principles cannot rest upon a ground of explanation of the possibility of a product according to given laws, for the determinant Judgement, but only upon a ground of its exposition for the reflective Judgement. — To explain is to derive from a principle, which therefore we must clearly know and of which we can give an account. No doubt the principle of the mechanism of nature and that of its causality in one and the same natural product must coalesce in a single higher principle, which is their common source, because otherwise they could not subsist side by side in the observation of nature. But if this principle, objectively common to the two, which therefore warrants the association of the maxims of natural investigation depending on both, be such that, though it can be pointed to, it cannot be determinately known nor