Page:Critique of Pure Reason 1855 Meiklejohn tr.djvu/551

 cognition, and is termed Critical Philosophy; or it is, secondly, the system of pure reason—a science containing the systematic presentation of the whole body of philosophical knowledge, true as well as illusory, given by pure reason—and is called Metaphysic. This name may, however, be also given to the whole system of pure philosophy, critical philosophy included, and may designate the investigation into the sources or possibility of a priori cognition, as well as the presentation of the a priori cognitions which form a system of pure philosophy—excluding, at the same time, all empirical and mathematical elements.

Metaphysic is divided into that of the speculative and that of the practical use of pure reason, and is, accordingly, either the Metaphysic of Nature, or the Metaphysic of Ethics. The former contains all the pure rational principles—based upon conceptions alone (and thus excluding mathematics)—of all theoretical cognition; the latter, the principles which determine and necessitate a priori all action. Now moral philosophy alone contains a code of laws—for the regulation of our actions—which are deduced from principles entirely a priori. Hence the Metaphysic of Ethics is the only pure moral philosophy, as it is not based upon anthropological or other empirical considerations. The metaphysic of speculative reason is what is commonly called metaphysic in the more limited sense. But as pure Moral Philosophy properly forms a part of this system of cognition, we must allow it to retain the name of Metaphysic, although it is not requisite that we should insist on so terming it in our present discussion.

It is of the highest importance to separate those cognitions which differ from others both in kind and in origin, and to take great care that they are not confounded with those with which they are generally found connected. What the chemist does in the analysis of substances, what the mathematician in pure mathematics, is, in a still higher degree, the duty of the philosopher, that the value of each different kind of cognition, and the part it takes in the operations of the mind, may be clearly defined. Human reason has never wanted a Metaphysic of some kind, since it attained the power of thought, or rather of reflection; but it has never been able to keep this sphere of thought and cognition pure from all admixture of foreign elements. The idea of a science of this kind