Nevertheless, after having so rightly postulated the necessity for a science of the forms of sensation or pure intuition, purely intuitive knowledge, Kant went on, simply because he had no exact idea of the nature of the æsthetic faculty and of art, to fall into an intellectualistic error by reducing the form of sensibility or pure intuition into the two categories or functions of space and time, and by asserting that the spirit emerges from the chaos of sensation by organizing its sensations in space and time.[15] But space and time as such are very far from being primitive categories; they are relatively late and complex formations.[16] As examples of the matter of sensation Kant quoted hardness, impenetrability, colour and so forth. But the mind only recognizes colour and hardness in so far as it has already given form to its sensations; considered as brute matter, sensations fall outside the cognitive spirit, they are a limit; colour, hardness, impenetrability and so on, when recognized, are already intuitions, spiritual elaborations, the æsthetic activity in its rudimentary manifestation. The characterizing or qualifying imagination which is æsthetic activity ought to have occupied in the _Critique of Pure Reason_ the pages devoted to the discussion of space and time, and would thus have constituted a real Transcendental Æsthetic, a real prologue to the transcendental Logic. In this manner Kant would have achieved the truth aimed at by Leibniz and Baumgarten and would have joined hands with Vico. [Sidenote: _Theory of Beauty distinguished by Kant from that of Art._]