Curt Ducasse, Philosophy as a Science, 1941


Philosophy as Identical with Logic

DURING the last hundred years the science of logic has made vastly more progress than it did in all the centuries since its foundation by Aristotle; and today a growing number of mathematicians and philosophers are actively carrying the subject forward. The appearance of Whitehead and Russell's Principia Mathematica in 1910 was one of the outstanding events in the history of its modern development, and among philosophers the question was soon asked what bearings the logical achievements it typified might have upon philosophy. A few years later Russell attempted to answer this question by formulating the conception of the nature of philosophy and of scientific method in philosophy to which he found himself led.{1} It is to the view of the nature and method of philosophy then described by him that we now turn.

I. Russell's Definition of Philosophy. -- "Philosophy," Russell declares, "is the science of the possible."{2} This statement is intended by him to sum up two distinctive characteristics of any philosophical proposition, viz., it must be general, and it must be a priori.

To say that a philosophical proposition must be general means that "it must not deal specially with things on the surface of the earth, or with the solar system, or with any other portion of space and time. . . . A philosophical proposition must be applicable to everything that exists or may exist."{3} Moreover, the view that philosophy is general in this sense is sharply different from the view that it is general in the sense that its propositions have "the universe" or "the whole" as their subject. Russell maintains on the contrary "that there are no propositions of which the 'universe' is the subject; in other words, that there is no such thing as the 'universe'."'{4}

The propositions of philosophy are general, he holds, in the sense that they "may be asserted of each individual thing, such as the propositions of logic," i.e., they formulate "properties which belong to each separate thing, not . . . . properties belonging to the whole of things collectively"{5} and these properties are to be those that belong not only to each separate thing that exists, but to each that may exist.

By saying, on the other hand, that a philosophical proposition must also be a priori, Russell means that it "must be such as can be neither proved nor disproved by empirical evidence." Philosophy "must make only such assertions as would be equally true however the actual world were constituted."{6}

2. Philosophy Indistinguished from Logic. -- But to say that generality and apriority, in the senses defined, constitute the distinctive characteristics of philosophical propositions, is to say that philosophy "becomes indistinguishable from logic as that word has now come to be used."{7} Logic, however, consists of two parts. One is the study of "those general statements which can be made concerning everything without mentioning any one thing or predicate or relation, such for example as: 'If x is a member of the class a and every member of a is a member of b, then x is a member of the class b, whatever x, a, and b may be."{8} This part "merges into pure mathematics, whose propositions all turn out, on analysis, to be such general formal truths."{9}

The other part of logic "is concerned with the analysis and enumeration of logical forms, i.e., with the kinds of propositions that may occur, with the various types of facts, and with the classification of the constituents of facts. In this way logic provides an inventory of possibilities, a repertory of abstractly tenable hypotheses."{10} This second part is philosophically the more important. It "investigates what propositions are and what forms they may have . . . . enumerates the different kinds of atomic propositions, of molecular propositions, of general propositions, and so on."{11}

What Russell regards as included in this second part of logic and therefore of philosophy is made clearer by reference to the meaning he assigns to some of the terms used in his description of that part. By a proposition, for instance, he means "a form of words which must be either true or false."{12} By a fact, he means "that a certain thing has a certain quality, or that certain things have a certain relation."{13} By an atomic proposition, he means one "which expresses . . . . a fact"; by a molecular proposition, one which contains a conjunction, e.g., if, or, and, unless; by a positive general proposition, one containing the word all, e.g., "all men are mortal"; and by a negative general proposition, one containing the word some, e.g., "some men are philosophers."{14}

Since philosophy is declared by Russell to be "indistinguishable from logic" as he conceives the latter, the problems of philosophy, according to the passages cited, are then (1) to discover those "supremely general propositions, which assert the truth of all propositions of certain forms,"{15} and (2) to analyze and enumerate possible logical forms. Thus "every philosophical problem, when it is subjected to the necessary analysis and purification, is found either to be not really philosophical at all, or else to be, in the sense in which we are using the word, logical."{l6}

3. Traditional Metaphysics Not Knowledge but Only Wishful Thinking. -- As indicated by Russell's assertion, above quoted, that there is no such thing as the universe and therefore that no proposition has the universe as subject, metaphysics in the traditional sense of the term is according to him not possible. He considers the building of cosmological systems as no more possible than the discovering of the philosopher's stone, and thinks that philosophy can do nothing whatever to satisfy our hope that the world has this or that desirable ethical character.{17} The systems that have claimed to do this represent, he believes, not knowledge but only the products of wishful thinking. The philosophy that seeks knowledge in a sense of this term as strict as the sense it has when applied to the results of the sciences "must deal with somewhat dry and abstract matters, and must not hope to find an answer to the practical problems of life. . . . . Many hopes which inspired philosophers in the past it cannot claim to fulfill; but other hopes, more purely intellectual it can satisfy more fully than former ages could have deemed possible for human minds."{18}

Unwelcome or even mistaken as this view of metaphysics may be, it is obviously not disposed of by Hoernlé's objection that the method Russell advocates for philosophy imposes upon it a complete reorientation, a new task altogether, and is therefore an instrument for doing well something other than the traditional tasks of philosophy, not a better instrument for doing these.{19} A medieval alchemist might similarly have argued, and with similar irrelevance, that the methods of modern chemistry (had they been described to him) are not better instruments for achieving the traditional tasks of alchemy the distilling of the elixir of life, etc. but only impose upon alchemy a complete reorientation, a new task altogether!

4. Philosophical Method Essentially Analytical. -- Philosophy, Russell declares, "does not become scientific by making use of the other sciences . . . . . Philosophy is a study apart . . . . its results cannot be established by the other sciences, and conversely must not be such as some other science might conceivably contradict."{20} For success in philosophizing, a certain mental discipline is the first requisite. The desire to know philosophical truth must not be obscured by the desire to think we know such truth. It must be strong enough to survive failure after failure to gain the desired knowledge; and it must not be obscured by love of system, or by desire to establish this or that agreeable result. Again, methodological doubt must be practiced in order to loosen the hold of mental habits; and logical imagination must be cultivated to acquire fertility in imagining abstract hypotheses."{21}

When this mental discipline has been acquired, the method of philosophical investigation is found to be essentially analytical. Philosophical problems, as they present themselves, are usually complex and must be analyzed into their component problems. This usually reveals "that a number of . . . . extraordinarily abstract questions underlie any one of the big obvious problems." Eventually a stage is reached where progress requires "some new effort of logical imagination, some glimpse of a possibility never conceived before"; and if this is successful, then "from this point onward, the work of the philosopher is synthetic and comparatively easy."{22}

To illustrate this general description of the process of philosophical discovery, the problem of space as presented in Kant's "Transcendental Aesthetic" may be considered. Russell states that analysis soon shows three distinct problems to be involved. One of them is logical, and is that of the nature of geometrical reasoning; another is physical, namely, that of finding or constructing a physical space having the logical properties of some one of the kinds of space geometry defines; and the third, which is epistemological, is that of showing how synthetic knowledge a priori of space is possible. Of the first, a complete solution is possible, and of the second a solution which is approximate, as are the solutions of other problems in empirical regions. The solution of these two problems has the result of showing that the assumption on which the third is based, viz., that synthetic knowledge a priori of space is possible, is, if not certainly false, at least devoid of the plausibility it had prior to the analysis.{23}

5. Russell's Account of the Nature of Philosophy Incompatible with His Examples. -- The tasks of logic, it will be recalled, are described by Russell as, on the one hand, to discover "certain supremely general propositions, which assert the truth of all propositions of certain forms"; and, on the other hand, to investigate what propositions are and to make an inventory of the possible forms of propositions. Since he declares that when logic means this, philosophy is indistinguishable from logic, these tasks must then also be the tasks of philosophy.

I submit, however, that Russell's account of the process of philosophical discovery, summarized in the preceding sections is an account of the manner of performance of a task other than these; and, further, that both the analytical investigation of the problems of space or of the external world, which Russell offers as illustrations, and likewise the bulk of his other philosophical (vs. purely logical) writings, are examples of attempts to perform tasks other than those of philosophy as he defined them. For to break up some obvious big philosophical problem into its constituent problems e.g., the problem of space as stated by Kant into a logical, a physical, and an epistemological problem and to solve the logical and the physical problems, is something quite different from making an inventory of the possible forms of propositions or of facts, of from classifying the possible constituents of facts, or from discovering supremely general propositions.

To have performed these latter logical tasks puts one in possession of a logical apparatus which may well be of the greatest help, or even indispensable, for the solution of philosophical problems. But the fact remains that to seek such logical apparatus, i.e., to labor at the discovery or at the perfection of it, is one task; whereas to utilize this apparatus, i.e., to labor by means of it at the solution of problems other than logical (such as those of judgment, perception, etc.) is quite another task. The first is the task of logic; but the second is the task of any science for instance of philosophy or of physics for the solution of whose problems a more or less technical logical apparatus needs to be employed. Any science, that is to say, is in some measure applied logic. The subject matter of logic does consist of propositions completely general and a priori. But this is not the case with the subject matter either of philosophy or of any natural science, however much any progress in them may be dependent on possession of an adequate logical equipment. The subject matter of any science other than logic (which includes mathematics) is both specific and empirical.

The point of these remarks may be further emphasized by considering such a presumably philosophical work as Russell's Analysis of Mind This work is not devoted to the question: Which forms of propositions, or types of facts, are possible, and which propositions are supremely general? It is, on the contrary, an attempt to decide whether certain propositions about introspection, belief, truth and falsehood, perception, etc., are certainly or probably true. To decide this, it is no doubt of great help to discern clearly which form, of all those that propositions may have, the propositions considered about these things do have. But even to attempt to discern this is not to labor at a theory of propositions or at an inventory of possible propositional forms. To attempt to decide whether the propositions considered, of which we may have succeeded in discerning the form, are true or false is to labor at still another task, also different from that which Russell describes as the task of logic and of philosophy.

6. Russell's Account of the Nature of Philosophy Unsound. -- But we are then faced with the following choice: either such a work as The Analysis of Mind is not a philosophical work, or else (since it is not a work on logic) philosophy is something distinguishable from logic. I take it that few will have any hesitation in deciding that this work is philosophical, and that philosophy, whether or not it includes logic as a part of itself, is something distinguishable from logic. Russell himself, indeed, at more than one point writes in a way implying the existence of a distinction between philosophy and logic. For instance, he says about the study of logic that "it gives the method of research in philosophy, just as mathematics gives the method in physics" (italics mine).{24} This implies that the study of logic and the study of philosophy are just as distinguishable as in fact are the study of mathematics and the study of physics, even granted that in each case the first is necessary to the second, and that attempts to solve the problems of the second may stimulate us to develop the first.

But if logic is, as giver of method or as instrument, related to philosophy as mathematics is to physics, the conclusion which Russell there draws viz., that "the study of logic becomes the central study in philosophy" certainly does not follow. What does follow, if the alleged parallelism of relation is a fact, is that logic is the central study, not in philosophy, but as equipment for research in philosophy.

7. Differentiation of Philosophy from Logic No Reflection on the Value of the Analytical Method. -- The employability of the analytical method in philosophy is not dependent on the assumption that philosophy is indistinguishable from logic, and the falsity of that assumption therefore has no bearing on the value this method may have there. Whatever conclusion we may eventually reach as to what philosophy essentially is, the employment of the analytical method in it as elsewhere makes for clearness and definiteness; and these are qualities much to be desired in philosophy, since it is in large measure the failure to achieve them that has rendered philosophical investigation so frequently barren. Russell's own use of the analytical method furnishes many convincing examples of its power to bring to light the issues fundamental in various philosophical problems and to define them sharply. Thus, although analysis can hardly be described either as a distinctively philosophical method, or as the whole of the method of philosophy, there can be no doubt that there is in philosophy abundant occasion for employment of it.

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{1} Bertrand Russell, Our Knowledge of the External World (1914); Mysticism and Logic and Other Essays (1919), chap. vi. [Back]

{2} Mysticism and Logic, p. 111. [Back]

{3} Mysticism and Logic, p. 110. [Back]

{4} Mysticism and Logic, p. 110. [Back]

{5} Mysticism and Logic, p. 110 f. [Back]

{6} Mysticism and Logic, p. 111. [Back]

{7} Mysticism and Logic, p. 111. [Back]

{8} Mysticism and Logic, p. 112. [Back]

{9} Our Knowledge of the External World, p. 57. [Back]

{10} Mysticism and Logic, p. 112. [Back]

{11} Our Knowledge of the External World, p. 57. [Back]

{12} Our Knowledge of the External World, p. 52. [Back]

{13} Our Knowledge of the External World, p. 51. [Back]

{14} Our Knowledge of the External World, p. 52 ff. [Back]

{15} Our Knowledge of the External World, p. 57. [Back]

{16} Our Knowledge of the External World, p. 33. [Back]

{17} Our Knowledge of the External World, p. 26. [Back]

{18} Our Knowledge of the External World, p. 29 f. [Back]

{19} Studies in Contemporary Metaphysics, p. 42. [Back]

{20} Our Knowledge of the External World, p. 236 f. [Back]

{21} Our Knowledge of the External World, p. 237. [Back]

{22} Our Knowledge of the External World, p. 241. [Back]

{23} Mysticism and Logic, p. 114-20. [Back]

{24} Our Knowledge of the External World, p. 239.[Back]

[Table of Contents] [Chapter 6]