  At Apology 19e–20c Plato represents Socrates as naming four individuals who undertake to teach or educate people (paideuein anthrōpous) in return for fees; they are Gorgias (from Leontinoi in Sicily), Hippias (from Elis, in the north-western Peloponnese, Prodicus (from Ceos, off the southern tip of Attica) and Euenus (from Paros, in the southern Aegean). Of the four only Euenus is expressly said to teach ‘human and political excellence’ (tēs … aretēs … anthrōpinēs te kai politikēs, i.e., success in the running of one’s life and in public affairs), but the context strongly suggests that the other three are seen as offering the same kind of instruction. Euenus is otherwise known chiefly as a poet (though Plato Phaedrus 267a mentions some contributions to rhetorical theory), and his appearance in this context indicates the continuation into the sophistic era of the older tradition of the poet as moral teacher (see above). If Gorgias is included in this context among the teachers of excellence, there is a difficulty in that at Meno 95c Meno, a pupil of Gorgias, says that what he most admires about him is that not only does he never claim to teach excellence, but that he makes fun of those who do. Consistently with that, in the dialogue named after him he begins by claiming that what he has to teach is not any system of values, but a technique of persuasion, which is in itself value-free, but is capable of being employed for whatever purposes, good or bad, are adopted by the person who has mastered it, just as skill in martial arts can be used for good ends or bad (456a–457c). But in fact the distinction is not so clear, since Gorgias is readily induced to agree that a political orator has to know what is right and wrong, and that he (Gorgias) will teach his pupil those things if he happens not to know them already (460a–c). Perhaps it is assumed that normally the pupil will know in advance what is right and wrong, so Gorgias will not have to teach him that, and can concentrate on the essential skill of persuasion. But the point of learning to persuade will be to gain power over others, and thereby to achieve personal and political success. So Gorgias will rightly be counted among the teachers of excellence; what is distinctive about his teaching is the prominence of persuasion in the achievement of excellence. But persuasion, though central, was not everything. At the opening of the dialogue (447d–448a) Gorgias claims to be able to answer any question anyone puts to him, and says that for many years no-one has asked him anything new, which seems to mean ‘asked me any question to which I didn’t already know the answer’ (see also Meno 70b). Making this claim seems to commit him to the kind of encyclopedic knowledge which we find Hippias displaying (see below). His extant writings include display speeches, purportedly in defence of Helen and Palamedes against charges of treachery (DK 82B11 and 11a); they seem to be intended partly as examples of stylistic brilliance for its own sake and partly as demonstration of skill in adversarial argument, ‘making the weaker argument the stronger’ (see above). In addition, we have a philosophical essay ‘On Non-Being or On Nature’ (DK 82B3), purporting to be a rebuttal of Parmenides, in which he maintains that nothing exists, that if anything did exist it could not be known and that if anything could be known it could not be communicated. Scholarly opinion has been and remains divided as to whether this was intended as a parody of Eleatic writing or as a serious piece of philosophy. What can definitely be said is that it shows some knowledge of Parmenides, that it at least raises serious philosophical questions, such as the relation of thought to reality and the possibility of referring to things which do not exist, that no question which it raises is developed to any significant extent and that most of its arguments are extremely feeble. It reads like a piece written by a clever man with no real interest in philosophy, but it is doubtful whether we shall ever know why he wrote it.