For a thing to be a natural purpose in the first place it is requisite that its parts (as regards their being and their form) are only possible through their reference to the whole. For the thing itself is a purpose and so is comprehended under a concept or an Idea which must determine a priori all that is to be contained in it.

But so far as a thing is only thought as possible in this way, it is a mere work of art; i.e. a product of one rational cause distinct from the matter (of the parts), whose causality (in the collection and combination of the parts) is determined through its Idea of a whole possible by their means (and consequently not through external nature).

But if a thing as a natural product is to involve in itself and in