Protagoras and Logos: A Study in Greek Philosophy and Rhetoric

12 PROTAGORAS "VERSUS" PLATO AND ARISTOTLE

12 PROTAGORAS "VERSUS" PLATO AND ARISTOTLE The long-standing tradition is that the paucity of extant fragments by Protagoras is due in large measure to the treatment his teachings received by Plato and Aristotle. There is both truth and falsity in this tradition. It is true that the neglect of the Sophists' writings by members of Aristotle's Lyceum contributed to the loss of those writings. It is also true that both Plato and Aristotle attacked Protagoras' doctrines in some of their most important works. I believe, however, that the relationship between the thinking of Plato and Aristotle and that of Protagoras is more subtle than is usually imagined. In this chapter I want to reconsider the relationship between Protagoras and the two fourth-century philosophers. THE REFUTATION OF PROTAGORAS Plato's and Aristotle's two most significant objections to Protagoras' doctrines were that his human-measure statement refuted itself and that it violated the law of noncontradiction. These objections represent enduring arguments against certain versions of relativism, as is indicated by their reemergence in recent literature concerning rhetoric as a way of knowing.l Given the persistence of the arguments, it is important 190 Protagoras "Versus" Plato and Aristotle to understand each objection and to consider what Protagoras might have offered as a defense. Plato's initial interpretation in the Theaetetus is generally accepted as a reasonable paraphrase of Protagoras' human-measure statement: "Everything is, for me, the way it appears to me; and is, for you, the way it appears to you."2 Plato suggested that Protagoras asserted that if a person (or persons) were to judge that A is B, then in fact A is B. Likewise if a person (or persons) were to judge that A is not-B, then in fact A is not-B. The objection runs as follows: If a person is a judge of what-is and what-is-not, and if many people believe that Protagoras' humanmeasure statement is not true, then by Protagoras' own logic his statement is proved false. As Barnes puts it, the human-measure statement "suffers an about-turn: it marches to its own ruin."3 Plato argued in the Theaetetus: And what about Protagoras himself? Isn't it necessarily the case that, if he didn't himself think a man is the measure, and if the masses don't either, as in fact they don't, then that Truth which he wrote wasn't the truth for anyone? Whereas if he did think so himself, but the masses don't share his view, then, in the first place, it's more the case that it isn't the truth than it is: more in the proportion by which those to whom it doesn't seem to be outnumber those to whom it does.4 Thus, Plato concluded that "since it's disputed by everyone, it would seem that Protagoras' Truth isn't true for anyone."5 The self-refutation argument was a popular objection to Protagoras' positions, appearing in the works of Democritus and Sextus Empiricus, among others.6 In Sextus the argument appears as: "If every appearance is true, then the belief that not every appearance is true-once this belief takes the form of an appearance-will also be true, and so the belief that every appearance is true will become false. "7 In recent times Jack Orr has charged that rhetorical theorist Barry Brummett's intersubjectivist criterion of truth-as-agreement is subject to a similar inconsistency: "The definition of truth as agreement validates views of truth that intersubjectivism itself denies."8 And a considerable number of modern philosophers are still debating whether or not Protagorean relativism is "really" self-refuting.9 Though the continued interest in Protagorean relativism is significant, most of the debates are based on contemporary appropriations rather than historical reconstructions , and hence are not examined in depth here.lO The second objection to Protagoras' philosophy is that it violates the 191 Protagoras and Early Greek Philosophy and Rhetoric principle of noncontradiction. The principle can be summarized as "It is a property of being itself that no being can both have and not have a given characteristic at one and the same time."11 If human(ity) is the measure, then Protagoras must allow that "things" can be in two contradictory ways at the same time: good and bad, true and false, etc. Plato and Aristotle added to...