Curt Ducasse, Philosophy as a Science, 1941
CHAPTER NINE
The Subject Matter of the Natural, the Formal, and the Mental Sciences
IN THE light of the conclusions reached in the preceding chapter, the problem of defining the subject matter distinctive of the natural sciences as a group is now seen to reduce to that of identifying the sort of facts primitive for these sciences.
I. The Subject Matter Distinctive of the Natural Sciences. -- I submit that the primitive facts of the natural sciences are any facts ascertainable by ordinary external perception; that is, any facts susceptible of being perceptually public in the sense that ordinary perceptual observation is what establishes them as beyond question for all the practitioners of those sciences. That it is facts of this sort which originate and also terminate inquiry in the case of physics is obvious from an examination of the examples of primitive facts of this science that have been given; and the case is the same with the primitive facts of the other natural sciences. All these sciences both start from and in the last resort appeal to "observation" or "experience", and in their case this observation or experience is observation of the ordinary, externally perceptual kind, for only facts susceptible of being observed in this way are susceptible of being directly identified or observed by several persons, that is, are susceptible of being observationally public.
That facts of the perceptually public kind are those with which natural scientists start, and to which they ultimately appeal as verificatory or confutative, is widely recognized among them, and on occasion they themselves explicitly declare it. As clear-cut a statement of this sort as I have found would be the following "An essential characteristic of all facts admitted to the body of scientific knowledge is that they are public. Science demands public rather than private facts. . . . Science deals only with those aspects of nature which all normal men can observe alike."{1} Another statement substantially to the same effect is the following: "The subject matter of science may be defined as those immediate judgements concerning which universal agreement can be obtained."{2} But what the practitioners of the natural sciences do testifies even more eloquently than what they say that the facts which for them are primitive in the sense we have assigned to that term are facts of the perceptually public kind.
This does not mean, however, that anything to which ordinary external perception may appear to testify is necessarily accepted as a primitive fact by natural science, for there are such things as perceptual illusions, and even perhaps also collective hallucinations. We can hardly engage here in a discussion of the difference between veridical and non- veridical perception, but it must be pointed out at least that although in given cases we may doubt the factuality of what perceptual observation appears to reveal, we cannot doubt it in every case without wholly depriving the natural sciences of their subject matter.
The reason for this is that there is no such thing as a problem or question without data. The data of a problem are the facts it is about, and to say that a problem which is not just hypothetical but categorical is about facts perceptually public is to say that these facts are given categorically and not just hypothetically. If in a given case the data of the problem turn out not to be facts, but to have been only erroneously believed to be facts, then in that case no categorical problem is left, but, if any at all, only a speculative one.{3}
In the light of these considerations, I submit that we may now conclude that nature -- which is the subject matter of the natural sciences as a group consists of such facts as are susceptible of being perceptually public, plus such facts as are analytically or synthetically implicit in these.
2. The Subject Matter Distinctive of the Formal Sciences. -- The distinction between primitive and derivative facts applies to the formal sciences as well as to the natural, but the primitive facts of the formal sciences are of a different sort.
The facts to which these sciences ultimately appeal, and with which they start, are always of the nature of prescriptive verbal definitions, or postulates, or rules of formation or transformation. These obviously are not facts which the logician or mathematician finds, but facts which he creates by means of stipulations or prescriptions. But the primitives of the formal sciences do not include all facts so created. For example, that a given child's name is John is a fact created by his parents through a prescriptive act, but the fact so created does not belong to pure logic, since it contains as a constituent the child himself, who is not a logical entity but a physical one of flesh and blood. The prescription that creates a fact of this sort may be describes as a rei-verbal one, and the prescription, of the converse sort, by which for instance the inhabitants of a city assign an incumbent to the description "mayor of the city" may be called a verbo-real prescription. As distinguished from either of these, the prescriptions which create the primitive facts of the formal sciences always are of the verbo-verbal sort. That is, the primitive facts of these sciences are created, by means of stipulations, wholly out of what we may call discursive or verbal entities.
Discursive entities are any entities fulfilling the following conditions:
1. They are susceptible of being readily uttered, whether vocally, graphically, or otherwise, that is, they are such that a perceptible utterance of them can ordinarily be caused by the mere wish.
2. They are recognizable as the same in the various utterances of them, whether these be graphic, vocal or other; or we may put this also by saying that their various utterances are recognizable as "equal."{4}
3. They are entities the utterances of which are always man-caused, artifactual -- never, or virtually never, caused by natural events independently of the activity of man.{5}
It is wholly immaterial to the problems of the pure formal sciences whether the discursive entities of which they make use do or do not symbolize or stand for entities other than discursive. The postulates, definitions, and rules they take as their primitive facts can therefore be any whatever that they please.{6} A limitation upon the possibility of completely arbitrary choice of such primitives enters only when pragmatic considerations are introduced, that is, when applicability of the calculus based on the primitives to the solution of problems concerning entities other than those of the given calculus is a desideratum.
The derivative facts of the formal sciences, which we may call their theorems (as distinguished from their definitions, postulates, and rules), consist of the expressions that may be derived from such primitives by means of the very rules these primitives include.
The knowledge given us by the formal sciences is a priori knowledge because the truth-value of their propositions is determined wholly by prescription. But although in all cases their truth-value is so determined, knowledge of their truth-value may be direct or indirect. It is direct whenever we are laying down the postulates, definitions, or rules, but it is only indirect in the case of the theorems, since their truth-value, although implicit in that of those primitives, becomes known to us only in so far as we discover it through deduction of the theorems from the primitives.
3. The Subject Matter of the Mental Sciences. -- As stated above when we listed the sciences to be designated respectively as natural, formal, and mental, the latter comprise psychology of the genuinely introspective sort, and other sciences, if any, which also take as their primitives the facts revealed by introspection, but which ask about them questions going beyond those that have usually been considered under the heading of "introspective psychology." The derivative facts of the science of mind will, like those of any other science, be facts analytically or synthetically implicit in its primitives, that is, they will consist of relations in which the primitives stand to one another. To clarify the scope of the science of mind as distinguished from that of what has gone by the name of "introspective psychology," it is necessary to point to some questions, traditionally considered by psychologists of the introspectionist school, which do not strictly belong to the science of mind; and to some questions, not usually considered by these psychologists, which nevertheless do belong to it
4. Some Questions Dealt with by "Introspectionists" Not within the Scope of the Science of Mind. -- An idea of the sorts of facts that introspective psychologists have brought to light may be gained by examination of such a textbook as that of the late Edward B. Titchener, who may be taken as a representative introspectionist. We notice first that the larger portion of its contents is not concerned with the analysis or synthesis of introspectables, i. e., with investigation of the relations of introspectables to one another, but, with the physical conditions under which certain kinds of introspectable facts -- chiefly sensations -- occur. Although it is very useful for purposes of introspective study to know these physical conditions, so that we may reproduce at will the introspectables depending on them which we desire to study, discovery of these physical conditions is of course strictly speaking no part of the task of introspective psychology but of psychophysics or psychophysiology. The content of a science of mind, as represented by the pages devoted to introspective psychology proper in Titchener's textbook, would be rather meager, for about all it would include would be an inventory of the kinds of sensations and other mental states, an account of certain of the elements and dimensions of some complex kinds of mental states, and an account of the general laws in accordance with which mental elements become discriminated or submerged, dissociated or associated. As Titchener himself suggests, a science of mind limited to this "would stand to scientific psychology very much as the old-fashioned natural histories stand to modern textbooks of biology."{7} A scientific psychology, he declares, must not only describe but also explain.
5. Artificial Limitations of the Scope of the Science of Mind. -- However, without mentioning any other ground than that "with change of our surroundings, entirely new consciousnesses may be set up," Titchener sweepingly asserts that "we cannot regard one mental process as the cause of another mental process." And since he also assumes, without argument, that we cannot "regard nervous processes as the cause of mental processes," he concludes that explanation of mental processes consists in tracing correspondences between them and nervous processes: "The nervous system does not cause, but it does explain mind. lt explains mind as the map of a country explains the fragmentary glimpses of hills and rivers and towns that we catch on our journey through it."{8} I submit first that if this is explanation at all, which is very questionable, it is certainly not explanation in the sense in which the term is used in the other sciences, where it means either the tracing of effects to their causes, or the deduction of known empirical laws from theoretical constructs. And, second, the search for correlations between psychical and physiological processes is in any case not introspective psychology but, as already pointed out, psychophysiology.
Further, as regards Titchener's assumption that no mental process can cause another nor therefore explain another, I submit that on the contrary such causation is just what we do have in any case of association of ideas. Imagining something, or thinking of something, does in numberless instances cause the occurrence of some other mental event -- of some other image, of the thought of something else, of some emotion or some impulse, etc, as the case may be. The sight or image of a little cross, for example, causes to arise the thought of addition, or of Christianity, or of a crossroad, etc., according to the contextual content of the mind at the time. Thinking of the approach of black clouds causes the thought of rain, and belief that black clouds are approaching causes belief that rain is imminent, etc. The fact that we believe rain to be imminent is properly and adequately explained by the fact that we believe black clouds are approaching, or that we feel rheumatic pains, or that we believe the barometer is falling, etc. Investigation of the associations of ideas habitual to a given mind -- that is, of the ideas regularly caused in it by given ideas -- is what investigation of the given mind chiefly consists in; and establishing valuable connections of this sort between ideas or other kinds of mental states is what constitutes education of a mind. Each such regular connection constitutes a property or law of the mind in which it exists, and it is a part of the task of comprehensive science of mind to investigate minds in respect to such properties.
Titchener's assumption that no mental process can cause another mental process is thus too sweeping. What is true is that mental processes of the kind called sensations are not generally, if ever, directly caused by other mental processes. But the causes of mental processes other than sensations generally are other mental processes (whether themselves sensations or something else). Titchener's assumption therefore constitutes an artificial limitation of the scope of the science of mind.
There is another limitation which introspectionists generally have imposed on that science just as gratuitously, that, namely, introduced by the assumption that there can be no facts in mind other than those introspection can reveal. It is based on the erroneous belief that an "unconscious mental fact" is synonymous with an "unconscious state of consciousness," the latter being obviously a contradiction in terms. As against this, I submit that the mental facts introspection directly discloses are only those that are primitive for the science of mind, and that its derivative facts are discovered not directly by introspective observation but, as in any other science, by analysis and synthesis of the facts observation itself reveals.
To see how arbitrary is the assumption that there can be no facts in mind other than those introspection reveals, we need only consider what would be the parallel assumption in the case of nature. lt would be that there can be no facts in nature other than those susceptible of being perceptually observed. As already pointed out, however, the vast majority of the facts revealed by the natural sciences are not directly perceptible at all. Many of them are accepted as facts, and as facts in nature, only because postulation of them enables us to deduce facts in nature already perceived or laws of nature already discovered inductively, and additional ones that turn out to be verified by further observations of nature. In every property or law, for instance, which, on the basis of observations, we assert as inhering in things, there is an element of postulation just as truly as in our assertions that such entities as atoms or electrons exist; for a statement of the laws or properties of things is not a statement merely of how they have been observed to behave in specified circumstances, but also of how they can be expected to behave again in similar circumstances. But that their behavior will the next time be as before is of course always something that at the given time we have not yet observed but only postulate.
I submit that in the science of mind we have exactly as good a right, and the very same sort of right, to postulate and to call mental certain entities which introspection does not directly disclose at all, but which similarly enable us to deduce facts which introspection has already revealed and additional ones that introspection eventually verifies. Examples of such entities would be the countless opinions, beliefs, mental associations, memories, etc., which all of us have, but of the having which we are totally unconscious at most times. They are properties of our minds, and our minds possess them even at times when they are not introspectively manifest, just as the physical property called combustibility, for instance, is possessed by this sheet of paper even at times, such as the present, when this property is not manifest to perceptual observation. The realm of mind, like that of nature, includes all the facts derivative from its primitives, and thus includes vastly more than is ever directly revealed by observation of it.
6. Gestalt Psychology. -- To what has been said above concerning introspective psychology it must be added that gestalt psychologists question the validity of the sort of introspective analysis which Titchener and others give of, e. g., the perception of distance in terms of doubleness of images, relatively blurred or sharp definition, accommodation sensations, etc. They deny the possibility of analysis of perception into such elements, and phrase their own account in terms of "organization," "forces of organization," "factors of organization," "stresses and strains in a psychophysical field," etc., borrowing the latter concept from physics, and in turn asserting that in physics, as in psychology, fundamental processes are molar rather than molecular. But in view of the insistence of gestalt psychology on the analogy between psychology and physics, and of the indubitable and enormous fruitfulness in the latter of analysis in terms of "molecular" entities such as molecules, atoms, electrons, etc., denial of the possibility, in psychology, of analysis into elementary mental constituents has been one of the most vulnerable points of gestalt psychology. And what it proposes instead is at times hard to distinguish from "explanations" of the automatic and easy type illustrated by the famous example of the viz dormitiva.
The chief contributions of gestalt psychology seem to me, for one thing, its broader conception of introspection as including observation of what it calls the "behavioral environment," i. e., observation of the nature of the environment which at a given time we believe ourselves (whether erroneously or rightly) to be facing. Our "behavioral environment" thus consists of what Broad calls our "epistemological objects" as distinguished from "ontological objects," to which the former may or may not correspond. But perhaps the most significant contribution of gestalt psychology has been its insistence on the importance of wholes of experience, that is, on the importance of the experiential context in which a given bit of experience occurs. The necessity of taking this context into account explicitly would have been obvious from the start to anyone who realized that the causal relation -- whether in a given case its terms happen to be psychical or physical -- is essentially not a two-term but a three-term relation: one term, a given set of circumstances; another term, a given change in them (this change being the cause-event); and the third term, the further change in them (this being the effect-event) resulting from the cause-event. A causal law is thus never, as so often seems to be assumed, of the form "any event of kind C causes an event of kind E," but always of the form "a change of kind C in circumstances of kind K always causes in them a further change of kind E." The taking into account of wholes of experience by gestalt psychology seems to me to amount to introducing into the methodology of introspective psychology the sort of practice which an adequate realization of the general nature of the causal relation would dictate for the methodology of any field where this relation figures.
From the subject matter of, respectively, the natural, the formal, and the mental sciences, let us now pass to that of the philosophical sciences.
[Table of Contents] [Chapter 10]
Notes 1. S. S. Stevens, "The Operational Basis of Psychology," American Journal of Psychology, XLVII (April, 1935), 327. [Back]
2. N. Campbell, Physics, the Elements, p. 21. [Back]
3. Cf. M. Cohen, op. cit., pp. 86 f. [Back]
4. Cf. Carnap, L. S. L., p. 15. [Back]
5. A fuller discussion of discursive entities may be found in "Symbols, Signs, and Signals," loc. cit., pp. 43 ff. [Back]
6. But of course the primitives chosen must be things truly having the nature of postulates, definitions, rules. [Back]
7. A Textbook of Psychology, p. 38. [Back]
8. Ibid., p. 39. [Back]
[Table of Contents] [Chapter 10]