its internal possibility a reference to purposes, — i.e. to be possible only as a natural purpose, and without the causality of the concepts of rational beings external to itself, — then it is requisite secondly that its parts should so combine in the unity of a whole that they are reciprocally cause and effect of each other’s form.

Only in this way can the Idea of the whole conversely (reciprocally) determine the form and combination of all the parts; not indeed as cause — for then it would be an artificial product — but as the ground of cognition, for him who is judging it, of the systematic unity and combination of all the manifold contained in the given material.

For a body then which is to be judged in itself and its internal