THE SOURCES OF A PRIORI KNOWLEDGE: A COMMENTARY ON KANT'S NOTIONS OF SENSIBILITY, UNDERSTANDING, AND REASON

In this dissertation I investigate what Kant identifies in the Prolegomena to Any Future Metaphysics as the sources of our a priori knowledge--namely, sensibility, understanding, and reason. After a brief introductory chapter, the purpose of chapter two, "Kant's Given," is to determine the character of the objects of sensibility. On this issue hinges the question of what Kant means when he calls himself a transcendental idealist. To provide a context for my explication of Kant's refutation of idealism, I introduce his account of ordinary idealism and take up his own special version of idealism. Kant's refutation of idealism depends on establishing a necessary interrelationship between our intuitions of space and time; this is done wholly in terms of the formal characteristics of space and time, without reference to Kant's discussion of our capacity (receptivity) for receiving representations. The final section of chapter two deals with Kant's discussion of receptivity and the spontaneity that must be combined with it in order for cognition to take place.;Chapter three turns to the sources of a priori knowledge in mathematics and natural science. Robert Paul Wolff, in his study Kant's Theory of Mental Activity, provides a convenient foil for this discussion; his reading of Kant's regressive method in the Prolegomena leads Wolff to interpret the conditions of knowledge in a way that, I think, is mistaken and obscures Kant's solution to the problem of how synthetic judgments in mathematics and natural sciences are possible a priori. I also argue that Kant's treatment of the understanding as a source of knowledge is a reply of Hume's scepticism with respect to causality.;Chapter four explicates Kant's claim that reason is our highest faculty "for elaborating the matter of intuition and bringing it under the highest unity of thought." To accomplish this requires distinguishing between the unity of understanding ("the unity of appearances by means of rules") and the unity of reason ("the unity of the rules of understanding under principles"). Fundamental to an understanding of the function of reason of Kant's view is his discussion of the conditions of thought; I undertake to provide this understanding through an examination of the logical apparatus that underlies the origination of the transcendental ideas of reason, as Kant explains and defends that apparatus in both the Logic and the Critique of Pure Reason. Chapter four concludes with a discussion of the transcendental ideas insofar as they guide our investigation of the three kinds of relations which, Kant argues, "are to be universally found in all our representations"--namely, relation to the subject, relation to objects as appearances, and relation to objects in general.;In chapter five I examine the work of Thomas Kuhn and discuss some points of agreement and disagreement between Kant's thought and Kuhn's methodological and historiographic discoveries, including some treatment of implications of Kant's thought, as explicated in the present study, for issues that Kuhn raises in the philosophy of science. This contrast with Kuhn points up the fundamentally philosophical character of Kant's notions of sensibility, understanding, and reason as the sources of our a priori knowledge.