It is peculiarly arbitrary, too, to think that a savage, if he had a conscience, could obey it to the same extent, that is, be just as virtuous, as a Socrates or an Aristides. This would contradict all the observations and experience from which I have derived the doctrine that conscience works by means of inhibition, and that Morality and Virtue from the biological point of view are inhibition. For inhibition is developed by practice and use. Except in cases of morbid disturbance it develops simultaneously with the understanding which manipulates it and demands efficiency from it. There can be no two opinions about the fact that the understanding and the faculty of inhibition in living beings have developed progressively. There is no need to adduce any proof that the frog is intellectually superior to the zoospore, and man to the frog, and that as we ascend the scale of organisms we find their reactions to stimuli are increasingly subject to individual modification, and that there is a gradual transition from the original, purely mechanical tropism to differentiated reflex action, which, however, is still beyond the control of the will, and finally to resistances which suppress every externally visible reply on the part of the organism to the impression it has received. In the course of this development the faculty of inhibition grows stronger and more efficient and obeys the behests of the understanding more and more swiftly, surely and reliably; it can reach a pitch of invincibility against which all the revolts of instinct, all the storms of passion, are powerless.