indeed freed ethics from its long tutelage to theology; but he left it still in subjection, subject to his own favorite study, physical science. But though the notion of necessity, together with that of universality, which he derived from physics was employed by him as a fundamental principle of rightness in conduct, the principle itself insensibly, and as it would seem unbeknown to himself, underwent a remarkable change in the course of his undertaking to give it a new application. The following brief comments will serve to elucidate this point. In physics, whenever an antecedent phenomenon has been exactly described, and a sequent phenomenon is defined in the same fashion, the connection is pronounced to be necessary—as for instance the transformation of mechanical energy into heat, and conversely. A single carefully guarded experiment may suffice to establish the necessary nexus between two phenomena. And after having established the necessity, we are confident of the universality. If exceptions should occur and contravene the supposed law, the calculations or the observations are to be corrected. But never in physical science do we start from universality and predict necessity therefrom. Kant in his ethics invariably couples together the two terms Universal and Necessary. But he reverses the procedure of science, he _begins with the universality and thereupon affirms the necessity_. Universality is for him the test of moral necessity. If an act can be universalized, the performance of it, according to him, is morally necessary. For instance, the question is asked, Is it right to kill? Look at the act of killing, says Kant, and see whether it can be universalized, that is to say, whether if everybody felt at liberty to kill, the act of the murderer would or would not be self-defeating? He kills in order to affirm his life at the expense of another’s. If his action were to be generally imitated, his own life would be forfeit, or at least in danger, and he would be annulling what he intends to affirm. Hence murder is morally wrong: to sacredly respect the life of others is right.