Moreover, the reality we apprehend is not reality in itself. It is merely our experience or "take" on it. Kant's startling claim is that we have no basis for assuming that a material perception of reality ever resembles reality itself. I can tell if my daughter's drawing of her teacher looks like the teacher by placing the portrait alongside the person. With my eyes, I compare the copy with the original. Kant points out, however, that comparing our experience of reality to reality itself is impossible. We have representations only, never the originals. So we have no basis for presuming that the two are even comparable. When we equate experience and reality, we are making an unjustified leap.
It is essential to recognize that Kant isn't diminishing the importance of experience. It is entirely rational for us to use science and reason to discover the operating principles of the world of experience. This world, however, is not the only one there is. Kant contended that while science and reason apply to the world of sensory phenomena, of things as they are experienced by us, science and reason cannot penetrate what Kant termed the noumena – things as they are in themselves.
Some critics have understood Kant to be denying the existence of external reality or of arguing that all of reality is "in the mind." Kant emphatically rejects this. He insists that the noumenon obviously exists because it is what gives rise to phenomena. In other words, our experience is an experience of something. Perhaps the best way to understand this is to see Kant as positing two kinds of reality: the material reality that we experience and reality itself. To many, the implication of Kant's argument is that reality as a whole is, in principle, inaccessible to human perception and human reason.
So powerful is Kant's argument here that his critics have been able to answer him only with derision, as though his arguments are self-evidently fallacious. When I challenged Daniel Dennett to debunk Kant's argument, he responded on his website by saying several people had already refuted Kant. But he didn't provide any refutations and he didn't name any names. Basically, Mr. Dennett was relying on the ignorance of the audience. In fact, there are no such refutations.