indemonstrable concept of Reason. It is assumed of both that they are not generated without grounds, but (according to the above explanation of an Idea in general) in conformity with certain principles of the cognitive faculties to which they belong (subjective principles in the one case, objective in the other).

Concepts of the Understanding must, as such, always be demonstrable [if by demonstration we understand, as in anatomy, merely presentation]; i.e. the object corresponding to them must always be capable of being given in intuition (pure or empirical); for thus alone could they become cognitions. The concept of magnitude can be given a priori in the intuition of space, e.

g. of a right line, etc.; the concept of