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.