Protean Socrates: Mythical Figures in the Euthydemus

At the midpoint of the Euthydemus Socrates tries to calm Ctesippus who is enraged by the twin sophists’ arguments about truth and contradiction:

Ctesippus, I say the very same things to you as I said just now to Cleinias,¹ that you don’t recognise the amazing nature of our visitors’ wisdom. But they are not prepared to give us a serious demonstration; instead they imitate Proteus the Egyptian sophist, and cast spells on us.² So let us imitate Menelaus, and not let these chaps go until they manifest to us their serious side.³ For I think that something quite beautiful in them will appear once they start to be serious. So let us beg and advise and pray them to make themselves manifest. Indeed, I think I should begin by giving a pointer to what sort of persons they will, I pray, clearly turn out to be. (Plato, Euthydemus 288b-c)

You might be immediately sceptical of my title. This image of sophists – as slippery shape-shifters – is exactly what we should expect of Plato⁴; surely it is not Socrates, but the sophists, who are Protean in this tale? And surely there is little more to be got from the mythical image than a point which is already being made in the arguments: that these characters really can’t be tied down to a single definitive thesis, can’t be persuaded to stay the same even for a moment, are quite disqualified from entering upon serious⁵ dialectical exchange?