Starting from purely arbitrary assumptions concerning allegedly eternal and absolute values and perennial justice, they arrogate to themselves the office of the supreme judge of earthly affairs. They misconstrue their own arbitrary value judgments derived from intuition as the voice of the Almighty or of the nature of things. There is, however, no such thing as a perennial standard of what is just and what is unjust.
Nature is alien to the idea of right and wrong.
The characteristic feature of natural conditions is that one animal is intent upon killing other animals and that many species cannot preserve their own life except by killing others. The notion of right and wrong is a human device, a utilitarian precept designed to make social cooperation under the division of labor possible. All moral rules and human laws are means for the realization of definite ends. There is no method available for the appreciation of their goodness or badness other than to scrutinize their usefulness for the attainment of the ends chosen and aimed at. From the notion of natural law some people deduce the justice of the institution of private property in the means of production.