Dagobert D. Runes, Dictionary of Philosophy, 1942.
A| B| C| D| E| F| G| H| I| J| K| L| M| N| O| P| Q| R| S| T| U| V| W| X| Y| Z


I: (C.)
  1. The One, which is engendered by Tao and which in turn engenders the Two (yin and yang). (Lao Tzu.) "The Formless is the One. The One has no compare in the universe . . . It is the Great Infinite and forms the Unity. It is the life of myriad generations, everlasting without beginning, and most mysterious. It enfolds the universe and opens the portal of Tao. . . . When the One is established and the myriad things are engendered, there is Tao." (Huai-nan Tzu, d. 112 B.C.)
  2. Unity of mind, "not allowing one impression to harm another." (Hsun Tzu c 335-c 288 B.C.)
  3. The number for Heaven, as two is the number for Earth. See Ta i and T'a i.
-- W.T.C.
I: The method of difference in Neo-Mohist logic, which includes duality, absence of generic relationship, separateness, and dissimilarity. "Duality means that two things necessarily differ. Absence of generic relationship means to have no connection. Separateness means that things do not occupy the same space. Dissimilarity means having nothing in common." See Mo che. -- W.T.C.
I: Transference, a method of appellation or designation. "To name a puppy a dog is transference." See Chu and Chia. (Neo-Mohism.) -- W.T.C.
I: Change (often spelled yi), a fundamental principle of the universe, arising out of the interaction of the two cosmic forces of yin and yang, or passive and active principles, and manifested in natural phenomena, human affairs, and ideas. According to Confucian and Nco-Confucian cosmology, "In the system of Change, there is the Great Ultimate (T'ai Chi) which engenders the Two Modes (i). The Two Modes engender the Four Secondary Modes (hsiang), which in turn give rise to the Eight Trigirams (pa kua). These Eight Trigrams (or Elements) determine all good and evil and the great complexity of life." Thus it involves in the first place, the meaning of i, or simplicity from which complexity is evolved, in the second place, the meaning of hsiang, that is, phenomenon, image, form, and in the third place, the idea of "production and reproduction." -- W.T.C.
I: (a) Subjective opinion; preconceived notion. (Corfucius, Neo-Confucianism.)

(b) The will, purpose, motive; idea; which is "operation of" and "emanation from" the mind with an objective in view (Chu Hsi, 1130-1200). It is called will "when the intuitive faculty, with its pure intelligence and clear understanding, is moved and becomes active." (Wang Yang-ming, 1473-1529.) See Ch'eng i. -- W.T.C.

I: Righteousness, justice; one of the four Confucian Fundamentals of the Moral Life (ssu tuan) and the Five Constant Virtues (wu ch'ang). It is the virtue "by which things are made proper," "by which the world is regulated." It means the proper application of filial piety. It means, as in Han Yu (767-824), "the proper application of the principle of true manhood (jen)." It also means the removal of evil in the world. Mencius (371-289 B.C.) said that "righteousness is man's path, whereas true manhood is man's mind." Tung Chung-shu (177-104 B.C.) regarded it as the cardinal virtue by which one's self is rectified, whereas benevolence (jen) is the virtue by which others are pacified. To the Nco-Confucians, "seriousness (ching) is to straighten one's internal life and righteousness is to square one's external life." It is to regulate things and affairs by Reason (li). -- W.T.C.
Ich: (Ger. I, myself, me, the ego (q.v.)) In the German idealistic movement from Kant through Schopenhauer, the Ich, the final, ultimate conscious subject, plays a central and dynamic role. Kant discredited the traditional Cartesian conception of a simple, undecomposable, substantial I, intuitively known. On his view, the Ich is not a substance, but the functional, dynamic unity of consciousness -- a necessary condition of all experience and the ultimate subject for which all else is object. This "transcendental unity of apperception," bare consciousness as such, is by its very nature empty, it is neither a thing nor a concept. For the pute transcendental I, my empirical self is but one experience among others in the realm of phenomena, and one of which Kant does not seek an adequate definition. The stress on the pure I as opposed to the empirical self is carried over into his practical philosophy, where the moral agent becomes, not the concrete personality, but a pure rational will, i.e., a will seeking to act in accordance with an absolute universal law of duty, the categorical imperative (q.v.).

Fichte conceives the ultimate Ich as an absolute, unconditioned, simple ego which "posits" itself and its not-self in a series of intellectual acts. He emphasizes the dynamic, creative powers of the ego, its capacity for self-determination, the act in which the absolute subject creates the I. Self and not-self are products of the original activity of the conscious subject. Schelling conceives the I as a creation of the Absolute Idea. Hegel, however, treats the Ich as thought conceived as subject, as thinking, abstracted from all things perceived, willed or felt -- in short abstracted from all experience. As such it is universal abstract freedom, an ideal unity.

From this point the notion of Ich in the German idealistic tradition passes into

  1. voluntaristic channels, with emphasis on the dynamic will, as in Schopenhiuer, Eduard von Hartmann and Nietzsche;
  2. the pragmatic-psychologic interpretation, typified by Lotze and other post-idealists; and
  3. such reconstructions of the transcendental I as are to be found in the school of Husserl and related groups.
-- O.F.K.
Icon: (Gr. eikon, image) Any sign which is like the thing it represents. -- A.C.B.
Iconoclasm: Religious struggle against images (8th and 9th centuries) and towards symbolic art. -- L.V.
Iconology: Studies in history of art concerned with the interpretation of the matter or subject treated by artists without consideration of their personalities. -- L.V.
Idanta: (Skr. "this-ness") Thingness, the state of being a this, an object of knowledge. -- K.F.L.
Idea: (Gr. idea) This term has enjoyed historically a considerable diversity of usage.
  1. In pre-Platonic Greek: form, semblance, nature, fashion or mode, class or species.
  2. Plato (and Socrates): The Idea is a timeless essence or universal, a dynamic and creative archetype of existents. The Ideas comprise a hierarchy and an organic unity in the Good, and are ideals as patterns of existence and as objects of human desire.
  3. The Stoics: Ideas are class concepts in the human mind.
  4. Neo-Platonism: Ideas are archetypes of things considered as in cosmic Mind (Nous or Logos).
  5. Early Christianity and Scholasticism: Ideas are archetypes eternally subsistent in the mind of God.
  6. 17th Century: Following earlier usage, Descartes generally identified ideas with subjective, logical concepts of the human mind. Ideas were similarly treated as subjective or mental by Locke, who identified them with all objects of consciousness. Simple ideas, from which, by combination, all complex ideas are derived, have their source either in sense perception or "reflection" (intuition of our own being and mental processes).
  7. Berkeley: Ideas are sense objects or perceptions, considered either as modes of the human soul or as a type of mind-dependent being. Concepts derived from objects of intuitive introspection, such as activity, passivity, soul, are "notions."
  8. Hume: An Idea is a "faint image" or memory copy of sense "impressions."
  9. Kant: Ideas are concepts or representations incapable of adequate subsumption under the categories, which escape the limits of cognition. The ideas of theoretical or Pure Reason are ideals, demands of the human intellect for the absolute, i.e., the unconditioned or the totality of conditions of representation. They include the soul, Nature and God. The ideas of moral or Practical Reason include God, Freedom, and Immortality. The ideas of Reason cannot be sensuously represented (possess no "schema"). Aesthetic ideas are representations of the faculty of imagination to which no concept can be adequate.
-- W.L.
  1. Pertaining to ideas (q.v.)
  2. Mental.
  3. Possessing the character of completely satisfying a desire or volition. A state of perfection with respect to a standard or goal of will or desire.
  4. A norm, perfect type, or goal, an object of desire or will, whether or not conceived as attainable.
-- W.L.
Idealism: Any system or doctrine whose fundamental interpretative principle is ideal. Broadly, any theoretical or practical view emphasizing mind (soul, spirit, life) or what is characteristically of pre-eminent value or significance to it. Negatively, the alternative to Materialism. (Popular confusion arises from the fact that Idealism is related to either or both uses of the adjective "ideal," i.e., (a) pertaining to ideas, and (b) pertaining to ideals. While a certain inner bond of sympathy can be established between these two standpoints, for theoretical purposes they must be clearly distinguished.) Materialism emphasizes the spatial, pictorial, corporeal, sensuous, non-valuational, factual, and mechanistic. Idealism stresses the supra- or non-spatial, non-pictorial, incorporeal, suprasensuous, normative or valuational, and teleological. The term Idealism shares the unavoidable expansion of such words as Idea, Mind, Spirit, and even Person, and in consequence it now possesses usefulness only in pointing out a general direction of thought, unless qualified, e.g., Platonic Idealism, Personal Idealism, Objective Idealism, Moral Idealism, etc.

The term appeared in the later 17th century to name (a) the theory of archetypal Ideas, whether in the original Platonic teaching or as incorporated into Christian Platonic and Scholastic theism; (b) the epistemological doctrine of Descartes and Locke, according to which "ideas," i.e., direct objects of human apprehension, are subjective and privately possessed. Since this latter view put in doubt the very existence of a material world, the term began to be used in the early 18th century for acosmism (according to which the external world is only the projection of our minds), and immaterialism (doctrine of the non-existence of material being). Its use was popularized by Kant, who named his theory of knowledge Critical or Transcendental Idealism, and by his metaphysical followers, the Post-Kantian Idealists.

Metaphysics. Pure Idealism or Immaterialism identifies ontological reality (substance, substantives, concrete individuality) exclusively with the ideal, ie., Mind, Spirit, Soul, Person, Archetypal Ideas, Thought. See Spiritualism, Mentalism, Monadism, Panpsychtsm, Idealistic Phenomenalism. With respect to the metaphysical status of self-consciousness and purposeful activity, Idealism is either impersonalistic or personalistic. See Personalism.

Impersonalistic Idealism identifies ontological reality essentially with non-conscious spiritual principle, unconscious psychic agency, pure thought, impersonal or "pure" consciousness, pure Ego, subconscious Will, impersonal logical Mind, etc. Personalistic Idealism characterizes concrete reality as personal selfhood, i.e., as possessing self-consciousness. With respect to the relation of the Absolute or World-Ground (s.) to finite selves or centers of consciousness, varying degrees of unity or separateness are posited. The extreme doctrines are radical monism and radical pluralism. Monistic Idealism (pantheistic Idealism) teaches that the finite self is a part, mode, aspect, moment, appearance or projection of the One. Pluralistic Idealism defends both the inner privacy of the finite self and its relative freedom from direct or causal dependence upon the One. With respect to Cosmology, pure idealism is either subjective or objective. Subjective Idealism (acosmism) holds that Nature is merely the projection of the finite mind, and has no external, real existence. (The term "Subjective Idealism" is also used for the view that the ontologically real consists of subjects, i.e., possessors of experience.) Objective Idealism identifies an externally real Nature with the thought or activity of the World Mind, (In Germany the term "Objective Idealism" is commonly identified with the view that finite minds are parts -- modes, moments, projections. appearances, members -- of the Absolute Mind.) Epistemological Idealism derives metaphysical idealism from the identificition of objects with ideas. In its nominalistic form the claim is made that "To be is to be perceived." From the standpoint of rationalism it is argued that there can be no Object without a Subject. Subjects, relations, sensations, and feelings are mental; and since no other type of analogy remains by which to characterize a non-mental thing-in-itself, pure idealism follows as the only possible view of Being.

Realistic Idealism recognizes the reality of non-ideal types of being, but relegates them to a subordinate status with respect either to quantity of being or power. This view is either atheistic or theistic. Realistic theism admits the existence of one or more kinds of non-mental being considered as independently co-eternal with God, eternally dependent upon Deity, or as a divine creation. Platonic Idealism, as traditionally interpreted, identifies absolute being with timeless Ideas or disembodied essences. Thtse, organically united in the Good, are the archetypes and the dynamic causes of existent, material things. The Ideas are also archetypes of rational thought, and the goal of fine art and morality. Axiological Idealism, a modern development of Platonism and Kantianism, maintains that the category of Value is logically and metaphysically prior to that of Being.

The idealistic doctrine known as Conceptual Realism identifies the logical (and at times the perceptual) content of experience with universals (essences, objectives, subsistents, etc.) considered as non-mental, i.e. as essentially independent of cognitive subjects.

Epistemology. Theistic Platonism maintains that the archetypes of existent things are eternal ideas in the mind of God. Epistemological Idealism teaches that all entities other than egos or subjects of experience are exclusively noetic objects, i.e. have no existence or reality apart from the relation of being perceived or thought. Transcendental Idealism (Critical Idealism) is Kant's name for his doctrine that knowledge is a synthetic, relational product of the logical self (transcendental unity of apperception). Phenomenology is Husserl's name for the science that investigates the essences or natures of objects considered apart from their existential or metaphysical status.

Ethics. Any system of moral theory may be called Ethical Idealism, whether teleological or formal in principle, which accepts several of the following:

  1. a scale of values, moral principles, or rules of action;
  2. the axiological priority of the universal over the particular;
  3. the axiological priority of the spiritual or mental over the sensuous or material;
  4. moral freedom rather than psychological or natural necessity.
In popular terminology a moral idealist is also identified with the doctrinaire, as opposed to the opportunist or realist; with the Utopian or visionary as opposed to the practicalist, with the altruist as opposed to the crass egoist.

Aesthetics. Any system or program of fine art emphasizing the ideal (s.) is Aesthetic Idealism.

  1. The view that the goal of fine art is an embodiment or reflection of the perfections of archetypal Ideas or timeless essences (Platonism).
  2. The view of art which emphasizes feeling, sentiment, and idealization (as opposed to "literal reproduction" of fact).
  3. The view of art which emphasizes cognitive content (as opposed to abstract feeling, primitive intuition, formal line or structure, mere color or tone).
Psychology. The doctrine that ideas or judgments are causes of thought and behavior, and not mere effects or epiphenomena, is Psychological Idealism.

History. Inasmuch as pure or basic Materialism has been an infrequent doctrine among major thinkers, the history of philosophy broadly understood, is largely the history of Idealism.

India. Intimations of advanced theism, both in a deistic and immanentistic form, are to be found in the Rig Veda. The early Upanishads in general teach variously realistic deism, immanent theism, and, more characteristically, mystical, impersonal idealism, according to which the World Ground (brahman) is identified with the universal soul (atman) which is the inner or essential self within each individual person. The Bhagavad Gita, while mixing pantheism, immanent theism, and deism, inclines towards a personahstic idealism and a corresponding ethics of bhakti (selfless devotion). Jainism is atheistic dualism, with a personalistic recognition of the reality of souls. Many of the schools of Buddhism (see Buddhism) teach idealistic doctrines. Thus a monistic immaterialism and subjectivism (the Absolute is pure consciousness) was expounded by Maitreya, Asanga, and Vasubandhu. The Lankavatarasutra combined monistic, immaterialistic idealism with non-absolutistic nihilism. Subjectivistic, phenomenalistic idealism (the view that there is neither absolute Pure Consciousness nor substantial souls) was taught by the Buddhists Santaraksita and Kamalasila. Examples of modern Vedantic idealism are the Yogavasistha (subjective monistic idealism) and the monistic spiritualism of Gaudapada (duality and plurality are illusion). The most influential Vedantic system is the monistic spiritualism of Sankara. The Absolute is pure indeterminate Being, which can only be described as pure consciousness or bliss. For the different Vedantic doctrines see Vedanta and the references there. Vedantic idealism, whether in its monistic and impersonalistic form, or in that of a more personalistic theism, is the dominant type of metaphysics in modern India. Idealism is also pronounced in the reviving doctrines of Shivaism (which see).

China. The traditional basic concepts of Chinese metaphysics are ideal. Heaven (T'ien), the spiritual and moral power of cosmic and social order, that distributes to each thing and person its alloted sphere of action, is theistically and personalistically conceived in the Shu Ching (Book of History) and the Shih Ching (Book of Poetry). It was probably also interpreted thus by Confucius and Mencius, assuredly so by Motze. Later it became identified with Fate or impersonal, immaterial cosmic power. Shang Ti (Lord on High) has remained through Chinese history a theistic concept. Tao, as cosmic principle, is an impersonal, immaterial World Ground. Mahayana Buddhism introduced into China an idealistic influence. Pure metaphysical idealism was taught by the Buddhist monk Hsuan Ch'uang. Important Buddhist and Taoist influences appear in Sung Confucianism (Ju Chia). a distinctly idealistic movement. Chou Tun I taught that matter, life and mind emerge from Wu Chi (Pure Being). Shao Yung espoused an essential objective idealism: the world is the content of an Universal Consciousness. The Brothers Ch'eng Hsao and Ch'eng I, together with Chu Hsi, distinguished two primordial principles, an active, moral, aesthetic, and rational Law (Li), and a passive ether stuff (Ch'i). Their emphasis upon Li is idealistic. Lu Chiu Yuan (Lu Hsiang Shan), their opponent, is interpreted both as a subjective idealist and as a realist with a stiong idealistic emphasis. Similarly interpreted is Wang Yang Ming of the Ming Dynasty, who stressed the splritual and moral principle (Li) behind nature and man.

Persia. The theology of Zarathustra was a realistic and dualistic personalism. Nature is assumed to be a plastic order controlled by Ahura Mazda, personalized spirit of Good, against whom struggles in vain Ahriman, the personalized spirit of Evil.

Israel. In the period of the written prophets Jewish thought moved to a personalistic and realistic theism, reaching maturity in Jeremiah and Genesis I. The cosmic "I Am" is a personal and righteous World Ground who fashions and controls both Nature and human history.

Greece. Homeric thought centered in Moira (Fate), an impersonal, immaterial power that distributes to gods and men their respective stations. While the main stream of pre-Socratic thought was naturalistic, it was not materialistic. The primordial Being of things, the Physis, is both extended and spiritual (hylozoism). Soul and Mind are invariably identified with Physis. Empedocles' distinction between inertia and force (Love and Hate) was followed by Anaxagoras' introduction of Mind (Nous) as the first cause of order and the principle of spontaneity or life in things. Socrates emphasized the ideological principle and introduced the category of Value as primary both in Nature and Man. He challenged the completeness of the mechanical explanation of natural events. Plato's theory of Ideas (as traditionally interpreted by historians) is at once a metaphysics, epistemology, and axiology. Ideas, forming a hierarchy and systematically united in the Good, are timeless essences comprising the realm of true Being. They are archetypes and causes of things in the realm of Non-Being (Space). Aristotle, while moving in the direction of common-sense realism, was also idealistic. Forms or species are secondary substances, and collectively form the dynamic and rational structure of the World. Active reason (Nous Poietikos), possessed by all rational creatures, is immaterial and eternal. Mind is the final cause of all motion. God is pure Mind, self-contained, self-centered, and metaphysically remote from the spatial World. The Stoics united idealism and hylozoistic naturalism in their doctrine of dynamic rational cosmic law (Logos), World Soul, Pneuma, and Providence (Pronoia).

Alexandrian-Roman Period. Fed by Eastern ideas, later Alexandrian-Roman thought was essentially idealistic. In neo-Pythagorean, Neo-Platonic and Alexandrian Christianity, matter was identified with non-being, and placed at the metaphysical antipodes with respect to God or the Absolute. Early Christianity identified itself with the personalistic theism of Israel, Pauline spiritualism, and the neo-Platonism of Alexandria.

Medieval Period. Medieval Christian thought, axiomatically idealistic, united the personalism of Israel and the speculative idealism of neo-Platonism and Aristotle. Similarly, Islamic thought, centering at Bagdad and Cordova, attached Mohammedan religious idealism to neo-Platonism and Aristotelianism.

Modern Period. In the 17th century the move towards scientific materialism was tempered by a general reliance on Christian or liberal theism (Galileo, Bacon, Descartes, Hobbes, Gassendi, Toland, Hartley, Priestley, Boyle, Newton). The principle of gravitation was regarded by Newton, Boyle, and others, as an indication of the incompleteness of the mechanistic and materialistic account of the World, and as a direct proof of the existence of God. For Newton Space was the "divine sensorium". The road to pure modern idealism was laid by the epistemological idealism (epistemological subjectivism) of Campanella and Descartes. The theoretical basis of Descartes' system was God, upon whose moral perfection reliance must be placed ("God will not deceive us") to insure the reality of the physical world. Spinoza's impersonalistic pantheism is idealistic to the extent that space or extension (with modes of Body and Motion) is merely one of the infinity of attributes of Being. Leibniz founded pure modern idealism by his doctrine of the immateriality and self-active character of metaphysical individual substances (monads, souls), whose source and ground is God. Locke, a theist, gave chief impetus to the modern theory of the purely subjective character of ideas. The founder of pure objective idealism in Europe was Berkeley, who shares with Leibniz the creation of European immaterialism. According to him perception is due to the direct action of God on finite persons or souls. Nature consists of (a) the totality of percepts and their order, (b) the activity and thought of God. Hume later an implicit Naturalist, earlier subscribed ambiguously to pure idealistic phenomenalism or scepticism. Kant's epistemological, logical idealism (Transcendental or Critical Idealism) inspired the systems of pure speculative idealism of the 19th century. Knowledge, he held, is essentially logical and relational, a product of the synthetic activity of the logical self-consciousness. He also taught the ideality of space and time. Theism, logically undemonstrable, remains the choice of pure speculative reason, although beyond the province of science. It is also a practical implication of the moral life. In the Critique of Judgment Kant, marshalled facts from natural beauty and the apparent teleological character of the physical and biological world, to leave a stronger hint in favor of the theistic hypothesis. His suggestion thit reality, as well as Mind, is organic in character is reflected in the idealistic pantheisms of his followers: Fichte (abstract personalism or "Subjective Idealism"), Schellmg (aesthetic idealism, theism, "Objective Idealism"), Hegel (Absolute or logical Idealism), Schopenhauer (voluntaristic idealism), Schleiermacher (spiritual pantheism), Lotze ("Teleological Idealism"). 19th century French thought was grounder in the psychological idealism of Condillac and the voluntaristic personalism of Biran. Throughout the century it was essentially "spiritualistic" or personalistic (Cousin, Renouvier, Ravaisson, Boutroux, Lachelier, Bergson). British thought after Hume was largely theistic (A. Smith, Paley, J. S. Mill, Reid, Hamilton). In the latter 19th century, inspired largely by Kant and his metaphysical followers, it leaned heavily towards semi-monistic personalism (E. Caird, Green, Webb, Pringle-Pattison) or impersonalistic monism (Bradley, Bosanquet). Recently a more pluralistic personalism has developed (F. C. S. Schiller, A. E. Taylor, McTaggart, Ward, Sorley). Recent American idealism is represented by McCosh, Howison, Bowne, Royce, Wm. James (before 1904), Baldwin. German idealists of the past century include Fechner, Krause, von Hartmann, H. Cohen, Natorp, Windelband, Rickert, Dilthey, Brentano, Eucken. In Italy idealism is represented by Croce and Gentile, in Spain, by Unamuno and Ortega e Gasset; in Russia, by Lossky, in Sweden, by Boström; in Argentina, by Aznar. (For other representatives of recent or contemporary personalism, see Personalism.) -- W.L.

Ideality: Condition of being mental. -- W.L.
Ideal of Reason: (Ger. Ideal der Vernunft) Kant: The idea of an all-comprehending reality, God, containing the determination of all finite existence. In the Cr. of Pure Reason Kant shows how and why the mind hypostatizes this Ideal, the source of "transcendental illusion" (q.v.). He concluded that while the traditional proofs of God's existence were all fallacious, the idea of God had a regulative use for reason, and was a necessary postulate for practical reason (q.v.). See Kantianism. -- O.F.K.
Ideal Utilitarianism: See Utilitarianism.
Idealization: In art, the process of generalizing and abstracting from specifically similar individuals, in order to depict the perfect type of which they are examples, the search for real character or structural form, to the neglect of external qualities and aspects. Also, any work of art in which such form or character is exhibited; i.e. any adequate expression of the perfected essence inadequately manifested by the physical particular. In classical theory, the object so discovered and described is a Form or Idea; in modern theory, it is a product of imagination. -- I.J.
Ideas of Pure Reason: (Kant. Ger. Ideen der reinen Vernunft) Ideas, expounded and criticized in the "Transcendental Dialectic" of the Cr. of Pure Reason, in which an absolute whole determines the parts in an aggregate or as series. For Kant there were three such Ideas: the soul, the world, and God. He maintained that these Ideas did not constitute "objects", but claimed for them a regulative use in pure reason, and asserted their reality as postulates of practical reason. See Kantianism. -- O.F.K.
Ideatum: Noun denoting the object of an idea or that which is represented in the mind by the idea. Also applied to really existing things outside the mind corresponding to the concepts in consciousness. -- J.J.R.
Identity: (Lat. identicus, from identidem, repeatedly) In psychology: personal identity, or the continuous existence of the personality despite physiological and psychological changes. See Identity, law of -- J.K.F.
Identity, law of: Given by traditional logicians as "A is A." Because of the various possible meanings of the copula (q.v.) and the uncertainty as to the range of the variable A, this formulation is ambiguous. The traditional law is perhaps best identified with the theorem x = x, either of the functional calculus of first order with equality, or in the theory of types (with equality defined), or in the algebra of classes, etc. It has been, or may be, also identified with either of the theorems of the propositional calculus, p ⊃ p, p ≡ p, or with the theorem of the functional calculus of first order, F(x) ⊃x F(x). Many writers understand, however, by the law of identity a semantical principle -- that a word or other symbol may (or must) have a fixed referent in its various occurrences in a given context (so, e.g., Ledger Wood in his The Analysis of Knowledge). Some, it would seem, confuse such a semantical principle with a proposition of formal logic. -- A.C.
Identity-philosophy: In general the term has been applied to any theory which failed to distinguish between spirit and matter, subject and object, regarding them as an undifferentiated unity; hence such a philosophy is a species of monism. In the history of philosophy it usually signifies the system which has been called Identitätsphilosophie by Friedrich Wilhelm Schelling who held that spirit and nature are fundamentally the same, namely, the Absolute. Neither the ego nor the non-ego are the ultimate principles of being; they are both relative concepts which are contained in something absolute. This is the supreme principle of Absolute Identity of the ideal and the real. Reasoning does not lead us to the Absolute which can only be attained by immediate intellectual intuition. In it we find the eternal concepts of things and from it we can derive everything else. We are obliged to conceive the Absolute Identity as the indifference of the ideal and the real. Of course, this is God in Whom all opposites are united. He is the unity of thought and being, the subjective and the objective, form and essence, the general and infinite, and the particular and finite. This teaching is similar to that of Spinoza. -- J.J.R.
Ideogenetic Theory: (Gr. eidos, idea + genesis, origin) Theory of Brentano (see Brentano, Franz) and other phenomenologists (see Phenomenology) which holds that judgment is an original act of consciousness directed towards presentations. The term is a translation of the German ideogenetische Urteile. -- L.W.
  1. Pertaining to the school of Condidillac and his French followers of the early 19th century.
  2. Pertaining to theories determined by cultural environment or non-rational interests.
  3. Idle, unrealistic, fanciful.
-- W.L.
Ideology: A term invented by Destutt de Tracy for the analysis of general ideas into the sensations from which he believed them to emanate. The study was advocated as a substitute for metaphysics.

The term was used in a derogatory sense by Napoleon to denominate all philosophies whose influence was republican. In recent times the English equivalent has come to mean: (1) in some economic determinists, ineffectual thoughts as opposed to causally efficacious behavior, (2) any set of general ideas or philosophical program. -- G.B.

Ideo-motor Action: (Gr. eidos, idea + motus, motion) Bodily action directly induced by the prevalence of an idea in the mind and considered by W. James as the basis of volition. (See W. James, The Principles of Psychology, Vol. II, pp. 522 ff.) -- L.W.
Idio-psychological Ethics: Ethics based on the inner facts of conscience, as contrasted with hetero-psychological ethics, or ethics based on mental categories other than the conscience. Introduced as terms into ethics by J. Martineau (1805-1899) in 1885. -- J.K.F.
Idol: (Gr. eidolon, and Lat. idolum, image or likeness) Democritus (5th c. B.C.) tried to explain sense perception by means of the emission of little particles (eidola) from the sense object. This theory and the term, idolum, are known throughout the later middle ages, but in a pejorative sense, as indicating a sort of "second-hand" knowledge. G. Bruno is usually credited with the earliest Latin use of the term to name that which leads philosophers into error, but this is an unmerited honor. The most famous usage occurs in F. Bacon's Novum Oiganum, I, 39-68, where the four chief causes of human error in philosophy and science are called the Idols of the Tribe (weakness of understanding in the whole human race), of the Cave (individual prejudices and mental defects), of the Forum (faults of language in the communication of ideas), and of the Theatre (faults arising from received systems of philosophy). A very similar teaching, without the term, idol, had been developed by Grosseteste and Roger Bacon in the 13th century. -- V.J.R.
Ignorance: (Lat. in, not + noscere, to become acquainted with) Partial or complete absence of knowledge. -- A.C.B.
Ignoratio elenchi: The fallacy of irrelevance, i.e., of proving a conclusion which is other than that required or which does not contradict the thesis which it was undertaken to refute. -- A.C.
I kuan: The "one thread" or central principle that runs through the teachings of Confucius. See Chung yung. This is interpreted as
  1. The Confucian doctrine of being true to the principles of one's nature (chung) and the benevolent exercise of them in relation to others (shu), by Confucius' pupil, Tseng Tzu.
  2. The central principle of centrality and harmony (chung yung) by which all human affairs and natural phenomena may be understood. (Earlv Confucianism.)
  3. "Man and things forming one organic unity," there being no discrimination between the self and the non-self. (Ch'eng I-ch'uan, 1033-1107.)
  4. Sincerity (ch'eng), which is the way of Heaven, indestructible, by which all things are in their proper places. Sincerity is the thread that runs through all affairs and things, and being true to the principles of one's nature and the benevolent exercise of them in relation to others is the way to try to be sincere. (Chu Hsi, 1130-1200.)
  5. The "one" is the Great Ultimate in general and the "thread" is the Great Ultimate in each thing. (Chu Hsi.)
-- W.T.C.
Illative: Having to do with inference. -- A.C.
Illicit importance, fallacy of: The mistake of assuming that because a proposition is self-evident, it is therefore important. -- H.H.
Illicit process of the major: In the categorical syllogism (Logic, formal, § 5), the conclusion cannot be a proposition E or O unless the major term appears in its premiss as distributed -- i.e., as subject of a proposition A or E, or the predicate of a proposition E or O. Violation of this rule is the fallacy of illicit process of the major. -- A.C.
Illicit process of the minor: In the categorical syllogism (logic, formal, § 5), the conclusion cannot be a proposition A or E unless the minor term appears in its premiss as distributed -- i.e., as the subject of a proposition A or E, or the predicate of a proposition E or O. Violation of this rule is the fallacy of illicit process of the minor. -- A.C.
Illumination: Source of contemplation, transfiguration of emotional life for the attainment of measure and harmony (Schleiermacher). -- L.V.
Illusion: (Lat. in + ludere, to play) An illusion of sense is an erroneous perception arising from a misinterpretation of data of sense because they are produced under unusual conditions of perception, physical, physiological or psychological. Illusion contrasts with hallucination in which the sensuous ingredients are totally absent. See Delusion; Hallucination. -- L.W.
Illusionism: The view that the spatial-temporal external world is merely a veil of maya, a phantasmagoria. Not only is everything illusion, deception, appearance, but existence itself has no real value. (Schopenhauer.) -- H.H.
Image: (Lat. imago, likeness) A sensory quality reinstated by the mind in the absence of sensory stimulation. -- L.W.

Medieval: Image and Similitude are frequently used by the medieval scholars. Neither of them needs mean copy. Sometimes the terms are nearly synonymous with sign in general. The alteration of the sense organs when affected by some external object is an image of the latter (species sensibilis); so is the memory image or phantasm. The intelligible species resulting from the operation of the active intellect on the phantasm is not less an image of the universal nature than the concept and the word expressing the latter is. Images in the strict sense of copies or pictures are only a particular case of image or similitude in general. The idea that Scholasticism believed that the mind contains literally "copies" of the objective world is mistaken interpretation due to misunderstanding of the terms. -- R.A.

Imageless Thought: Conceptual meanings not embodied in sensuous imagery. The existence of imageless thought was a subject of controversy among American and German psychologists about 1910; imageless thought was affirmed by Kulpe, and Bühler, but was rejected by Titchener. -- L.W.
Imagination: Imagination designates a mental process consisting of:
  1. The revival of sense images derived from earlier perceptions (the reproductive imagination), and
  2. the combination of these elementary images into new unities (the creative or productive imagination.) The creative imagination is of two kinds:
    1. the fancy which is relatively spontaneous and uncontrolled, and
    2. the constructive imagination, exemplified in science, invention and philosophy which is controlled by a dominant plan or purpose.
-- L.W.
Imitation: In aesthetics, the general theory that artistic creation is primarily an imitative or revelatory process, and the work of art an imitation or representation. Such theories hold that the artist discovers, and in his work imitates, real Forms, and not physical objects, art is conceived as a revelation of a spiritual realm, and so as the exhibition of the essential character of the particular object represented. The work of art reveals adequately the essence which the physical thing manifests inadequately. In modern expressionistic theory, imitation is conceived as servile reproduction of obvious external qualities, a mere copying of a particular, and so is denounced. -- I.J.
Immanence: (late Lat. Immanere, to remain in) The state of being immanent, present, or in dwelling.
  1. In Medieval Scholasticism a cause is immanent whose effects are exclusively within the agent, as opposed to transient.
  2. For Kant the immanent is experiential as opposed to non-experiential or transcendent.
  3. In modern metaphysics and theology immanence signifies presence (of essence, being, power, etc.), as opposed to absence.
According to pantheism the essence of God or the Absolute is completely immanent in the world, i.e. is identical with it. According to Deism God is essentially absent or transcendent from the world. According to immanent theism He is both immanent (in presence and activity) and transcendent (in essence) with respect to it. Mysticism in its broadest sense posits the mutual immanence of the human and the divine. -- W.L.
Immanence philosophy: In Germany an idealistic type of philosophy represented by Wilhelm Schuppe (1836-1913), which combines elements of British empiricism, Kant, and Fichte. It rejects any non-conscious thing-in-itself, and identifies the Real with consciousness considered as an inseparable union of the "I" and its objects. The categories are restricted to identity-difference and causality. To the extent that the content of finite consciousness is common to all or "trans-subjective" it is posited as the object of a World Consciousness or Bewusstsein Ueberhaupt. Consequently the World is "immanent" in each finite consciousness rather than essentially transcendent. -- W.L.
Immanent and Transient Activity: In logic, the activity of the mind which produces no effect upon the object of knowledge is called immanent, that which does have such an effect is called transient (or transitive). According to Kant, the immanent use of the understanding is valid, since it deals only with subject-matter furnished by the senses, while the transcendent effort to conceive of things as they are in themselves is illegitimate. In Christian theology, Jesus was created by an immanent act, and the world by a transient, act. -- J.K.F.
Immanent Theism: Doctrine that God is both immanent and transcendent with respect to the World. This view differs from Pantheism (q.v.) by denying that God's essence is identical with that of the World. -- W.L.
Immaterialism: Doctrine of the non-existence of material or corporeal reality. Pure Idealism. -- W.L.
Immateriality: (Scholastic) Immaterial substances are the human soul and the subsistent forms, the angels. The rational faculties of the human soul, intellect and will are called immaterial and believed to need no bodily organ for their performances, although they depend on the senses for their activities. Their immateriality is proved by their capacity of becoming cognizant of the universals and of reflection on their own performances. -- R.A.
Immediacy: (Lat. in + medius, middle) Immediacy is used in two senses:
  1. Contrasted with representation, immediacy is the direct presence to the mind of the object of knowledge. See Presentational immediacy.
  2. Contrasted with mediation, immediacy consists in the absence or minimal and submerged presence of inference, interpretation and construction in any process of knowledge.
In this sense perception and memory are relatively immediate whereas scientific and philosophical theories are mediate. -- L.W.
Immediate inference: See Logic, formal, § 4.
Immoralism: Monl indifference, in general the combating of traditional morality. (Nietzsche.) -- H.H.
Immortality: (Lat. in + mortalis, mortal) The doctrine that the soul or personality of man survives the death of the body. The two principal conceptions of immortality are:
  1. temporal immortality, the indefinite continuation of the individual mind after death and
  2. eternity, ascension of the soul to a higher plane of timelessness.

Immortality is properly speaking restricted to post-existence (survival after death) but is extended by the theory of transmigration of souls. (See Metempsychosis) to include pre-exisence (life before birth).

The arguments for immortality fall into four groups:

  1. Metaphysical arguments which attempt to deduce immortality from properties of the soul such as simplicity, independence of the body, its knowledge of eternal truth, etc.
  2. Valuational and moral arguments seek to derive the immortality of the soul from its supreme worth or as a presupposition of its moral nature.
  3. Empirical arguments which adduce as evidence of immortality, automatic writing, mediumship and other spiritualistic phenomena.
-- L.W.
Immutability: Changelessness, or the state or quality of not being susceptible to any alteration. An attribute of God denoting that His nature is essentially incapable of any internal change whatsoever. -- J.J.R.
Impersonalism: The mechanistic conception of the unconditional regularity of nature in mechanics, physics, and the sciences of the living organism. Opposite of Personalism. -- R.T.F.
Implication: See Logic, formal, §§1, 3; Strict implication.
Importation: The form of valid inference of the propositional calculus from
A ⊃ [B ⊃ C] to AB ⊃ C.
The law of importation is the theorem of the propositional calculus:
[p ⊃ [q ⊃ r]] ⊃ [pq ⊃ r].
-- A.C.
Imposition: In Scholastic logic, grammatical terms such as noun, pronoun, verb, tense, conjugation were classed as terms of second imposition, other terms as of first imposition. The latter were subdivided into terms of first and second intention (q. v.). -- A.C.
Impredicative definition: Poincare in a proposed resolution (1906) of the paradoxes of Burali-Forti and Richard (see Paradoxes, logical), introduced the principle thnt, in making a definition of a particular member of any class, no reference should be allowed to the totality of members of that class. Definitions in violation of this principle were called impredicative (non predicatives) and were held to involve a vicious circle.

The prohibition against impredicative definition was incorporated by Russell into his ramified theory of types (1908) and is now usually identified with the restriction to the ramified theorv of types without the axiom of reducibility. (Poincare, however, never made his principle exact and may have intended, vaguely, a less severe restriction than this -- as indeed some passages in later writings would indicate.) -- A. C.

H. Poincare, Les mathematiques et la logique. Revue de Metaphysique et de Morale, vol. 14 (1906), pp. 294-317. R. Carnap, The Logical Syntax of Language, New York and London, 1937.

Impression: Act or process of affecting; effect or influence of such, especially psychological, immediate or momentnry effect; stimulation of neural processes apart from its effect, immediate effect in consciousness of neural stimulation; immediate, uninterpreted ditum of consciousness, especially of aesthetic objects; sensuous image; relatively vivid perceptual datum as against a fainter idea. See Hume. -- M.T.K.
Impressionism: As a general artistic movement, the theory that art should strive only to reveal the felt quality of an object, scene, or event; i.e. the total effect that it creates in the artist. Specifically in painting, the general idea underling practice is to render the immediate visual appearance of the object, independently of its physical structure and its meaning for the mind. Emphasis is placed on capturing ephemeral surface aspects of things as disclosed by changes in light, neglecting any supposed real thing which undergoes these changes and underlies these aspects. -- I.J.
In and for itself: (Ger. an und für sich) An sich is the given primary, latent, undeveloped immediacy. The bare intrinsic and inherent essence of an object. Für sich is a greater, developed intensity of immediacy; an object genuinely independent either of consciousness or of other things; something for itself. In and for itself belongs to the Absolute alone. Its asserted independence is the developed result of its nature and as a system of internal relations it is independent of external relations. -- H.H.
Incomplete symbol: A symbol (or expression) which has no meaning in isolation but which may occur as a constituent part in, and contribute to the meaning of, an expression which does have a meaning. Thus -- as ordinarily employed -- a terminal parenthesis ) is an incomplete symbol, likewise the letter λ which appears in the notation for functional abstraction (q. v.), etc.

An expression A introduced by contextual definition -- i.e., by a definition which construes particular kinds of expressions containing A, as abbreviations or substitutes for certain expressions not containing A, but provides no such construction for A itself -- is an incomplete symbol in this sense. In Principia Mathematica, notations for classes, and descriptions (more correctly, notations which serve some of the purposes that would be served by notations for classes and by descriptions) are introduced in this way by contextual definition. -- A. C.

Whitehead and Russell, Principia Mathematica, vol. 1.

Inconceivability: The property of being something that is unthinkable. Having self-contradictory properties such that mental representation is impossible. In metaphysics, Herbert Spencer's criterion of truth, that when the denial of a proposition is incapable of being conceived the proposition is to be accepted as necessary or true. Syn. with Inconceptible. -- J.K.F.
Inconsistency: As applied to logistic systems, the opposite of consistency (q. v.).

A set of propositional functions is inconsistent if there is some propositional function such that their conjunction formally implies (see Logic, formal, § 3) both it and its negation.

A set of sentences is inconsistent if there is some sentence A such that there is a valid inference from them to A and also from them to ∼A.

If the notion of possibility is admitted, in the sense of a modality (see Modality, and Strict implication), a set of propositions may be said to be inconsistent if their conjunction is impossible. -- A.C.

Incontinence: (Gr. akrasia) Moral condition of a person unable to control his bodily desires by rational principles. The incontinent man is distinguished from the licentious in that in the one case there is a conflict between bodily desires and rational choice and in the other case not (Aristotle). -- G.R.M.
Indefinite potentiality, error of: Inadequate analysis of causation. -- H.H.
Independence: In a set of postulates for a mathematical discipline (see Mathematics), a particular postulate is said to be independent if it cannot be proved as a consequence of the others. A non-independent postulate is thus superfluous, and should be dropped.

In a logistic system (q. v.), a primitive formula or a primitive rule of inference may be said to be independent if there are theorems of the system which would cease to be theorems upon omission of the primitive formula or primitive rule of inference. -- A.C.

Indeterminism: (Lat. in + determinatus, pp. of determinare) Theory that volitional decisions are in certain cases independent of antecedent physiological and psychological causation. See Free-Will, Determinism. -- L.W.
Index: (Lat. indicare, to indicate) A directing sign; that which indicates. Employed by C. S. Peirce (1839-1914) in logic, or semiotic, as that sign which refers to an object by virtue of being affected by it. See Sign. -- J.K.F.
Indian Aesthetics: Art in India is one of the most diversified subjects. Sanskrit silpa included all crafts, fine art, architecture and ornament, dancing, acting, music and even coquetry. Behind all these endeavors is a deeprooted sense of absolute values derived from Indian philosophy (q.v.) which teaches the incarnation of the divine (Krsna, Shiva, Buddha), the transitoriness of life (cf. samsara), the symbolism and conditional nature of the phenomenal (cf. maya). Love of splendour and exaggerated greatness, dating back to Vedic (q.v.) times mingled with a grand simplicity in the conception of ultimate being and a keen perception and nature observation. The latter is illustrated in examples of verisimilous execution in sculpture and painting, the detailed description in a wealth of drama and story material, and the universal love of simile. With an urge for expression associated itself the metaphysical in its practical and seemingly other-worldly aspects and, aided perhaps by the exigencies of climate, yielded the grotesque as illustrated by the cave temples of Ellora and Elephanta, the apparent barbarism of female ornament covering up all organic beauty, the exaggerated, symbol-laden representations of divine and thereanthropic beings, a music with minute subdivisions of scale, and the like. As Indian philosophy is dominated by a monistic, Vedantic (q.v.) outlook, so in Indian esthetics we can notice the prevalence of an introvert unitary, soul-centric, self-integrating tendency that treats the empirical suggestively and by way of simile, trying to stylize the natural in form, behavior, and expression. The popular belief in the immanence as well as transcendence of the Absolute precludes thus the possibility of a complete naturalism or imitation. The whole range of Indian art therefore demands a sharing and re-creation of absolute values glimpsed by the artist and professedly communicated imperfectly. Rules and discussions of the various aspects of art may be found in the Silpa-sastras, while theoretical treatments are available in such works as the Dasarupa in dramatics, the Nrtya-sastras in dancing, the Sukranitisara in the relation of art to state craft, etc. Periods and influences of Indian art, such as the Buddhist, Kushan, Gupta, etc., may be consulted in any history of Indian art. -- K.F.L.
Indian Ethics: Ethical speculations are inherent in Indian philosophy (q.v.) with its concepts of karma, moksa, ananda (q.v.). Belief in salvation is universal, hence optimism rather than pessimism is prevalent even though one's own life is sometimes treated contemptuously, fatalism is embraced or the doctrine of non-attachment and desirelessness is subscribed to. Social institutions, thoughts, and habits in India are interdependent with the theory of karma and the belief in universal law and order (cf. dharma). For instance, caste exists because dharma is inviolable, man is born into his circumstances because he reaps what he has sown. Western influence, in changing Indian institutions, will eventually also modify Indian ethical theories. All the same, great moral sensitiveness is not lacking, rather much the contrary, as is proven by the voluminous story and didactic fable literature which has also acted on the West. Hindu moral conscience is evident from the ideals of womanhood (symbolized in Sita), of loyalty (symbolized in Hanuman), of kindness to all living beings (cf. ahimsa), of tolerance (the racial and religious hotchpotch which is India being an eloquent witness), the great respect for the samnyasin (who, as a member of the Brahman caste has precedence over the royal or military). Critics confuse -- and the wretched conduct of some Hindus confirm the indistinction -- practical morality with the fearless statements of metaphysics pursued with relentless logic "beyond good and evil."

Periods of despondency and inactivity or even degenency and depravity in India have kept pice with disastrous political developments. But a joy in life's pursuits is evident from the earliest Vedic period and is to be traced in the multifariousness of Indian culture and the colorful Indian history itself which has left the Hindus one of the ancient races still virile among nations and capable of assimilation without itself becoming extinct. Happiness may be enjoyed even in the severest penance and asceticism for which India is noted, while a certain concomitant heroism seems undeniable.

The ethical teachings of the Bhagavad Gita (q.v.). of the various religio-philosophical groups, of the Buddhists and Jainas of Greater India, are high; but if such ideals have not been attained generally in practice, or even if repulsive and cruel rituals and linga worship are prevalent, such phenomena are understandable if we consider the 340 millions of teeming humanity within the fold of Hinduism, from aborigines to a Gandhi, Tagore, and Sir Raman. Treatises dealing with practical morality are very numerous. They may be classed into those of a purely religious leaning among which we might count all religio-philosophical literature of the Vedic and non-Vedic tradition, including drama and epic literature, and those that deal specifically with practices of the nature of self-culture (cf. Yoga), religious observances (sacrifice, priest-craft, rites, ceremonies, etc.), household affairs and duties (Grhyasutras), and the science of polity and government (Arthasastras). -- K.F.L..

Indian Philosophy: General name designating a plethora of more or less systematic thinking born and cultivated in the geographic region of India among the Hindus who represent an amalgamation of adventitious and indigenous peoples, but confined at first exclusively to the caste-conscious Indo-germanic conquerors of the lands of the Indus and Ganges. Its beginnings are lost in the dim past, while a distinct emergence in tangible form is demonstrable from about 1000 B.C. Hindu idiosyncrasies are responsible for our inability to date with any degree of accuracy many of the systems, schools, and philosophers, or in some cases even to refer to the latter by name. Inasmuch as memory, not writing, has been universally favored in India, an aphoristic form (cf. sutra), subtended by copious commentaries, give Indian Philosophy its distinctive appearance. The medium is Sanskrit and the dialects derived from it. There are translations in all major Asiatic and European languages. The West became familiar with it when philologists discovered during last century the importance of Sanskrit. As a type of thinking employing unfamiliar conceptions and a terminology fluctuating in meaning (cf., e.g., rasa), it is distinct from Western speculations. Several peaks have been reached in the past, yet Indian Philosophy does not cease to act fructifyingly upon the present mind in India as elsewhere. Various factions advance conflicting claims as to the value of Indian speculation, because interpretations have not as yet become standardized. Textual criticism is now making strides, but with varying successes. Among larger histories of Indian Philosophy may be mentioned those of Deussen, Das Gupta, Bel-valkar and Ranade, and Radhakrishnan.

Philosophic speculations, heavily shrouded by "pre-logical" and symbolic language, started with the poetic, ritualistic Vedas (q.v.), luxuriating in polytheism and polyanthropoism, was then fostered by the Brahman caste in treatises called Aranyakas (q.v.) and Brahmanas (q.v.) and strongly promoted by members of the ruling caste who instituted philosophic congresses in which peripatetic teachers and women participated, and of which we know through the Upanishads (q.v.). Later, the main bulk of Indian Philosophy articulated itself organically into systems forming the nucleus for such famous schools as the Mimamsa and Vedanta, Sankhya and Yoga, Nyaya and Vaisesika, and those of Buddhism and Jainism (all of which see). Numerous other philosophic and quasi philosophic systems are found in the epic literature and elsewhere (cf., e.g., Shaktism, Shivaism, Trika, Vishnuism), or remain to be discovered. Much needs to be translated by competent philosophers.

All Indian doctrines orient themselves by the Vedas, accepting or rejecting their authority. In ranging from materialism to acosmism and nihilism, from physiologism to spiritualism, realism to idealism, monism to pluralism, atheism and pantheism, Hindus believe they have exhausted all possible philosophic attitudes (cf. darsana), which they feel supplement rather than exclude each other. A unnersal feature is the fusion of religion, metaphysics, ethics and psychology, due to the universal acceptance of a psycho-physicalism, further exemplified in the typical doctrines of karma and samsara (q.v.). Rigorous logic is nevertheless applied in theology where metaphvsics passes into eschatology (cf., e.g., is) and the generally accepted belief in the cyclic nature of the cosmos oscillating between srsti ("throwing out") and pralaya (dissolution) of the absolute reality (cf. abhasa), and in psychology, where epistemology seeks practical outlets in Yoga (q.v.). With a genius for abstraction, thinkers were and are almost invariably hedonistically motivated by the desire to overcome the evils of existence in the hope of attaining liberation (cf. moksa) and everlasting bliss (cf. ananda, nirvana). -- K.F.L.

Indifferents: (Gr. adiaphora) In Stoic ethics those things which are in themselves neither good nor bad, as producing neither virtue nor vice; such as life, health, pleasure, beauty, wealth, noble birth, and their contraries. The Stoics further distinguished between indifferents that are to be preferred (proegmena) and those that are not to be preferred (apoproegmena). The former, though not goods, have a certain value and are the objects of natural inclination. -- G.R.M.
Indirect proof: See Reductio ad absurdum.
Indiscernibles, Principle of: (Lat. indiscernibilis, indistinguishable) In the philosophy of Leibniz (Monadology, IX, Nouv. Essais, II, 22), no two monads can be exactly alike. -- V.J.B.
Individual: In formal logic, the individuals form the first or lowest type of Russell's hierarchy of types. In the Principia Mathematica of Whitehead and Russell, individuals are "defined as whatever is neither a proposition nor a function." It is unnecessary, however, to give the word any such special significance, and for many purposes it is better (as is often done) to take the individuals to be an arbitrary -- or an arbitrary infinite -- domain, or any particular well-defined domain may be taken as the domain of individuals, according to the purpose in hand. When used in this way, the term domain of individuals may be taken as synonymous with the term universe of discourse (in the sense of Boole) which is employed in connection with the algebra of classes. See Logic, formal, §§ 3, 6, 7. -- A.C.
Individualism: The doctrine that emphasizes the reality of the individual and concrete. Differs from Personalism (q.v.) -- R.T.F.

In political philosophy, the doctrine that the state exists for the individual, not vice versa. In political economy, laissez faire system of competition.

Individual Psychology: (a) In the widest sense, individual psychology is one of the major departments of psychology, comparable to such other major subdivisions as experimental psychology, abnormal psychology, comparative psychology, etc. It is the branch of psychology devoted to the investigation of mental variations among individuals and includes such topics as: character and temperament (see Characterology) mental types, genius, criminality, intelligence, testing, etc. Attention was frst directed to individual differences by Francis Galton (Hereditary Genius, 1869). Galton's method was applied to mental deficiency by Dugdale (The Jukes, 1877) and Galton himself extended the same type of inquiry to free association and imagery in Inquiries into Human Faculty, 1883. A more recent contribution to individual psychology is Cattell's American Men of Science (1906).

(b) In a somewhat more restricted sense, individual psychology, in contrast to folk psychology, group psychology or social psychology is the investigation of the individual considered -- so far as possible -- apart from the influence of the social group of which he is a member,

(c) Finally the term "individual" psychologv has been appropriated by a special school of analytic psychology (see Psychoanalysts), namely that of Alfred Adler. See A. Adler, Problems of Neurosis; E. Wexberg, Individual Psychology. -- L.W.

Individuation: The constitution of a reality as a singular member of a species. In the context of the matter and form theory it is difficult to explain how either prime matter (which is in itself the same in all physical things), or substantial form (which is the same in all members of the same species), can be the cause or principle of individuality. See Thomism, Scotism, Suarezianism, for various explanations. -- V.J.B.
Indriya: (Skr.) One of five or more sensory functions or "senses", conceived generally in Indian philosophy kinetically as powers subservient to manas (q.v.). A common division is into the quintads of karmendriyas (q.v.) and jnanendriyas (s.v.). -- K.F.L.
Induction: (Lat. in and ducere, to lead in) i.e., to lead into the field of attention a number of observed particular facts as ground for a general assertion. "Perfect" induction is assertion concerning all the entities of a collection on the basis of elimination of each and every one of them. The conclusion sums up but does not go beyond the facts observed. Ordinarily, however, "induction" is used to mean ampliative inference as distinguished from explicative, i.e , it is the sort of inference which attempts to reach a conclusion concerning all the members of a class from observation of only some of them. Conclusions inductive in this sense are only probable, in greater or less degree according to the precautions taken in selecting the evidence for them. Induction is conceived by J. S. Mill, and generally, as essentially an evidencing process; but Whewell conceives it as essentially discovery, viz., discovery of some conception, not extracted from the set of particular facts observed, but nevertheless capable of "colligating" them, i.e., of expressing them all at once, (or, better stated, of making it possible to deduce them). For example, Kepler's statement that the orbit of Mars is an ellipse represented the discovery by him that the conception of the ellipse "colligated" all the observed positions of Mars. Mill's view of induction directly fits the process of empirical generalization; that of Whewell, rather the theoretical, explanatory part of the task of science. Charles Peirce, viewing induction as generalization, contrasts it not only with inference from antecedent to consequent ("deduction") but also with inference from consequent to antecedent, called by him "hypothesis" (also called by him "abduction" (q.v.), but better termed "diagnosis). -- C.J.D.
Induction, complete or mathematical: See Recursion.
In esse, in intellects in re: Medieval Latin expressions of which the first signifies, in being, in existence, the second, in the intellect, especially as a general idea formed by the process of abstraction, the third, in a really existing thing outside the mind. One may add that in the matter of is the commonly known signification of the third. -- J.J.R.
Inference: (Lat. in + ferre, to bear) The process of reasoning whereby starting from one or more propositions accepted as true, the mind passes to another proposition or propositions whose truth is believed to be involved in the truth of the former. Inference is a psychological process connecting propositions asserted to be true and is to be distinguished from implication, the logical relation which holds between the same propositions when the inference is valid. An inference is valid when a genuine implicative relation holds between the propositions, invalid when there is no such implicative relation. Inference is deductive or inductive according as the underlying logic is deduction (see Deduction) or induction (see Induction). W. B. Joseph, An Introduction to Logic. L. S. Stebbing, Modern Introduction to Logic. J. Cook Wilson, Statement and Inference. B. Bosanquet, Implication and Linear Inference. -- L.W.

See Logic, formal and Valid inference.

In fieri: (in Scholasticism) A thing is said to be in fieri when it is beginning to be, but is not yet complete. It is said to be in facto when it exists completely in the nature of things with those constituent parts with which it remains. Thus a picture is in fieri, when the painter is painting the canvas, but it is said to be in facto when the picture has already been painted. -- H.G.
Infima species: The lowest species of a classification. In Aristotle, the individual. -- R.B.W.
Infinite: Opposite of finite (q. v.), as applied to classes, cardinal and ordinal numbers, sequences, etc. See further Cardinal number; Limit. -- A.C.
Infinitesimal: In a phraseology which is logically inexact but nevertheless common, an infinitesimal is a quantity, or a variable, whose limit is 0. Thus in considering the limit of f(x) as x approaches c, if this limit is 0 the "quantity" f(x) may be said to be an infinitesimal; or in considering the limit of f(x) as x approaches 0, the "quantity" x may be said to be an infinitesimal. (See the article limit.) -- A.C.
Infinity: An endless extent of space, time, or any series. Is usually conceived negatively, as having no termination; may be conceived positively, in respect to reality as actually extending without end. -- R.B.W.
Infinity, axiom of: See Logic, formal, §§ 6, 9.
Ingression: According to A. N. Whitehead, participation of potentialities in the creation of complex actualities; "a concretion -- that is, a growing together -- of diverse elements." -- R.B.W.
Innate Ideas: (Lat. innatis, inborn) The power of understanding given in the very nature of mind. Such ideas are spoken of as a priori. Ideas which are inborn and come with the mind at birth, such as God or immortality. More generally, ideas which all men as human and rational, necessarily and universally possess.

Locke's arguments against Descartes' belief in innate ideas (cf. Essay on the Human Understanding, bk. I) were the target of Leibniz's Nouveaux Essais, 1701 (publ. in 1765). -- M.F.

Innatism: (Lat. in + natus, inborn) A theory of philosophy in which ideas, or principles, are considered to be present in the mind at birth, either fully formed or requiring some additional experience for their complete formulation. -- V.J.B.
Inner sense: The capacity of feeling immediately, (i.e. unconditioned by the knowledge of principles, causes, or advantages) the beauty and harmony (or their opposites) of material objects. (Francis Hutcheson.) -- K.E.G.
Innervation, Sensation of: (Lat. in + nervus, nerve) Sensation accompanying the efferent nerve currents which discharge from the central nervous system into the muscles. The existence of such a sensation has been much disputed by psychologists. (See W. James, The Principles of Psychology, Vol. II, pp. 498 ff.) -- L.W.
Insolubilia: See Paradoxes, logical.
Inspection: (Lat. inspection, from inspectus, pp. of inspicere, to look into) Rudimentary knowledge of qualities and relations between qualities as given in immediate experience, (see Presentational Immediacy) in contradistinction to perception, memory, introspection and other higher cognitive processes which are conversant not with qualities but with objects. -- L.W.
Institutions: (Lat. instituere, to cause to stand)

(a) Establishments. Relatively permanent group behavior patterns or established social practices, as distinguished from temporary practices or patterns.

(b) Socially established behavior patterns, authoritatively or legally enforced, as distinguished from Folkways which are merely taken-for-granted common but uncompelled ways of behavior and as distinguished from ''mores" which are enforced by group opinion rather than by legally authorized meant. -- A.J.B.

Instrumentalism: See Pragmatism.
Instrumental theory: The mind is a substance existentially independent of the body, either existing prior to the body, or after the destruction of the body. (Broad.) -- H.H.
Instrumental value: See Value, Instrumental.
Integral: A whole composed of parts. Belonging to a whole as one of its parts. Anything composed of distinguishable parts. Complete, untouched. In mathematics, related to integers, the result of integration. -- J K.F.
Integration: (Lat. integrare, to make whole) The act of making a whole out of parts. In mathematics, a limiting process which may be described in vague terms as summing up an infinite number of infinitesimals, part of the calculus. In psychology, the combination of psycho-physical elements into a complex unified organization. In cosmology, the synthetic philosophy of Spencer holds that the evolutionary process is marked by two movements: integration and differentiation. Integration consists in the development of more and more complex organizations. Inverse of: differentiation (q.v.). -- J.K.F.
Intellect: (Lat. intellects from intellegere, to understand) The cognitive faculty of the mind as it operates at higher abstract and conceptual levels. -- L.W.

St. Augustine distinguished the intellect from reason, aliud est intellectus, aliud ratio. Intellection would be impossible without reason: Intelligere non valemus, nisi ralionem habeamus. The intellect is the soul itself: Non enim aliquid aliud est quam anima, sed aliquid animae est intellectus. It rules the soul: Intellectus animam regit, ad ipsam animam pertinens. Sometimes the intellectus is called intelligentia. Both the intellect and reason are innate in the mind, mens cui ratio et intelligentia naturaliter inest. Reason seeks knowledge or science, scientia, while the intellect, which is higher, aims at wisdom, sapientia, or the contemplation of eternal things, and especially God. -- J.J.R.

Whence, in the typical Scholastic or medieval notion, intellect is an immaterial faculty of the soul, that is, its operations are performed without a bodily organ, though they depend on the body and its senses for the material from which they receive their first impulse. Nothing is in the intellect that has not been previously in the senses. The impressions received by the external senses are synthesized by the internal sensus communis which forms an image or phantasm; the phantasm is presented to the intellect by imagination, memory and the vis cogitativa co-operating. The internal senses are conceived as being bound to organic functions of the brain. The intellect operates in a twofold manner, but is only one. As active intellect (intellectus agens) it "illuminates" the phantasm, disengaging there from the universal nature; as passive intellect (int. possibilis) it is informed by the result of this abstractive operation and develops the concept. Concepts are united into judgments by combination and division (assertion and negation). Judgments are related to each other in syllogistic reasoning or by the abbreviated form of enthymeme. Aquinas denies to the intellect the capacity of becoming aware of particulars in any direct way. The intellect knows of them (e.g. when asserting: Socrates is a man) only indirectly by reflecting on its own operations and finally on the phantasm which served as starting point. Propositions, however, have no directly corresponding phantasm. Later Scholastics credit the intellect with a direct knowledge of particulars (Suarez). See Abstraction, Faculty. -- R.A.

Intellectualism: (aesthetics) a. The "Intellectual Principle" is supreme beauty (Plotinus).

b. "Intellectual Intuition" turned objective is esthetic intuition (Schelling). -- L.V.

Intellectual virtues: See Dianoetic virtues.
Intelligence: (Lat. intelligent, from intellegere, to understand) The capacity of the mind to meet effectively -- through the employment of memory, imagination and conceptual thinking -- the practical and theoretical problems with which it is confronted. Intelligence is more inclusive than intellect which is primarily conceptual. See Intellect.

In Dewey (q.v.), intelligence is the basic instrument, to be contrasted with fixed habit, traditional customs, and the sheer force of political or bureaucratic power as means of settling social issues. -- L.W.

Intelligence, creative: A term denoting the presence of self-consciousness, self-direction and purpose in the creative processes of the world. Syn. in Personalism for God, elan vital, but in naturalism of Dewey, divorced from such associttion. -- R.T.F.
  1. Understandable; comprehensible; knowable; meaningful;
  2. Orderly; logical; coherent; rational;
  3. Communicable; expressible;
  4. Having unity of principle; capable of complete rational explanation or understanding; capable of causal explanation;
  5. Clear to natural or pure reason; apprehensible by the intellect (q.v.) only as against apprehensible through the senses; conceptual as against perceptual; conceptually describable or explainable;
  6. Capable of being known synoptically or as it is in itself or in essence; capable of being known through itself as against by agency of something else; graspable by in tuition, self-explanatory;
  7. Capable of being appreciated or sympathized with;
  8. Super-sensible; of the nature of mind, reason, or their higher powers. .
-- M.T.K
Intension and extension: The intension of a concept consists of the qualities or properties which go to make up the concept. The extension of a concept consists of the things which fall under the concept; or, according to another definition, the extension of a concept consists of the concepts which are subsumed under it (determine subclasses). This is the old distinction between intension and extension, and coincides approximately with the distinction between a monadic proposittonal function (q. v.) in intension and a class (q. v.). The words intension and extension are also used in connection with a number of distinctions related or analogous to this one, the adjective extensional being applied to notions or points of view which in some respect confine attention to truth-values of propositions as opposed to meanings constituting propositions. In the case of (interpreted) calculi of propositions or propositional functions, the adjective intensional may mean that account is taken of modality, extensional that all functions of propositions which appear are truth-functions. The extreme of the extensional point of view does away with propositions altogether and retains only truth-values in their place. -- A.C.

The Port-Royal Logic, translated by T. S. Baynes (see Introduction by the translator).

Lewis and Langford, Symbolic Logic, New York and London, 1952. R. Carnap, The Logical Syntax of Language, New York and London, 1937.

Intensive quantity: Any quantity which is such that there exists no known physical process of addition by which a greater quantity of the kind in question could be produced from a lesser quantity; opposed to extensive quantity (q.v.). -- A.C.B.
Intent: (Lat. intensus, pp. of intendere, to stretch) The act of directing the mind towards an object. See Intentionality. -- L.W.
Intention: In Scholastic logic, first intentions were properties or classes of, and relations between, concrete things. Second intentions were properties or classes of, and relations between, first intentions.

This suggests the beginning of a simple hierarchy of types (see Logic, formal, § 6), but actually is not so, because no "third intentions" were separated out or distinguished from second. Thus the general concept of class is a second intention, although some particular classes may also be second intentions.

Thomas Aquinas (q. v.) defined logic as the science of second intentions applied to first intentions. -- A. C.

Intentionalism: Theory of mind and knowledge which considers intentionality a distinctive if not the defining characteristic of mind and the basis for mind's cognitive and conative functions. See Intentional Theory of Mind. -- L.W.
Intentionality: (Lat. intentio, from intendere, to stretch) The property of consciousness whereby it refers to or intends an object. The intentional object is not necessarily a real or existent thing but is merely that which the mental act is about. Intentionality is the modern equivalent of the Scholastic intentio. -- L.W.

(Ger. Intentionalität) In Husserl:

  1. (broadest sense) The character of anything as "intending" or pointing beyond itself, self-transcendence.
  2. (most frequent sense) The character of consciousness as pointing; beyond itself, as consciousness of something, and as having its horizon of co-intendings: noetic intentionality.
  3. The character of an object other than consciousness itself as pointing beyond itself, e.g., to its objective background or to something that it represents or indicates: objective intentionality.
  4. The character of a modality as pointing back to the original of which it is intrinsically a modification.
See phenomenology. -- D.C.
Intentionally: (in Scholasticism) Same as mentally. -- H.G.
Intentional Theory of Mind: The definition of mind in terms of intentionality (See Intentionality) which originated in the Scholastic doctrine of intentio, was revived by F. Brentano (Psychologie vom empirischen standpunkte, 1874) though his influence has become a characteristic theory of German phenomenology. See Phenomenology. -- L.W.
Interactionism: See Interaction Theory.
Interaction Theory: (Lat. inter + actio, action) A dualistic theory of the body-mind relation, advanced by Descartes (1596-1650), which asserts a two directional causal influence between mind and body. See Mind-Body Relation. -- L.W.
Interest: (Lat. interest, it concerns, 3rd pers. sing, of interesse, to be between) The characteristic attitude of the mind toward any object which attracts and absorbs its attention. See Attention. -- L.W.
Internal: Inside a thing (or person). Of the thing itself. The relation of part to whole or of whole to part.
  1. In logic: compare intension.
  2. In metaphysics: the doctrine of internal relations, that all relations are internal, that is, monism.
  3. In epistemology: subjective. Opposite of external.
-- J.K.F.
Interoceptor: See Receptor.
Intersubjective: Used and understood by, or valid for different subjects. Especially, i. language, i. concepts, i. knowledge, i. confirmability (see Verification). The i. character of science is especially emphasized by Scientific Empiricism (q. v., I C). -- R.C.
Intersubjective cognition: See Intersubjective Intercourse.
Intersubjective intercourse: (Lat. inter + subiectus) Knowledge by one subject of another subject or the other's conscious states. (See J. Ward, Naturalism and Agnosticism, pp. 164-70). -- L.W.
Intra-ordinal Laws: Connecting properties of aggregates of the same order. Laws connecting the characteristics of living organisms. (Broad.) -- H.H.
Intrinsic: (Lat. inter, between + secus, beside) Having internal value. Value in the relation of parts to whole. -- J.K.F.
Intrinsic goodness: The property of being good in itself or good as an end (and not as a means merely) or desirable for its own sake. Sometimes identified with the property of being desired for its own sake. According to G. E. Moore a thing is intrinsically good if it would be good even if it existed quite alone. -- W.K.F.
Introception: (in Personalism) The coalescence of the world of objective values with his own substance by which a person attains reality. -- R.T.F.
Introjection: (Lat. intro. within + jacere, to throw) In Epistemology, theory of the knowledge process, that objects of knowledge are represented in consciousness by images. A name given by R. Avenarius (1843-1896) to the doctrine of perception which he rejected. The doctrine of representative perception. In psychology, the ascription to material objects of some of the properties of life. More specifically, in psycho-analysis, the act of absorbing other personalities into one's own, of assuming that external events are internal. Opposite of: projection. -- J.K.F.

Epistemological theory of Descartes, Locke, Berkeley that the individual mind is confined to the circle of its ideas, and that it cognizes an external world and other minds only by an outward projection of its inner representations. The term was employed by Avenarius, (Kritik der reinen Erfahrung, 1888) who criticized the theory and proposed as an alternative his own theory of pure experience which emphasizes the essential solidarity between knowing subject and object known and has been introduced into English philosophy by Ward, Stout and others. -- L.W.

Introspection: (Lat. intro, within + spicere, to look) Observation directed upon the self or its mental states and operations. The term is the modern equivalent of "reflection" and "inner sense" as employed by Locke and Kant. Two types of introspection may be distinguished: (a) the direct scrutiny of conscious states and processes at the time of their occurrence (See Inspection), and (b) the recovery of past states and processes by a retrospective act. -- L.W.
Introspectionism: The standpoint in psychology which advocates the employment of the introspective method. -- L.W.
Introspective Method: The method in psychology, which, in opposition to the objective method of Behaviorism (See Behaviorism) relies largely upon introspective observation. See Introspection. -- L.W.
Intuitio: A term generally employed by Spinoza in a more technical sense than that found in the Cartesian philosophy (see Reg. ad Dir. Ing., III). It is primarily used by Spinoza in connection with "scientia intuitiva" or knowledge "of the third kind" (Ethica, II, 40, Schol. 2). Intuition of this sort is absolutely certain and infallible, in contrast to reason (ratio, q.v.), it produces the highest peace and virtue of the mind (Ibid, V, 25 and 27). Also, as over against ratio, it yields an adequate knowledge of the essence of things, and thus enables us to know and love God, through which knowledge (Ibid, V, 39) the greater part of our mind is rendered eternal. -- W.S.W.
Intuition: (Lat. intuere, to look at) The direct and immediate apprehension by a knowing subject of itself, of its conscious states, of other minds, of an external world, of universals, of values or of rational truths. -- L.W.
Intuitionism (mathematical): The name given to the school (of mathematics) founded by L. E. J. Brouwer (q. v.) and represented also by Hermann Weyl, Hans Freudenthal, Arend Heyting, and others. In some respects a historical forerunner of intuitionism is the mathematician Leopold Kronecker (1823-1891). Views related to intuitionism (but usually not including the rejection of the law of excluded middle) have been expressed by many recent or contemporary mathematicians, among whom are J. Richard, Th. Skolem, and the French semi-intuitionists -- as Heyting calls them -- E. Borel, H. Lebesgue, R. Baire, N. Lusin. (Lusin is Russian but has been closely associated with the French school.)

For the account given by Brouwerian intuitionism of the nature of mathematics, and the asserted priority of mathematics to logic and philosophy, see the article Mathematics. This account, with its reliance on the intuition of ordinary thinking and on the immediate evidence of mathematical concepts and inferences, and with its insistence on intuitively understandable construction as the only method for mathematical existence proofs, leads to a rejection of certain methods and assumptions of classical mathematics. In consequence, certain parts of classical mathematics have to be abandoned and others have to be reconstructed in different and often more complicated fashion.

Rejected in particular by intuitionism are

  1. the use of impredicative definition (q. v.);
  2. the assumption that all things satisfying a given condition can be united into a set and this set then treated as an individual thing -- or even the weakened form of this assumption which is found in Zermelo's Aussonderungsaxiom or axiom of subset formation (see logic, formal, § 9);
  3. the law of excluded middle as applied to propositions whose expression lequires a quantifier for which the variable involved has an infinite range.

As an example of the rejection of the law of excluded middle, consider the proposition, "Either every even number greater than 2 can be expressed as the sum of two prime numbers or else not every even number greater than 2 can be expressed as the sum of two prime numbers." This proposition is intuitionistically unacceptable, because there are infinitely many even numbers greater than 2 and it is impossible to try them all one by one and decide of each whether or not it is the sum of two prime numbers. An intuitionist would accept the disjunction only after a proof had been given of one or other of the two disjoined propositions -- and in the present state of mathematical knowledge it is not certain that this can be done (it is not certain that the mathematical problem involved is solvable). If, however, we replace "greater than 2" by "greater than 2 and less than 1,000,000,000," the resulting disjunction becomes intuitionistically acceptable, since the number of numbers involved is then finite. The intuitionistic rejection of the law of excluded middle is not to be understood as an assertion of the negation of the law of excluded middle; on the contrary, Brouwer asserts the negation of the negation of the law of excluded middle, i.e., ∼∼[p ∨ ∼p]. Still less is the intuitionistic rejection of the law of excluded middle to be understood as the assertion of the existence of a third truth-value intermediate between truth and falsehood.

The rejection of the law of excluded middle carries with it the rejection of various other laws of the classical propositional calculus and functional calculus of first order, including the law of double negation (and hence the method of indirect proof). In general the double negation of a proposition is weaker than the proposition itself; but the triple negation of a proposition is equivalent to its single negation. Noteworthy also is the rejection of ∼(x)F(x) ⊃ (Ex)∼F(x); but the reverse implication is valid. (The sign ⊃ here does not denote material implication, but is a distinct primitive symbol of implication.) -- A.C.

L. E. J. Brouwer,
De onbetrnuwhaarheid der logische principes, Tijdsdschrift voor Wijsbegeerte, vol 2 (1908), pp 152-158; reprinted in Brouwer's Wiskunde. Waarheid, Werketijkhetd. Groningen, 1919.
L. E. J. Brouwer,
Intuitionism and formalism. English translation by A. Dresden. Bulletin of the American Mathematical Society, vol. 20 (1913), pp 81-96.
H. Weyl,
Consistency in mathematics. The Rice Institute Pamphlet, vol 16 (1929), pp 245-265.
A. Heyting,
Mathematische Grundlagen-forschung, Intuitionismus, Beweistheorie, Berlin, 1934.

Intuitionism (philosophical):

(1) In general: any philosophy in which intuition is appealed to as the basis of knowledge, or at least of philosophical knowledge.

(2) In ethics:

  1. in the narrower traditional sense, intuitionism is the view that certain actions or kinds of action may be known to be right or wrong by a direct intuition of their rightness or wrongness, without any consideration of the value of their consequences. In this sense intuitionism is opposed to utilitarian and teleological ethics, and is most recently represented by the neo-intuitionists at Oxford, H. A. Prichard, E. F. Carritt, W. D. Ross. It is sometimes said to involve the view that the organ of ethical insight is non-rational and even unique. It takes, according to Sidgwick, three forms. Perceptual intuitionism holds that only judgments relating to the rightness or wrongness of particular acts are intuitive. Dogmatic intuitionism holds that some general material propositions relating to the rightness or wrongness of kinds of acts may also be intuited, e.g. that promises ought to be kept. Philosophical intuitionism holds that it is only certain general propositions about what is right or wrong that are intuitive, and that these are few and purely formal.
  2. In the wider more recent sense, intuitionism includes all views in which ethics is made to rest on intuitions, particular or general, as to the rightness, obligatoriness, goodness, oi value of actions or objects. Taken in this sense, intuitionism is the dominant point of view in recent British ethics, and is represented in Europe by the phenomenological ethics of M. Scheler and N. Hartmann, having also proponents in America. That is, it covers not only the deontological intuitionism to be found at Oxford, but also the axiological and even teleological or utilitarian intuitionism to be found in J. Martineau, H. Sidgwick, H. Rashdall, G. E. Moore, J. Laird. Among earlier British moralists it is represented by tho Cambridge Platonists, the Moral Sense School, Clarke, Cumberland, Butler, Price, Reid, Whewell, etc.By saying that the basic propositions of ethics (i.e. of the theory of obligation, of the theory of value, or of both) are intuitive, the intuitionists mean at least that they are ultimate and underivative, primitive and uninferable, as well as synthetic, and sometimes also that they are self-evident and a priori. This implies that one or more of the basic notions of ethics (rightness, goodness, etc.) are indefinable, i.e. simple or unanalysable and unique; and that ethics is autonomous. Intuitionists also hold that rightness and goodness are objective and non-natural. Hence their view is sometimes called objectivism or non-naturalism. The views of Moore and Laird are also sometimes referred to as realistic.

See Deontological ethics, Axiological ethics, Teleological ethics, Utilitarianism, Objectivism, Realism, Autonomy of ethics, Non-naturalistic ethics. -- W.K.F.

Intuitive cognition: Intuitive cognition is the apprehension of an object (e.g. the hearing of a bell) in contrast to thinking about an object (e.g. "thinking about a bell"). (See C. D. Broad, The Mind and its Place in Nature, p. 144.) See Acquaintance, Knowledge by. -- L.W.
Invariant: A constant quantity. In mathematics, a quantity which remains the same under a group of transformations. -- J.K.F.
Invention: As a practical activity is distinguished from creation as an artistic activity. -- L.V.
Irregularity, (Theory of): In art as in nature all beauty is irregular (Renoir).- -- L.V.
Irrelevant: Not bearing upon, or logically related to, the point under discussion, or the case in hand. -- G.R.M.
Irony, Socratic: See Socratic method.
Is, Isa, Isana, Isvara: (Skr.) "Lord", an example of the vacillating of Indian philosophy between theology and metaphysics. They often use such theistic nomenclature for the Absolute without always wishing to endow it as such with personal attributes except as may be helpful to a lower intelligence or to one who feels the need of worship and bhakti (q.v.). -- K.F.L.
Islam: Name peculiar to the religion founded by Mohammed, embracing all sects found among his followers. Etymologically the term means "to resign oneself". The word means not fatalistic submission to the deity, but striving after righteousness, the practice of the law, obedience to rules and formal performance of outward duties. Meaning the acceptance of the divine will, Islam stresses the legal and external performance of religion. -- H.H.
Isolation by Varying Concomitants: In the logic of scientific method, the fourth of the five experimental methods of J. S. Mill (1806-1873), whereby cause can be determined in an actual case. Known also as the Method of Concomitant Variation. Stated by Mill as follows: "Whatever phenomenon varies in any manner whenever another phenomenon varies in some particular manner, is either a cause or an effect of that phenomenon, or is connected with it through some fact of causation". -- J.K.F.
Isomorphism: (Gr. isos, equal + morphe, form) Similarity of structure. In Gestalt psychology, structural similarity between fields in the brain and the content of consciousness.

In logic and mathematics, a relation between two systems such that there exists a one-one correspondence between their elements, and an identity of some relation that holds between any of the elements in one system and the corresponding elements in the other system. -- J.K.F.

I Yuan: The One-Prime which is the supreme beginning. It is One and is identical with the Origin. "The Prime is the root of the myriad things, in which there is also the origin of Man." (Tung Chung-shu, 177-104 B.C.) -- W.T.C.