Certainty

[L:78] Kant distinguishes empirical and rational certainty, mediated and immediate certainty, original and derivative certainty, and intuitive and discursive certainty. He claims that all knowledge must involve certainty, defined generally as the consciousness of necessity, and in particular that speculative knowledge is either mathematical knowledge (which has intuitive certainty) or philosophical (which has discursive certainty). Among philosophical certainty is rational and both empirical and historical certainty; everyday empirical knowledge has one of the latter certainties, although it is hard to understand Kant's notion of non-rational certainty. In the Critique, Kant distinguishes the certainty of moral knowledge from both philosophical and mathematical certainty.