provide a motive and bring about an interest which may be called purely moral; or, in other words, how it is that Pure Reason can be practical; — to explain this problem, all human reason is inadequate, and all trouble and work spent on it are vain.” Now it should be remembered that, if any one asserts the existence of a thing which cannot even be conceived as possible, it is incumbent ou him to prove that it is an actual reality; whereas the Categorical Imperative of Practical Reason is expressly not put forward as a fact of consciousness, nor otherwise founded on experience.

Rather are we frequently cautioned not to attempt to explain it by having recourse to empirical anthropology. (Cf. e.g., p. vi. of the preface; R., p. 5; and pp. 59, 60; R., p. 52). Moreover, we are repeatedly (e.g., p.