"Everyone must admit that if a law is to have moral force, i.e. to be the basis of an obligation, it must carry with it absolute necessity; that, for example, the precept, `Thou shalt not lie,"' is not valid for men alone, as if other rational beings had no need to observe it; and so with all the other moral laws . . .; that, therefore, the basis of obligation must not be sought in the nature of man ["anthropology"], or in the circumstances in the world in which he is placed, but a priori simply in the conception of pure reason . . ." (IP3 588a)