Kant's Refutation of Idealism

Kant's Refutation of Idealism ERLING SKORPEN I PROBABLY MOST CONTEMPORARYSTUDENTS Of Kant's Critique of Pure Reason ask themselves as have students in .the past, whether in his Refutation I of the idealism of Descartes and Berkeley he does not also refute himself. For in this Refutation Kant argues that self-knowledge is impossible without simultaneous knowledge of the external physical world. So the question arises, if he is right, whether the outside world necessary to self-knowledge does not consist of just those things-in-themselves he said could never be known other than they exist as the indescribable source of uninterpreted sense-data. A look at some of Kant's commentators shows that opinion varies whether Kant does effectively contradict himself in this Refutation. It appears to H. A. Prichard that Kant does, while scoring effectively against Descartes.2 But to N. Kemp Smith it seems that the apparent inconsistency only firms up the difference between Kant's phenomenalism and Berkeley's, Kant's emerging as quite consistent and sound,s To H. J. Paton it also seems that the problems raised by the Refutation, while serious, could possibly be treated consistently with Kant's overall position by distinguishing between momentary and present sense-data, on the one hand, and sense-data united by Kant's a pr/or/rules of synthesis, on the other. The latter might well constitute the kind of externalized and permanent physical objects required by Kant's "turning of the tables" on Descartes.4 Similarly , E. Cassirer has no doubts that Kant "turns the game of idealism back on material idealism" without demonstrating "the existence of things-in-themselves as some have strangely taken it on occasion." 5 In developing the issue anew, these reactions to Kant's Refutation will be further clarified and contrasted, which I hope to follow by fresh criticism and insight . But let us first look briefly at the Refutation itself. It is an attempt to show that empirical knowledge of the self presupposes knowledge of an outside world to which we have access in perception and which is known "immediately" by us. Such an attempt is clearly contrary to Descartes' contention that we never perceive the external physical world directly, but only infer its existence from and partial resemblance to our sensory ideas, taking any correspondence between the two on faith alone. 1Kritik der reinen Vernun]t (2nd ed.; Hamburg, 1956), pp. 272f. Eng. trans, by N. Kemp Smith, Immanuel Kant s Critique o] Pure Reason (London, 1950),pp. 244f. 2H, A. Prichard, Kant's Theory o] Knowledge (1909),p. 323. SN. Kemp Smith, A Commentary on Kant's Critique o] Pure Reazon (2nd ed.; New York, 1950),pp. 313f. 4H. J. Paton, Kant's Metaphysic of E~perience (London, 1951),II, 380f. E. Casslrer,Das Erkenntn~Troblem (Berlin, 1907),II, 582f.Trans. my own. [23] 24 HISTORY OF PHILOSOPHY Kant begins his argument by saying that self-knowledge is essentially knowledge of the historicity of the self. We have knowledge of past and present experiences and of experiences to come, and the sum of our recollections, present experiences, and anticipations constitutes in large part or altogether our empirical knowledge of ourselves. Our sense of self-identity is itself bound up with this temporal understanding of ourselves. That is why, in further confirmation of Kant's point, modem psychoanalysis has been able to show that without such time-orientation with respect to self-knowledge, the sense we have of ourselves would be severely disrupted and perhaps destroyed altogether. This sense is intimately biographical, which in turn is intimately historical, and we are familiar enough with what happens to victims of simple amnesia. On this Kantian point, therefore, scarcely anyone would disagree, including the Cartesians among us. Kant next observes that the time-bound awareness of self "presupposes something permanent in perception." Here too he seems to be on firm ground. Talk of past events in our lives relative to the present and future, such as our knowing that we were born so many years ago in a certain city, while we now reside in perhaps another city and expect to for some time to come, is presumably...