Thanks. The formulation of "social Darwinism" is relatively recent, of course. But the implicit naturalistic fallacy is found also in ancient justifications of social and political traditions. Patriarchy, sexism, slavery, war, social castes or domination hierarchies--those were supposed to be the facts of how the natural world operates, and therefore the facts were supposed to be good. The reliability of what were implicitly natural norms was supposed to justify them or prove that they were blessed by the gods.