Although the physis - nomos antithesis was common in the teachings of most Sophists, their views of physis with regard to human nature could differ widely. To some Sophists, the realization that all men have much the same human nature required the abolishment of all artificial distinctions among men, such as Hellene and Barbarian, master and slave. Other Sophists saw human nature as an aggregate of man's animalistic inclinations to aggression and domination by physical strength. The Sophists who advocated this argument saw men in the image of animals in the wild and often recommended the animal world as a model for the human. According to this view, any attempt to constrain the natural human tendency of aggression is not only wrong, but useless.
Nature overrides any artificial constraints set up by man.
Just as in the animal world, the strong will always be victorious over and dominate the weak. Not all Sophists, however, subscribed to this theory. Protagoras believed that men, left to their own natural savage instincts, would destroy each other. In his view nomos , although only an artificial creation of man, enables men to survive and makes possible civilized communal life. In addition to the arguments of advantage and the right of the stronger, a third line of argumentation popularized by the Sophists was that of probability.