, a priori, can not arise technically, from the similarity of the manifold or the contin gent use of cognition in concreto for all sorts of arbitrary external ends, but arises architectonically, for the sake of its affinity and its derivation from a single supreme and inner end, which first makes possible the whole; such a science must be distinguished from all others with certainty and in accordance with principles.b Nobody attempts to establish a science without grounding it on an idea.