 We here get a better idea of Protagoras’ teaching, which centres on the concept of logos, understood both as the ability to reason and the ability to express oneself (i.e., as both thought and language). “Correctness”, in other words, is to be understood on two levels, a conceptual and a linguistic one: correct reasoning, which expresses the best possible solution, must find a counterpart in formal correctness, which makes one’s speech persuasive and hence allows one to gain the upper hand in each particular situation (Classen 1976: 222–225). The best speech, therefore, is not the speech that is true but the speech that is correct, the speech best suited to the situation at hand and most capable of outdoing others from a formal and logical perspective: an irrefutable logos (Brancacci 2002: 183–190).