known by the reason. And this reason is limited and has a definite structure. So whatever is not fitted into that structure is not knowable by that reason. I tried to map that structure in my first and most important work, The Critique of Pure Reason, and thus limit the borders of possible human knowledge more severely than had been done before. SOCRATES: It seems, then, that you limited human knowledge even more than Hume did, and that you were therefore even more of a skeptic than he was. He believed