Section One The ideal in general.

We have seen above that no objects at all can be represented through pure concepts of the understanding without any conditions of sensibility, because the conditions for the objective reality of these concepts are lacking, and nothing is encountered in them except the pure form of thinking. Nevertheless they can be exhibited in concreto if one applies them to appearances; for in the latter they have the proper material for a concept of experience, which is nothing but a concept of the understanding in concreto. Ideas, however, are still more remote from objective reality than categories; for no appearance can be found in which they may be represented in concreto. They contain a certain completeness that no possible empirical cognition ever achieves, and with them reason has a systematic unity only in the sense that the empirically possible unity seeks to approach it without ever completely reaching it.

But something that seems to be even further removed from objective reality than the idea is what I call the ideal, by which I understand the idea not merely in concreto but in individuo, i.e., as an individual thing which is determinable, or even determined, through the idea alone.