godel himself remarks that the difficulty may not be insuperable.

Other problems of proof theory are the decision problem, and the problem of proving completeness (in one of various senses) for a logistic system. Cf. Logic, formal, §§ 1, 3. -- A.C.

Hilbert and Bernays,
Grundlagen der Mathematik, vol. 1, Berlin, 1934, and vol. 2, Berlin. 1939.
P. Bernays,
Sur le platonisme dans les mathematiques, and
Quelques points essentiels de la metamathematique, l'Enseignement Mathematique, vol. 34 (1935), pp. 52-95.
W. Ackermann,
Zur Widerspruchsfreiheitt der Zahlentheorie, Mathematische Annalen, vol. 117 (1940), pp 162-194.

Propensity: (Lat. propensio, from propendere, to hang forth) A term used to designate a mental appetite or desire. See Appetition. Hume applied the term to the tendency of the mind to pass from one to the other of two associated ideas. -- L.W.
Proper sensible: (in Scholasticism) That which through itself, or through its proper species is perceived by only one external sense without error, as light is perceived by the eys, sound by the ear. Common sensible is that which is perceived by several external senses through modified species of the proper sensibles, e.g. quantity, distance. Accidental sensible (sensibile per accidens) is that which falls under the external senses neither through its proper species nor through the modified species of another, but only through another with which it is joined, e.g. material substance. -- H.G.
Property: (Gr. idion; Lat. proprium) In Aristotle's logic (1) an attribute common to all members of a species and peculiar to them; (2) an attribute of the above sort not belonging to the essence of the species, but necessarily following from it. -- G.R.M.
Propitiation: The attempt by act or intent of gaining the favor of a god, removing one's guilt and the divine displeasure. Such acts have taken on innumerable forms: sacrifice of precious possessions, even of human life, of animals, by pilgrimages, tithing, self-imposed asceticism of one kind or another, fastings, rituals, tortures, contrition, etc. The substitution of some one else as an act of voluntary propitiation has found classic expression in Christian tradition in the estimation of Jesus' life and death as the supreme Ransom, Substitute and Mediator. -- V.F.
Proposition: This word has been used to mean
  1. a declarative sentence (in some particular language);
  2. the content of meaning of a declarative sentence, i e., a postulated abstract object common not only to different occurrences of the same declarative sentence but also to different sentences (whether of the same language or not) which are synonymous or, as we say, mean the same thing;
  3. a declarative sentence associated with its content of meaning.
Often the word proposition is used ambiguously between two of these meanings, or among all three.

The Port-Royal Logic defines a proposition to be the same as a judgment but elsewhere speaks of propositions as denoting judgments. Traditional logicians generally have defined a proposition as a judgment expressed in words, or as a sentence expressing a judgment, but some say or seem to hold in actual usage that synonymous or intertranslatable sentences represent the same proposition. Recent writers in many cases adopt or tend towards (b).

In articles in this dictionary by the present writer the word proposition is to be understood in sense (b) above. This still leaves an element of ambiguity, since common usage does not always determine of two sentences whether they are strictly synonymous or merely logically equivalent. For a particular language or logistic system, this ambiguity may be resolved in various ways. -- A.C.

Propositional calculus: See Logic, formal, § 1.
Propositional calculus, many-valued: The truth-table method for the classical (two-valued) propositional calculus is explained in the article logic, formal, § 1. It depends on assigning truth-tables to the fundamental connectives, with the result that every formula -- of the pure propositional calculus, to which we here restrict ourselves for the sake of simplicity -- has one of the two truth-values for each possible assignment of truth-values to the variables appearing. A formula is called a tautology if it has the truth-value truth for every possible assignment of truth-values to the variables; and the calculus is so constructed that a formula is a theorem if and only if it is a tautology.

This may be generalized by arbitrarily taking n different truth-values, t1, t2, . . . , tm, f1, f2, . . . , fn-m, of which the first m are called designated values -- and then setting up truth tables (in terms of these n truth-values) for a set of connectives, which usually includes connectives notationally the game as the fundamental connectives of the classical calculus, and may also include others. A formula constructed out of these connectives and variables is then called a tautology if it has a designated value for each possible assignment of truth-values to the variables, and the theorems of the n-valued propositional calculus are to coincide with the tautologies.

In 1920, Lukasiewicz introduced a three-valued propositional calculus, with one designated value (interpreted as true) and two non-designated values (interpreted as problematical and false respectively). Later lie generalized this to n-valued propositional calculi with one designated value (first published in 1929). Post introduced n-valued propositional calculi with an arbitrary number of designated values in 1921. Also due to Post (1921) is the notion of symbolic completeness -- an n-valued propositional calculus is symbolically complete if every possible truth-function is expressible by means of the fundamental connectives.

The case of infinitely many truth-values was first considered by Lukasiewicz. -- A.C.

Propositional function is a function (q.v.) for which the range of the dependent variable is composed of propositions (q.v.) A monadic propositional function is thus in substance a property (of things belonging to the range of the independent variable), and a dyadic propositional function a relation. If F denotes a propositional function and X1, X2, . . . , Xn denote arguments, the notation F(X1, X2, . . . , Xn) -- or [F](X1, X2, . . . , Xn) -- is used for the resulting proposition, which is said to be the value of the propositional function for the given arguments, and to be obtained from the propositional function by applying it to, or predicating it of the given arguments.

Often, however, the assumption is made that two propositional functions are identical if corresponding values are materially equivalent, and in this case we speak of propositional functions in extension (the definition in the preceding paragraph applying rather to propositional functions in intension). The values of a propositional function in extension are truth-values (q.v.) rather than propositions. A monadic propositional function in extension is not essentially different from a class (q. v.)

Whitehead and Russell use the term propositional function in approximately the sense above described, but qualify it by holding, as a corollary of Russell's doctrine of descriptions (q.v.), that propositional functions are the fundamental kind from which other kinds of functions are derived -- in fact that non-propositional ("descriptive") functions do not exist except as incomplete symbols. For details of their view, which underwent some changes between publication of the first and the second edition of Principia Mathematica, the reader is referred to that work.

Historically, the notion of a function was of gradual growth in mathematics. The word function is used in approximately its modern sense by John Bernoulli (1698, 1718). The divorce of the notion of a function from that of a particular kind of mathematical expression (analytic or quasi-algebraic) is due to Dirichlet (1837). The general logical notion of a function, and in particular the notion of a propositional function, were introduced by Frege (1879). -- Alonzo Church

Proprioceptor: See Receptor.
Prosyllogism: See Episyllogism.
Protagoras of Abdera: (about 480-410 B.C.) A leading Sophist, renowned for his philosophical wisdom; author of many treatises on grammar, logic, ethics and politics; visited Athens on numerous occasions and was finally forced to flee after having been convicted of impiety. His famous formula that man is the measure of all things is indicative of his relativism which ultimately rests upon his theory of perception according to which we know only what we perceive but not the thing perceived. -- M.F.
Protasis: (Gr. protasis, placed first) In Aristotle's logic a proposition, more particularly a proposition used as a premiss in a syllogism. -- G.R.M.
Protensity: (Lat. protensum from protendere, to stretch forth) Duration-spread considered as a primary characteristic of all conscious experience. This usage was introduced by Kant (Critique of Pure Reason, A 805- B 833) where the protensive is distinguished from the extensive and the intensive and this usage has been adopted by recent psychologists. -- L.W.
Protocol Sentences: See Basic Sentences.
Proximum genus: (Lat. nearest kind) In Aristotelian theory of definition (q.v.), must be used with differentia. -- R.B.W.
Pseudo-Statement: See Meaning, Kinds of, 5.
Psyche: (Gr. soul, World-Soul, spirit) In Plotinism, it is the name of the second emanation from the One. See Soul. -- V.J.B.
Psychic or psychical: (Gr. psychikos, from psyche, the soul) (a) In the general sense, psychic is applied to any mental phenomenon. See Psychosis, Mental, (b) In the special sense, psychic is restricted to unusual mental phenomena such as mediumship, telepathy, prescience, etc. which are the subjects of "Psychic Research." See Telepathy, Prescience, Parapsychology. -- L.W.
Psychic Fusion: The supposed merging of a number of separate psychic states to form a new state. The possibility of psychic fusion is highly questionable and alleged instances of it may be interpreted as the associative revival of images based on the memory of physical mixture. -- L.W.
Psychic Summation: See Psychic Fusion.
Psycho-analysis: The psychological method and therapeutic technique developed by Freud (see Freud, Sigmund). This method consists in the use of such procedures as free association, automatic writing and especially dream-analysis to recover forgotten memories, suppressed desires and other subconscious items which exert a disturbing influence on the conscious life of an individual. The cure of the psychic disturbances is effected by bringing the suppressed items into the full of consciousness of the individual. Psycho-analytic theory has posited a subconscious mind as a repository for the suppressed elements. Freud exaggerated the sexual origin of the suppressed desires but other psycho-analysts, notably Jung and Adler, corrected this exaggeration. The psycho-analytical school has developed its terminology in which the following are characteristic.

  1. Free association is the method of encouraging the patient to recall in random fashion experiences, particularly of childhood.
  2. A "complex" is a more or less permanent emotional system or mechjnism responsible for the mental disturbances of the patient.
  3. Libido designates the underlying sexual drive or impulse, the suppression of which is responsible for the psychic disturbance.
  4. Suppression or repression is the rejection from consciousness of desires and urges which it finds intolerable.
  5. Sublimation is the transference of a suppressed desire to a new object.

These terms are only a few samples of the elaborate and at times highly mythological terminology of psycho-analysis. -- L.W.

Psychoid: Term applied by the German neo-vitalist, H. Driesch to the psychic factor which guides the growth of organisms. -- L.W.
Psychological Atomism: Theory of the structure of mind: any mental state is analyzable into simple, discrete components and that which the total mental state was produced by fusion and composition of the atomic states. See Associationism, Mind-Stuff Theory. -- L.W.
Psychological Egoism: See Egoism, Psychological. -- C.A.B.
Psychologism: (Ger. Psychologismus) The tendency of such philosophers as Hume, J. S. Mill and William James to approach philosophical problems, whether ethical, logical, aesthetic or metaphysical, from the stand-point of psychology. Psychologismus is used by Husserl and other German writers as a term of reproach which suggests the exaggeration of the psychological to the neglect of the logical and epistemological considerations. -- L.W.
Psychologists' Fallacy: The confusion of the standpoint of the psychologist with that of the subject upon whose introspective report the psychologist relies. See Wm. James, The Principles of Psychology, Vol. I, p. 196. -- L.W.
Psychology: (Gr. psyche, mind or soul + logos, law) The science of the mind, its functions, structure and behavioral effects. In Aristotle, the science of mind, (De Anima), emphasizes mental functionsl; the Scholastics employed a faculty psychology. In Hume and the Mills, study of the data of conscious experience, termed association psychology. In Freud, the study of the unconscious (depth psychology). In behaviorism, the physiological study of physical and chemical responses. In Gestalt psychology, the study of organized psychic activity, .revealing the mind's tendency toward the completion of patterns. Since Kant, psychology has been able to establish itself as an empirical, natural science without a priori metaphysical or theological commitments. The German romanticists (q.v.) and Hegel, who had developed a metaphysical psychology, had turned to cultural history to illustrate their theories of how the mind, conceived as an absolute, must manifest itself. Empirically they have suggested a possible field of exploration for the psychologist, namely, the study of mind in its cultural effects, viz. works of art, science, religion, social organization, etc. which are customarily studied by anthropologists in the case of "primitive" peoples. But it would be as difficult to separate anthropology from social psychology as to sharply distinguish so-called "primitive" peoples from "civilized" ones.

The various branches of psychology depend on the class of problems studied (a) physiological psychology is the most experimentally exact in so far as specific physiological processes and effects (vision, hearing, reaction-time, learning curves, fatigue, effects of drugs, etc.) are measurable and controllable. Wundt established the first laboratories of experimental psychology in Germany, Pavlov in Russia, James and Cattell in the U.S.; (b) pathological or abnormal psychology deals with cases of extreme deviations of behavior from what is regarded as "normal" (a statistical term often treated as a value); (c) social psychology deals with the behavior of groups as reflected in the behavior of individuals. Cf. Le Bon's law that the mentality of a crowd or mob tends to descend to the level of a least common denominator, the lowest intelligence present.


H. Siebeck,
Gesch. der Psychol. (goes from Aristotle to Aquinas);
E. G. Boring,
History of Experimental Psychology;
Wm. James,
Principles of Psychology, 1890;
W. McDougall,
Intro. to Social Psychology;
J. B. Watson,
Psychology as Science of Behavior;
R. Woodworth,
Gestalt Psychology;
Mentality of Apes;
The Conditioned Reflex;
E. L. Thorndike,
Human Nature and the Social Order.
See Freud, Gestalt, Introspection, Mind, Subconscious.
Psychology of Religion: A scientific, descriptive study of mental life and behavior with special reference to religious activities. The aim of this study is not to criticize or evaluate religion (see Philosophy of Religion) but to describe its forms as they reflect the mental processes of men. As an extended chapter in the field of general psychology, psychology of religion reflects the various types of psychology now current. As a scientific study this subject began its fruitful career at the beginning of this century, making illuminating disclosures on the nature of conversion, varieties of religious experience, the origin and character of beliefs in God and immortality, the techniques of mystics, types of worship, etc. Due to the confused state of psychology-in-general and especially to the recent vogue of behaviorism this subject has fallen somewhat into an eclipse -- at least for the present. Cf. Wm. James: Varieties of Religious Experience, 1902. -- V.F.
Psycho-Physical Parallelism: See Parallelism, Psycho-Physical.
Psycho-Physical Problem: (Gr. psyche, soul -- physikos, physical) See Mind-Body Problem.
Psychosis: (Gr. psychosis, a giving of life or soul) (a) In the general sense, psychosis designates any mental or psychical process, just as a neurosis, in the wide sense is any neural process. (b) In the restricted sense, psychosis designates a pathological condition of mind, just as "neurosis" is an abnormal condition of the nervous system. -- L.W.
P'u: "Unwrought simplicity", the Taoist symbol of man's natural state, when his inborn powers have not been tampered with by knowledge or circumscribed by morality. -- H.H.
Publicity, Epistemic: (a) In the strict sense, publicity pertains to such data of knowledge as are directly and identically accessible to more than one knowing subject. Thus epistemological monism may assert the publicity of sense data, of universals, of moral and aesthetic values and even of God. See Epistemological Monism. (b) In a less exact sense, publicity is ascribed to any object of knowledge which may be known either directly or indirectly by more than one mind, such as physical objects, public space, etc in contrast to feelings, emotions, etc. which can be directly known only by a single subject. -- L.W.
Pudgala: (Skr. beautiful, lovely) The sou], or personal entity, admitted by some thinkers even though belonging to the schools of Buddhism (s.v.), they hold that at least a temporary individuality must be assumed as vehicle for karma (q.v.) -- K.F.L.
Pu jen: Early kings, being of "unbearing", commiserating mind, unable to bear and see others suffer, exemplified a virtuous government. (Mencius.) -- H.H.
Purana: (Skr. ancient) One of 18 or more treatises, mainly cosmological, mythological, or legendary in character and composed in p.Ch.n. times. Interspersed are ethical, philosophical and scientific observations. -- K.F.L.
Pure: (Ger. rein) In Kant: Strictly, that which is unmixed with anything sensuous or empirical. Loosely, whatever pertains to the form instead of the matter of our cognition. See Kantianism. -- O.F.K.
Pure Ego: See Ego, Pure.
Pure Experience: (Lat. purus, clean) (a) The qualitative ingredients of experience, e.g. sense data, feelings, images, etc., which remain after the ideal elimination of conceptual, interpretational and constructional factors. (b) The world of ordinary immediate experience which constitutes the point of departure for science and philosophy. See Avenarius, Kritik der reinen Erfahrumg. -- L.W.
Pure Theory of Law: An attempt to introduce the "critical" method of Kant to the understanding of positive law. Kelsen, who coined the expression, intended to create "a geometry of the totality of legal phenomena." All legal phenomena are to be reduced to norms which have the form: "If A is, then B ought to be", all norms are to be derived from one basic norm [Grundnorm]. It is the task of a theory of law to establish the unity of all legal phenomena. -- W.E.
Purism: Taste tending towards archaistic and simplified form, prevailing chiefly at the beginning of the 19th century. -- L.V.
Puritanism: A term referring, in general, to a purification of existing religious forms and practices. More specifically, Puritanism refers to that group of earnest English Protestants who broke with the Roman system more completely in objection to traditional ceremonies formalities and organizations. This moral earnestness at reformation led to the emphasis upon such commendable virtues as self-reliance, thrift, industry and initiative but it led also to unnatural self-denials and overly austere discipline. In this last respect Puritanism has come to mean an ascetic mode of living, an over-sensitive conscience and an undue repression of normal human enjoyments. Milton was Puritanism at its best. New England Puritanism in its most extreme expressions of Spartan discipline and its censorious interference with the behavior of others was Puritanism at its worst. -- V.F.
Purna: (Skr.) The plenum, a synonym for the Absolute, brahman, used by Ajatasatru in Kausitaki Upanishad 4.8. See also Brhadaranyaka Up. 5.1. -- K.F.L.
Purnatva: (Skr.) Fullness, as descriptive of reality. -- K.F.L.
Purpose: (Lat. propositus from pro, before + ponere, to place) An ideally or imaginatively envisaged plan or end of action. -- L.W.
Purposiveness: (in Kant's philosophy: die Zweckmässigkeit) Adaptation whether in the body of an animal or plant to its own needs or in a beautiful object to the human intelligence. We must not say dogmatically, Kant contends, that there is a purpose behind the phenomena, but we can say that they occur as if there were, though we cannot bring the purpose under definite concepts. -- A.C.E.
Purusa: (Skr.) "Man", a symbol for the world in the Veda (q.v.). One of the two cardinal principles of the Sankhya (q.v.) and Yoga (q.v.), representing pure spirituality, consciousness, and self. Various theories prevail in Indian philosophy, some semi-physical, others psycho-physical, or logical, taking the term to denote a real self or an entity produced by maya (q.v.). -- K.F.L.
Purusartha: (Skr.) Object (artha) of man's (purusa) pursuits, enumerated as four: kama (desire), artha (wealth), dharma (duty), moksa (liberation). Also, a statement of aims with which Indian philosophers traditionally preface their works. -- K.F.L.
Purvapaksa: (Skr.) "The prior view", the first step in a logical argument, stating the view to which exception is taken. -- K.F.L.
Pu tung hsin: The state of unperturbed mind, as a result of "maintaining firm one's will and doing no violence to the vital force" which pervades the body (Mencius.) -- H.H.
Pyrrho of Elis: (c. 365-275 B.C.) A systematic skeptic who believed that it is impossible to know the true nature of things and that the wise man suspends his judgment on all matters and seeks to attain imperturbable happiness (ataraxy) by abstaining from all passion and curiosity. See Timon of Phlius, pupil of Pyrrho. -- R.B.W.
Pythagoreanism: The doctrines (philosophical, mathematical, moral, and religious) of Pythagoras (c. 572-497) and of his school which flourished until about the end of the 4th century B.C. The Pythagorean philosophy was a dualism which sharply distinguished thought and the senses, the soul and the body, the mathematical forms of things and their perceptible appearances. The Pythagoreans supposed that the substances of all things were numbers and that all phenomena were sensuous expressions of mathematical ratios. For them the whole universe was harmony. They made important contributions to mathematics, astronomv, and physics (acoustics) and were the first to formulate the elementary principles and methods of arithmetic and geometry as taught in the first books of Euclid. But the Pythagorean sect was not only a philosophical and mathematical school (cf. K. von Fritz, Pythagorean Politics in Southern Italy, 1941), but also a religious brotherhood and a fellowship for moral reformation. They believed in the immortality and transmigration (see Metempsychosis) of the soul which they defined as the harmony of the body. To restore harmony which was confused by the senses was the goal of their Ethics and Politics. The religious ideas were closely related to those of the Greek mysteries which sought by various rites and abstinences to purify and redeem the soul. The attempt to combine this mysticism with their mathematical philosophy, led the Pythagoreans to the development of an intricate and somewhat fantastic symbolism which collected correspondences between numbers and things and for example identified the antithesis of odd and even with that of form and matter, the number 1 with reason, 2 with the soul, etc. Through their ideas the Pythagoreans had considerable effect on the development of Plato's thought and on the theories of the later Neo-platonists.


John Burnet,
Early Greek Philosophy, 3rd ed. (1920).
E. Zeller-R. Mondolfo,
La Filosofia dei Greci, vol. I (1932-1938).
E. Frank,
Plato und die sogenannten Pythagoreer (1923).
T. L Heath,
A History of Greek Mathematics, vol. I (1921).
-- E.F.