It is unnecessary to quote the opinions of other moral philosophers. It is enough to observe that most of them describe the moral law as a social agreement and make conscience its accredited representative. L. Lévy-Brühl repeats a doctrine current since the days of Pythagoras when he says: "The sense of duty and that of responsibility, horror of crime, love of what is good and reverence for justice--all these, which a conscience sensitive to Morality thinks it derives from itself and from itself alone, have nevertheless a social origin"; and Feuerbach expresses the same view in an entertainingly melodramatic fashion when he calls the voice of conscience "An echo of the cry of revenge uttered by the injured party." This cry of revenge would never wake an echo in us if we did not possess a sounding board which cries of distress and lamentation cause to vibrate. Schopenhauer, digging deeper than his predecessor, clearly recognizes this sounding board, and describes its characteristics when he says that the foundation of ethics is pity, which in its passive form warns us: "_Neminem laede!_ Do harm to no one!" And in its active form gives the order: "_Imo omnes quantum potes juva!_ Assist everyone with all your might!" The assumption, that sympathy with his neighbour must be present in man's consciousness before he is capable of moral action, is one that need not be made by subjective moral philosophers, who hold with Kant and his school that the moral law is an inborn categorical imperative, which proclaims its commands without reference to any extraneous object, or to the world, or mankind. In the same way the theologians have no need of it, for they consider that what is morally good is the Will of God. But he who holds with the moral philosophers of sociological tendencies that Morality is regard for one's fellow men, and the recognition that the claims of the real or supposed interest of the community are superior to those of the comfort of the individual, must admit that sympathy is a necessary preliminary to moral action; i.e. that the individual must have the ability to picture the sufferings of others so vividly that he feels their sorrows as his own, and with all his might and all his will strives to prevent, alleviate and heal them. The lack of this ability, psychic anæsthesia, is a symptom of disease. It renders the person affected incapable of moral action. It is a characteristic of the born criminal, and is the essential symptom of that state of mind which alienists term moral insanity. Even in this condition, if reason and the power of judgment are not affected, great offences against current moral law can be avoided. But this results from the fear of the painful and ruinous results which a collision with public opinion entails, even if the offender is not actually haled into court. It is not due to any inner necessity, nor to the prompting of one's own feelings.