  The evidence of the Theaetetus on Protagorean relativism is therefore ambiguous, since in that dialogue he is represented as maintaining a) universal subjectivism, b) social relativism in morality and c) objective realism on questions of advantage. The evidence of Aristotle and Democritus (transmitted by Sextus) indicates that he did in fact maintain a), but leaves it open whether the attribution to him of b) and c) is historically accurate, thereby indicating inconsistency on his part, or is due to misinterpretation, deliberate or inadvertent, on the part of Plato. It should also be recognized that in the Theaetetus Socrates only attributes b) and c) to Protagoras in his overarching effort, on Theaetetus’ behalf, to explicate and defend as plausibly as possible the ‘Man the measure’ doctrine before refuting it. The portrayal in the Protagoras shows little trace of relativism, either individual or social; instead he maintains that the essential social virtues are justice and self-restraint, and that without universal inculcation of those virtues the survival of society is impossible. These claims are presented as universal truths; there is not the slightest suggestion that in making them Protagoras is merely expressing a preference for these virtues which happens to prevail, e.g., in Athens, but which might be absent from the mores of some other city. It is clearly implied by his exposition that no such city could exist. On the assumption, adopted above, that the presentation of Protagoras’ social teaching in the dialogue is in essentials intended to be historically accurate, we must conclude that Protagoras recognised certain objective truths, not merely on questions of advantage, but in some fundamentals of morality, and consequently that his basic position was inconsistent.