takes place in nature?" or, in the latter case, "What are the properties of a circle?"
But the idea of an ought or of duty indicates a possible action, the ground of which is a pure conception; while the ground of a merely natural action is, on the contrary, always a phenomenon. This action must certainly be possible under physical conditions, if it is prescribed by the moral imperative ought; but these physical or natural conditions do not concern the determination of the will itself, they relate to its effects alone, and the consequences of the effect in the world of phenomena. Whatever number of motives nature may present to my will, whatever sensuous impulses—the moral ought it is beyond their power to produce. They may produce a volition, which, so far from being necessary, is always conditioned—a volition to which the ought enunciated by reason, sets an aim and a standard, gives permission or prohibition. Be the object what it may, purely sensuous—as pleasure, or presented by pure reason—as good, reason will not yield to grounds which have an empirical origin. Reason will not follow the order of things presented by experience, but, with perfect spontaneity, rearranges them according to ideas, with which it compels empirical conditions to agree. It declares, in the name of these ideas, certain actions to be necessary which nevertheless have not taken place and which perhaps never will take place; and yet presupposes that it possesses the faculty of causality in relation to these actions. For, in the absence of this supposition, it could not expect its ideas to produce certain effects in the world of experience.
Now, let us stop here and admit it to be at least possible that reason does stand in a really causal relation to phenomena. In this case it must—pure reason as it is—exhibit an empirical character. For every cause supposes a rule, according to which certain phenomena follow as effects from the cause, and every rule requires uniformity in these effects; and this is the proper ground of the conception of a cause—as a faculty or power. Now this conception (of a cause) may be termed the empirical character of reason; and this character is a permanent one, while the effects produced appear, in conformity with the various conditions which accompany and partly limit them, in various forms.
Thus the volition of every man has an empirical c
