"Immanuel Kant's famous Critique of Pure Reason"
Immanuel Kant's Critique of Pure Reason
is one of the best known works of Western philosophy. The point that Pirsig refers to is that of a priori
knowledge. This is Kant's belief that some things are knowable outside of sensory experience. For example, 10 + 11 = 21 is a truth known beyond conscious perception.