The society of which he is a member, and which makes his existence possible, prescribes to the individual the laws governing his moral conduct. That which a community at any given time approves and demands, rejects or forbids, constitutes the precept whereby its members regulate their conduct, and offers ample security for their conscience.
The concepts Good and Bad originate simultaneously with society; they are the form in which its actual conditions of existence are conveyed to the consciousness of its members. The only immutable thing about them is the fact of their continued existence. Without the coercive discipline of a rule conducive to the common weal and governing the mutual relations between its members, no society could be imagined to exist, unless its members were all similar in nature, reacted in an identical fashion to all impressions and possessed the same feelings and sensations, the same inclinations and the same impulses of volition. In that case no difference could ever arise between one individual and another, or between an individual and the community, which would have to be smoothed over by the moral law emanating from the community and controlling the individual, or be suppressed by the community's order. Every individual could be left to the guidance of his own instincts, for he would know himself always to be in agreement with the community; no consideration for others need hamper or modify his actions; he could behave just as if he were alone in the world. But as individuals differ from one another, feel, think and want different things, collisions in which they hurt, cripple or even kill one another are the inevitable consequence of their opposing movements; and the interference of the moral law is absolutely necessary to polarize these movements and guide them into parallel courses, so that they do not run counter to one another.
But Good and Bad derive not only their existence but their measure and their significance from the views of the community. They are therefore not absolute but variable; they are not an immutable standard amid the ever-changing conditions of humanity, a rule by which the value of the actions and aims of mortals are indisputably determined, but are subject to the laws of evolution in society and therefore in a constant state of flux. At different times and in different places they present the most varied aspects. What is virtue here and now may have been vice formerly and at another spot, and _vice versa_. In the royal family of ancient Egypt marriage between brothers and sisters was the prescribed custom. We call this incest and it fills us with horror. To the sons of Egypt it seemed meritorious and constituted a claim to special veneration. The Babylonians and Canaanites burnt their first-born in Moloch's fiery furnace, and this sacrifice was accounted a highly praiseworthy act of piety and of the fear of God. The Spartans taught their sons, their future warriors, the art of stealing without being caught; and he who did this most cleverly achieved the most flattering recognition. The Cherusci butchered the Roman prisoners taken from the legions of Varus as a sacrifice to their tribal gods, and a noble-minded and brave man like Arminius considered this absolutely honourable and knightly. The Aztecs, who had undeniably attained an advanced degree of civilization, at high festivals used with obsidian knives to cut open the breasts of human sacrifices on the altars of their gods, and tear the heart out of their living bodies. That was an action finding favour in the sight of the gods, and the people watched it with awe and those mystic emotions which religious rites are intended to arouse.