Immanuel Kant begins his work, Groundwork of the Metaphysic of Morals, by dividing human knowledge into three branches: logic; physics; and ethics (Kant, 1956). He further divides ethics (which relates indirectly to reason), into empirical knowledge, and a priori knowledge (Kant, 1956). With reference to ethical behavior, the first term applies to sensuous experience, and the second to some inborn intrinsic knowledge. By making these distinctions Kant immediately alerts the reader that he finds morality and ethics to be metaphysical in nature. In other words, he finds some human concepts are simply consistent within themselves and must be excepted as such. For Kant, then, ethics, and therefore reason, are part of the human condition and have certain qualities that are consistent within themselves. These qualities deal with practicality, purity, and the role of reason (Kant, 1956).
Having already established that ethics and reason are metaphysical in nature, Kant sets about looking for intrinsic consistent features. He begins by separating the concept of a pure moral philosophy from anthropological concerns. By this he is stating that shared habit patterns, modes of communication, and ways of viewing each other do not contain the pure elements that a priori knowledge, or a shared empirical knowledge must have. In Kant's words, referring to man: "but he has not so easily the power to realize the Idea in concreto in his conduct of life" (Kant, 1956, p. 57).
Kant has established that practical knowledge, and thus practical reason, is different from other kinds of knowledge in that it is based on the parts of human experience that can be felt first hand, and acted upon with a priori knowledge. This constitutes, in Kant's view, a kind of purity that is indisputable. If morals and ethics comprise a portion of Kant's Metaphysic, -- an understanding and acceptance that a consistent thread probably guides all of us during mor...