Has Kant Answered Hume

The reason Kant made a distinction between two sources of knowledge — understanding and intuition was because we are finite beings who do not have an intellectual intuition. So, simply from our concepts we cannot draw any conclusions about existence (as we do in the Ontological Argument) without the aid of sensible intuition. The issue here is that this seems to saddle us with a new kind of dualism — of concepts and reality. Kant admits that these two apparently distinct sources of knowledge could have an identical root, but this root remains incomprehensible for us. So we have to accept this duality from our finite perspective.

The Jewish philosopher Solomon Maimon argued that this duality is fatal to the prospects of Kant answering Hume. In principle, Hume would have no problem in conceding that there are a priori concepts of understanding that determine the possibility of experience by organising the sensible matter of cognition. The issue is that this matter itself does not have a conceptual/rational structure; a conceptual framework is superimposed on it. If the matter of cognition itself were conceptual, then understanding must have an a priori conceptual cognition of objects of intuition. This is lacking because, as we see, for instance, in the case of a child, he learns the proposition ‘fire burns’ through experience rather than an a priori cognition that informs him before the experience of touching fire that fire and heat are in a causal relation. That understanding lacks an a priori cognition of sensible truths that it has in the case of, say, mathematical truths, implies that understanding cannot justify that the sensible domain falls within its jurisdiction, allowing understanding to act as the lawgiver and solve the quid juris problem. Consequently, a synthetic truth is grasped a posteriori and not a priori; to solve the Humean problem, one has to show that there can be an a priori cognition of synthetic truths — that there is a synthetic a priori where the a priori concept does not determine only the form but also the matter of cognition. (This is somewhat of a simplification of Maimon’s argument, in which, by reframing the issue, we can have a priori cognition of sensible truths but not a pure cognition, which is what is required to answer Hume.)