A good place to start is Kant's antinomies. Basically they are lesson in what goes wrong if you start with the common sense view of reality and then apply it to experience, rather than applying experience to our perception of things. Take the idea of the world. The antinomy is that either in the world every substance is simple or composite, and every composite substance is composed of parts, or there are no composite substances consisting of parts and everything is simple. The solution to this antinomy, as we know, is not to show that one view is false and the other not, but that contained in both is a reification of the idea of the world. The world as a whole is not something that I can experience either as a simple or composite, because it is not a substance at all, but an idea. But if the world is an idea, what kind of idea is it? It is not an idea as essence (as it would be in Plato), but a relation. It precedes the experience of things as such. Each thing I experience is related to another thing and so on, and without this network I would not be able to experience any individual thing, but it itself is not a thing, nor could it ever be a thing. It is the non-perceptible openness in which each thing exists, suspended beyond itself in reaching out to another infinitely. I do not know the world, if you mean by know, experience some thing, rather I have to be it.
