Kant's Metaphysical Deduction and the Intellectual Origin of the Categories

Abstract

Hume famously argues that we have no idea of objectively necessary connections between existents. But in his metaphysical deduction of the categories, Kant seeks to vindicate our right to use the categories to think of such connections. Kant holds that certain acts of the understanding make judgments possible. For example, the judgment “If the sun shines, then the stone warms up” is made possible by thinking of the constituent judgments using the hypothetical form of judgment. The judgment “The sun warms the stone” is made possible by thinking of the perceived sun and stone using the category CAUSE. My dissertation offers a novel account of how the logical forms of judgment and the categories relate. I argue that the same logical functions of the understanding make possible both the use of the logical forms of judgment and of the categories. The logical functions are reflective activities through which the mind combines representations according to certain rules. For example, the ground-consequence function, through which the mind combines representations by treating some as grounded on others, is exercised both when the mind combines conceptual representations using the hypothetical form (“If the sun shines, then the stone warms up”) and when it combines perceptual representations using the category of CAUSE (“The sun warms the stone”). My dissertation generalizes this interpretation, offering a systematic account of the origin of each logical form and category. Based on this account, I offer a unique interpretation of the metaphysical deduction and show how Kant legitimizes the use of the categories in thinking.