Journal of the History of Philosophy

Notes and Discussions THE DIGRESSION IN THE 'THEAETETUS' The relation between the "digression" in Theaetetus 172-177 and the arguments which surround it in the text is not commonly investigated very closely. Though Ryle's characterization of the passage1 as "long and philosophically quite pointless" is perhaps extreme, it seems to reflect a generally held view that this comparison of philosopher and non-philosopher, however interesting, is one for which the context provides no philosophical excuse. Even Cornford, though he attempts to explain the passage in relation to the sentences introducing it, finds it necessary to interpret it as a reply, not to Protagoras and his associates, who are the subject of the surrounding sections, but to certain extreme "conventionalists," of whom Cornford takes Thrasymachus as the type, and whose thesis, to Plato, "is the position of the arch-enemy.''2 That it may indeed be; but the relevance of an assault on this particular Scarlet Woman would in the context be slight, and it would have no tendency whatever to undermine the thesis concerning the nature of knowledge at which the first part of the Theaetetus is directed. In this short note I want to suggest an alternative interpretation which would make the links between the "digression" and its context more direct. Not that I want to deny that it is a digression Plato himself describes it as such (n~eeQya, 177b8)---but it is, I believe, a digression only in the sense that it develops ideas for their own sake beyond the needs of the general argument in which it is imbedded, and not in the sense that it has no direct relevance to the general argtunent at all. Let us first remind ourselves briefly of the context in which the digression is set. After the first statement of the theory that knowledge is perception, its association with the Protagorean homo mensura, and the lengthy elaboration and explication of this latter doctrine,3 Plato launches into a sequence of what might be called "popular" refutations of the theory, that is, a set of simple counter-arguments having undoubted initial plansibility , but not of a kind which Plato took to be philosophically conclusive. Their function in the dialogue, it appears, is in fact to give a cue for the further sophistication of the doctrine under discussion, and not to destroy it out of hand. The first group of them (158-165) is followed by a major restatement of the Protagorean view (166-168), of which the most important part, for our purposes, runs from 166c to 167d. Here we are told, in particular, that for Protagoras the thesis "each man is the measure of what is and what is not" (rd~Qov y&o ~• ~t~v e~vaL~6~ re ~wr xM rdl, 166d2) is fully compatible with the claim that one man is wiser than another. The wise man is the doctor of the mind, the man who has the technique to alter another so that in place of "unhealthy" judgements he comes to have "healthy" ones: neither set of judgments is "truer" than the other, but the one is better for the man in the sense, apparently, that it contains views which lead to better prospects and greater experience of success. In a G. Ryle, Plato's Progress (Cambridge: Cambridge University Press, 1966),p. 158. 2 F. M. Cornford, Plato's Theory o] Knowledge (London: Routledge, 1935),pp. 81-83. I am not concerned in the present article with the question of the accuracy or fairness of Plato's portrait of Protagoras here. For the purposes of this paper "Protagoras" will mean "Protagoras as here presented and interpreted by Plato," though there can be little doubt that the doctrines attributed to him in this dialogue are not altogether those of the sophist himself. But thisis a separate controversy. [457] 458 HISTORY OF PHILOSOPHY any given state, what seems right is right for as long as it is so regarded; which seems to make it reasonable to assume that the "cure" of individuals will largely take the form of instruction designed to bring them into line with the mores of their community.4 But states too may be unhealthy...