Origin of Justice.—Justice (reasonableness) has its origin among approximate equals in power, as Thucydides (in the dreadful conferences of the Athenian and Melian envoys) has rightly conceived. Thus, where there exists no demonstrable supremacy and a struggle leads but to mutual, useless damage, the reflection arises that an understanding would best be arrived at and some compromise entered into. The reciprocal nature is hence the first nature of justice. Each party makes the other content inasmuch as each receives what it prizes more highly than the other. Each surrenders to the other what the other wants and receives in return its own desire. Justice is therefore reprisal and exchange upon the basis of an approximate equality of power. Thus revenge pertains originally to the domain of justice as it is a sort of reciprocity. Equally so, gratitude.—Justice reverts naturally to the standpoint of self preservation, therefore to the egoism of this consideration: "why should I injure myself to no purpose and perhaps never attain my end?"—So much for the origin of justice. Only because men, through mental habits, have forgotten the original motive of so called just and rational acts, and also because for thousands of years children have been brought to admire and imitate such acts, have they gradually assumed the appearance of being unegotistical. Upon this appearance is founded the high estimate of them, which, moreover, like all estimates, is continually developing, for whatever is highly esteemed is striven for, imitated, made the object of self sacrifice, while the merit of the pain and emulation thus expended is, by each individual, ascribed to the thing esteemed.—How slightly moral would the world appear without forgetfulness! A poet could say that God had posted forgetfulness as a sentinel at the portal of the temple of human merit!