Moral codes differ because they adjust themselves to historical and environmental conditions. If we divide economic history into three stages—hunting, agriculture, industry—we may expect that the moral code of one stage will be changed in the next. In the hunting stage a man had to be ready to chase and fight and kill. When he had caught his prey he ate to the cubic capacity of his stomach, being uncertain when he might eat again; insecurity is the mother of greed, as cruelty is the memory—if only in the blood—of a time when the test of survival (as now between states) was the ability to kill.
