charming to the affections, every one may readily perceive with the least exertion of his reason, if it be not wholly spoiled for abstraction.

The question then is this: “Is it a necessary law for all rational beings that they should always judge of their actions by maxims of which they can themselves will that they should serve as universal laws?” If it is so, then it must be connected (altogether a priori) with the very conception of the will of a rational being generally. But in order to discover this connexion we must, however reluctantly, take a step into metaphysic, although into a domain of it which is distinct from speculative philosophy, namely, the metaphysic of morals.

In a practical philosophy, where it is not the reasons of what happens that we have to