The value of any human end is subjective, and yet certain things are necessarily right or wrong. We have certain undeniable obligations of respect to our fellow men; nonetheless, anything that we or they want is only desirable because it is desired, and anyone is at liberty to change his desires. This vital paradox, not yet resolved by moral philosophy, still nourishes life and interest in Kant's moral philosophy. Here I wish to examine his exhilaratingly original solution to this paradox. I shall spend little time on Kant's argument, as I consider it the least impressive part of his performance; rather, I shall examine the principle of his solution. I shall take note of a half-dozen important twentieth-century positions which he has inspired; and I shall point out the direction, largely ignored in modem philosophy, which all this august counsel leads to.
Kant holds that pure practical reason alone can establish an obligation. Only pure reason furnishes the necessity which obligation requires. 1 But because objects of desire are all empirical, none of them can be commanded by pure reason. 2 Our natural desire is happiness; but happiness is an ideal of imagination, not of reason.
What does pure reason command, then? Here it is that Kant makes his perennially fascinating move. Reason commands nothing at all, excepting itself. Why does it command even itself?. Because "nothing can have a value other than that determined for it by the law. The law-making which determines all value must for this reason have a dignity, i.e., unconditioned and incomparable worth. ''3 Why is this exalted law-making identical with reason? Practical reason derives actions from laws -by analogy with theoretical reason, which subsumes knowledge under concepts. 4 The pre-eminent good, then, is to act according to the conception of law; but reason gives no end or interest to be served by this law. All that is left as an end is rationality as such, to be maintained for its own