In the succeeding exposition of the Kantian philosophy we shall most suitably follow the classification adopted by Kant himself. His principle of classification is a psychological one. All the faculties of the soul, he says, may be referred to three, which are incapable of any farther reduction; knowing, feeling, and desire. The first faculty contains the principles, the governing laws for all the three. So far as the faculty of knowledge contains the principles of knowledge itself, is it theoretical reason, and so far as it contains the principles of desire and action, is it practical reason, while, so far as it contains the principles which regulate the feelings of pleasure and pain, is it a faculty of judgment. Thus the Kantian philosophy (on its critical side) divides itself into three criticks, (1) Critick of pure _i. e._ theoretical reason, (2) Critick of practical reason, (3) Critick of the judgment. I. CRITICK OF PURE REASON.—The critick of pure reason, says Kant, is the inventory in which all our possessions through pure reason are systematically arranged. What are these possessions? When we have a cognition, what is it that we bring thereto? To answer these questions, Kant explores the two chief fields of our theoretical consciousness, the two chief factors of all knowledge, the sensory and the understanding. Firstly: what does our sensory or our faculty of intuition possess apriori? Secondly: what is the apriori possession of our understanding? The first of these questions is discussed in the transcendental _Æsthetics_ (a title which we must take not in the sense now commonly attached to the word, but in its etymological signification as the “science of the apriori principles of the sensory”); and the second in the transcendental _Logic_ or _Analytics_. Sense and understanding are thus the two factors of all knowledge, the two stalks—as Kant expresses it—of our knowledge, which may spring from a common root, though this is unknown to us: the sensory is the receptivity, and the understanding the spontaneity of our cognitive faculty; by the sensory, which can only furnish intuitions, objects become _given_ to us; by the understanding, which forms conceptions, these objects become _thought_. Conceptions without intuitions are empty; intuitions without conceptions are blind. Intuitions and conceptions constitute the reciprocally complemental elements of our intellectual activity. What now are the apriori principles respectively of our knowledge, through the sense and through the thought? The first of these questions, as already said, is answered by