Over the past decades attempts to explain human social behavior in biological terms made by ethologists and sociobiologists have attracted political theorists who have gone back to Darwinism. This essay presents Darwin's thought as the cultural context in which the themes of ethology and sociobiology could unfold. The Darwinian paradigm is based on a paradox: it creates a discourse about nature that revolves around the indeterminate character of nature. Indeed this indeterminate character is the necessary prerequisite of evolution. There are no scientific data that could be used by political theory to show that politics is rooted in nature. In the context of Darwinism this last statement is meaningless. But it is useful to look inside Darwinism for its basic character: it is a non-teleogical body of thought basically exposed to teleology.