Near the beginning of Sophistry and Political Philosophy, the author cites Friedrich Nietzsche’s observation that our “contemporary way of thinking” is “Protagorean.” If so, then understanding sophistry in general and its inventor, Protagoras, in particular is a key to understanding ourselves. The deepest account of Protagoras’ thought, this book argues, comes to us via Plato. Careful consideration of Plato’s treatment of Protagoras becomes a starting-point for self-understanding.

Robert Bartlett is an ideal guide for such an exploration. The Behrakis Professor of Hellenic Political Studies at Boston College, he has published widely-used translations of the Protagoras and Aristotle’s Nicomachean Ethics, as well as a book on the project of enlightenment, both modern and ancient, called The Idea of Enlightenment: A Post-Mortem Study (2001). As befits a careful translator and thinker, his account of Plato’s account combines exactitude and lucidity.

Plato does not make this work easy. The path to understanding the Platonic Protagoras is complicated by Plato’s decision to render him in not one but two dialogues, the Protagoras and the Theaetetus. Further, Plato makes these dialogues almost bookends of his dramatic presentation of Socrates’ life. The Protagoras takes place early, shortly after Socrates’ famous “turn” to speeches about human things, above all, virtue. The Theaetetus takes place on the morning of the very day that Socrates receives his indictment for corrupting the young and not believing in the city’s gods, an indictment that leads shortly to his trial and execution. At first glance, the Protagoras seems to present Protagoras’ political teaching while the Theaetetus offers his theory. The reader’s task is to combine them into a single account.

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In the dialogue that bears his name, Protagoras appears amid a select group of admirers, students, and even a few competitors. In such a setting, and with a potential customer at his side, it is not difficult for Socrates to get Protagoras to state what it is he offers. Protagoras boldly asserts that he teaches his listeners “good counsel” on managing their own affairs well and on being most powerful in their cities. As Bartlett notes, Protagoras leaves unspecified whether that power serves the city’s good or the students’ own advantage. In addition, Protagoras boasts that he is the first to call himself a “sophist” and that as a teacher he has “filled Greece” with his name. At the same time, he hints that there may be some good reasons for prior sophists’ self-concealment: he reveals that at times he too conceals his thought with politic lies.

Prompted in part by Socrates’ questioning, Protagoras also claims to be a teacher of virtue. As Bartlett notes, Protagoras here improves his own appearance with a view towards his audience, namely, several politically ambitious young Athenian gentlemen. Still, this improvement is not only exoteric. Sophistry extends its “clever speaking” to the politically most relevant matters: the just, the good, and the beautiful or noble. The Protagoras thus supports Socrates’ striking comment in the Republic that the cities are themselves the “greatest sophists.” Every healthy political community—ancient and modern—that is, every community that has not lost all faith in itself, nurtures its young in a certain way of life it calls “good.” Though competing with the city, the sophist is, so to speak, in the same business.

This initial appearance of the sophist is meaningful even though the Protagoras demonstrates, as I will explain below, that the sophist is so far from being a teacher of excellence that he does not know what virtue is and even denies, ultimately, that it can be taught. Unlike the city, which holds its truths to be divinely inspired or at least self-evident, Protagoras teaches that “political virtue” (moderation, justice, and piety) is merely conventional, an artful product of the “real men” who collect individual human beings into a common herd. Citizens do not so much learn this political virtue as become habituated in it through beatings, real and metaphorical.

But under Socrates’ questioning, Protagoras goes further, repudiating convention not just for the sake of liberation or even for the sake of power (which might come to those “real men” who make manners and morals) but rather to reveal nature, a nature that he implies provides guidance for life, in the direction of the pursuit of individual pleasure. Protagoras’ conventionalism leads to hedonism. The difference between Protagoras’ conventionalism and his hedonism might explain the difference between his two sets of students: those who are politically ambitious and those (of which we see only one example in this dialogue, Antimoerus) who wish to become sophists themselves. At any rate, Protagoras’ identification of “the good” with pleasure is a point that Socrates does not simply reject. To the contrary, in the latter part of the Protagoras Socrates outlines—for Protagoras, their young onlookers, and the companion and others to whom he relates this dialogue—a science of measuring pleasure that improves upon Protagoras’ hedonism. Of course, as Bartlett notes, this elaboration does not necessarily mean that Socrates is a hedonist.

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Thus far, the Platonic presentation of sophistry shows the sophist as an apparent teacher of virtue, one who liberates his students from their attachment to convention in the direction of the pursuit of pleasure. This liberation, while publicly disreputable, carries with it its own pleasure. As many have noted, the sophist’s conventionalism, which denies humanity a political nature and denigrates virtue, is an important link between sophistry and modern thought. Sophistry’s hedonism has also played a large role in modern thinking. These are but two ways in which our contemporary way of thinking is “Protagorean.”

But this is only the first, not the last, word in Plato’s account of Protagoras. In the Theaetetus, an old Socrates resurrects the long-dead Protagoras. As Bartlett observes, while in the Protagoras the sophist cleans up his teaching for the sake of attracting students, in the Theaetetus Socrates rehabilitates and perhaps improves on Protagoras’ views for the sake of clarifying a question central to his own life: “What is knowledge?” Indeed, is knowledge even possible? Contrary to many contemporary scholars’ view of the dialogue, Bartlett observes that Socrates’ impending trial and execution underscore that this is no mere “epistemological” inquiry.

Bartlett finely traces Socrates’ shifting account of Protagoras’ teaching, an account whose movements appear to imitate the doctrine at its core. Protagoras holds that, behind our perceptions, all is in motion or flux. The perceiver too moves, changing from moment to moment. Not just being but even becoming, as a condition of some “thing” that becomes, falls into doubt. All speech does violence to the truth of the way things are, appearing to fix at rest that which is always moving.

Further, Protagoras’ flux extends to moral matters, the noble and just things. This clear connection between the “theoretical” Theaetetus and the more “political” Protagoras is not surprising. The surprise, Bartlett emphasizes, is that Socrates speculates that the bold Protagoras may have even dared to include “good” itself within the flux. But why, since doing so would have undercut his claim to teach a wisdom that benefits his students and justifies his hefty fees?

Here Bartlett delicately unfolds what he sees as the true core of Protagoras’ thought. Protagoras, the professor of “good counsel,” recognizes that his true competitors are not the other individual sophists. They are, rather, the authorities who claim to direct human life towards the good: above all the prophets, who speak on behalf of the gods, or the supposed gods themselves. From childhood, we are told that these authorities know what is good for us. Protagoras’ radical response is to deny the objectivity of the good. As Bartlett puts it, the sophist may say to someone who claims to speak with or for a god: I cannot know that the god is or is not. “I know only that you cannot know that I am wrong.” Protagoras’ radical relativism makes it impossible to take seriously the demand of obedience that issues from faith.

Bartlett thus allows us to recognize that what today may seem to many people most obvious—that the good is relative or that each of us has, as Justice Anthony Kennedy put it, “the right to define one’s own concept of existence, of meaning, of the universe, and of the mystery of human life” as he or she sees fit—has a radical theoretical consequence. In such a light, sophistry looks almost noble. Even though he recognizes the centrality to human communities of belief in the gods, the sophist bravely rejects the imperative to kneel.

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Sophistry might also, thereby, seem to empower reason. But, Bartlett shows, such a claim would go too far. In truth, Protagoras’ position cuts reason off at the knees. Plato dramatizes this point in the Protagoras by emphasizing Protagoras’ “daring.” Protagoras’ attachment to a kind of “noble courage” makes him unwilling to accept Socrates’ putative definition of courage as wisdom, as knowledge of what is, and is not, truly fearful—a definition that would sap courage of its noble, self-sacrificial character. When the Protagoras of the Theaetetus undercuts the authority of the prophets, by asserting the motion thesis and especially the relativity of the good, he is at his most daring, for he also sacrifices science or knowledge. What resides behind the “true for me” or “good for me” remains shrouded in mystery—a mystery that perhaps accords with Protagoras’ attachment to “noble courage.” As Bartlett shows, this is the ground on which Socrates meets Protagoras’ challenge: not his conventionalism or hedonism or other theoretical arguments but rather Protagoras’ unexamined attachment to a certain type of virtue and the hopes it carries with it—in other words, Protagoras’ morality.

Bartlett reminds us that understanding sophistry in this way draws attention to the surprising moral character of modern thought. It too is daring. Despite asserting, or just assuming, the relativity of the good, modern thought remains attached to claims about justice, as in the ubiquitous discourse on “human rights.” Sophistry also sheds light on the curious place of science in modernity, which more and more has tended to appear as just one “narrative” among others. Such a demotion is not so much the result of an attack on science by sophistry, but is rather an expression of the irrational core of much contemporary thought.

Thus, as much as he respects Protagoras, Socrates makes clear that he does not accept Protagoras’ teaching. To take one dramatic indication of this point: just after the conversation in the Theaetetus he meets Euthyphro, a man who claims to possess inner conviction of god’s will. Just before he is to hear his indictment for impiety, Socrates engages this would-be prophet in a conversation about piety (depicted in Plato’s Euthyphro), a conversation Protagoras could never have taken seriously. Plato suggests that the only path to a true rationalism lies through engaging with, rather than spurning or despising, the beliefs of the faithful. There is a lesson here for us.

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A serious consideration of sophistry thus illuminates not only modern thought but also sophistry’s perennial alternative, philosophy. The Theaetetus indicates that, on the one hand, there are the pre-Socratic philosophers, who share Protagoras’ interest in motion or nature, but who differ from the sophist by being altogether apolitical. On the other hand, there is Socrates, who knows the marketplace and his way to the courthouse, but whose puzzling “teaching”—that virtue is knowledge—the daring sophist finds intolerable. Political philosophy, in the form of Socrates, emerges in a middle ground between pre-Socratic natural science and sophistry. It shares the former’s claim to know nature, while it shares the latter’s attention to “the speeches.” It shares sophistry’s awareness of a problem unseen by the natural philosophers while offering a solution not accepted by the sophists.

If accurate, this provisional description of sophistry may help explain the importance of Protagoras to Socrates. As Bartlett argues, the Protagoras is the third dialogue (after the two Alcibiades) to occur after Socrates’ famous “turn.” Plato nowhere dramatizes this turn itself. Instead, all but one of the dialogues follow the turn, while the exception, the Parmenides, precedes it. (The “young Socrates” of the Parmenides is “pre-Socratic”; he looks down upon the merely apparent world and men’s speeches.) However, Socrates lets slip in the Protagoras that he had spoken, at least once before, with Protagoras, during the sophist’s prior visit to Athens. Could it be that this unseen conversation was decisive in Socrates’ turn from natural science to speeches? If so, sophistry comes to light as crucial to understanding and reclaiming philosophy itself.