Epistemology

Philosophy in Germany in the late seventeenth and early eighteenth centuries was largely dominated by the legacy of the rationalist philosopher G. W. Leibniz (1646–1716), but by the middle of the eighteenth century German philosophers were increasingly well read in the empiricist philosophy of Locke and Hume. Kant's mature philosophy, advanced in his Kritik der reinen Vernunft (1781, rev. 1787; Critique of pure reason) and presented in a "popular" form in his Prolegomena (1783), is generally thought to be a critical synthesis of these two traditions.

Hume's skeptical worries focused Kant's attention on the nature of scientific knowledge. For Kant, the very idea of such knowledge rests on a presupposition that humans can have cognitive access to laws (as opposed to mere regularities) of nature. Given the viability of scientific knowledge, Kant supposes, one must be in the possession of certain concepts on the basis of which one can combine representations independently of experience. One such concept is "cause and effect." But Hume's attempt to account for the concept of causality within a skeptical, empiricist framework required that he hold that genuine laws of nature are cognitively inaccessible. Hume's skeptical worries, Kant famously remarked, "first interrupted my dogmatic slumber" (Schriften, vol. 4, p. 260); but Hume's skeptical solution was not a happy one for Kant, who never doubted human capacity for genuine scientific knowledge.

In the Critique, Kant is particularly interested in the questionable status of metaphysics as a science. The first words of the book attest to the "peculiar fate" of human reason—namely, that it is compelled to ask questions that are beyond its capacity to answer. Kant principally has in mind the classic questions of metaphysics: for example, whether the soul is simple or composite or whether the world is finite or infinite. Reconceiving of what the proper task of metaphysics should be, Kant takes a cue from the flourishing science of Newtonian physics. But while the goal of physics is to explain some particular array of phenomena, the goal of metaphysics is to give an account of nature as such. For Kant, metaphysics begins with an exhaustive account of human cognitive capacity as the source of the fundamental principles that determine what it is to figure in the domain of nature at all. The main argument of the Critique is a demonstration of the relevant principles, which Kant takes to be the basis of the laws of nature.