No More Learning

Instead, however, of the deduction of the supreme principle of pure practical reason, that is, the explanation of the possibility of such a knowledge a priori, the utmost we were able to do was to show that if we saw the possibility of the freedom of an           cause, we should also see not merely the possibility, but even the necessity, of the moral law as the supreme practical law of rational beings, to whom we attribute freedom of causality of their will; because both concepts are so inseparably united that we might de- fine practical freedom as independence of the will on anything but the moral law.