Plato, unlike Xenophon, is generally regarded as a philosopher of the highest order of originality and depth. According to some scholars, his philosophical skills made him far better able than Xenophon was to understand Socrates and therefore more valuable a source of information about him. The contrary view is that Plato’s originality and vision as a philosopher led him to use his Socratic discourses not as mere devices for reproducing the conversations he had heard but as vehicles for the advocacy of his own ideas (however much they may have been inspired by Socrates) and that he is therefore far more untrustworthy than Xenophon as a source of information about the historical Socrates. Whichever of these two views is correct, it is undeniable that Plato is not only the deeper philosopher but also the greater literary artist. Some of his dialogues are so natural and lifelike in their depiction of conversational interplay that readers must constantly remind themselves that Plato is shaping his material, as any author must.

Although Socrates is the interlocutor who guides the conversation in most of Plato’s dialogues, there are several in which he plays a minor role (Parmenides, Sophist, Statesman, and Timaeus, all of which are generally agreed to be among Plato’s later works) and one (Laws, also composed late) in which he is entirely absent. Why did Plato assign Socrates a small role in some dialogues (and none in Laws) and a large role in others? A simple answer is that, by this device, Plato intended to signal to his readers that the dialogues in which Socrates is the major interlocutor convey the philosophy of Socrates, whereas those in which he is a minor figure or does not appear at all present Plato’s own ideas.

But there are formidable objections to this hypothesis, and for several reasons most scholars do not regard it as a serious possibility. To begin with, it is unlikely that in so many of his works Plato would have assigned himself so passive and mechanical a role as merely a recording device for the philosophy of Socrates. Furthermore, the portrait of Socrates that results from this hypothesis is not coherent. In some of the dialogues in which he is the principal interlocutor, for example, Socrates insists that he does not have satisfactory answers to the questions he poses—questions such as “What is courage?” (raised in Laches), “What is self-control?” (Charmides), and “What is piety?” (Euthyphro). In other dialogues in which he plays a major role, however, Socrates does offer systematic answers to such questions. In Books II–X of Republic, for example, he proposes an elaborate answer to the question, “What is justice?,” and in doing so he also defends his view of the ideal society, the condition of the human soul, the nature of reality, and the power of art, among many other topics. Were we to hold that all the Platonic dialogues in which Socrates is the main speaker are depictions of the philosophy of Socrates—a philosophy that Plato endorses but to which he has made no contributions of his own—then we would be committed to the absurd view that Socrates both has and lacks answers to these questions.

For these reasons, there is a broad consensus among scholars that we should not look to works such as Republic, Phaedo, Phaedrus, and Philebus for a historically accurate account of the thought of Socrates—even though they contain a speaker called Socrates who argues for certain philosophical positions and opposes others. At the same time, we can explain why Plato uses the literary character of Socrates in many of his writings to present ideas that go well beyond anything that the historical Socrates said or believed. In these works, Plato is developing ideas that were inspired by his encounter with Socrates, using methods of inquiry borrowed from Socrates, and showing how much can be accomplished with these Socratic starting points. That is why he assigns Socrates the role of principal interlocutor, despite the fact that he did not intend these works to be mere re-creations of Socrates’ conversations.

Accordingly, the dialogues of Plato that adhere most closely to what he heard from Socrates are those in which the interlocutor called Socrates searches, without apparent success, for answers to questions about the nature of the ethical virtues and other practical topics—works such as Laches, Euthyphro, and Charmides. This does not mean that in these dialogues Plato is not shaping his material or that he is merely writing down, word-for-word, conversations he heard. We cannot know, and it is implausible to suppose, that in these dialogues of unsuccessful search there is a pure rendering of what the historical Socrates said, with no admixture of Platonic interpretation or supplement. All we can reasonably suppose is that here, if anywhere, Plato is re-creating the give-and-take of Socratic conversation, conveying a sense of the methods Socrates used and the assumptions that guided him when he challenged others to defend their ethical ideas and their way of life.

The portrait of Socrates in these dialogues is fully consonant with the one in Plato’s Apology, and it serves as a valuable supplement to that work. For in the Apology, Socrates insists that he does not inquire into natural phenomena (“things in the sky and below the earth”), as Aristophanes alleges. On the contrary, he says, he devotes his life to one question only: how he and others can become good human beings, or as good as possible. The questions he asks others, and discovers that they cannot answer, are posed in the hope that he might acquire greater wisdom about just this subject. This is the Socrates we find in Laches, Euthyphro, and Charmides—but not in Phaedo, Phaedrus, Philebus, or Republic. (Or, rather, it is not the Socrates of Books II–X of Republic; the portrait of Socrates in Book I is similar in many ways to that in Apology, Laches, Euthyphro, and Charmides.) We can therefore say this much about the historical Socrates as he is portrayed in Plato’s Apology and in some of Plato’s dialogues: he has a methodology, a pattern of inquiry, and an orientation toward ethical questions. He can see how misguided his interlocutors are because he is extremely adept at discovering contradictions in their beliefs.

“Socratic method” has now come into general usage as a name for any educational strategy that involves cross-examination of students by their teacher. However, the method used by Socrates in the conversations re-created by Plato follows a more specific pattern: Socrates describes himself not as a teacher but as an ignorant inquirer, and the series of questions he asks are designed to show that the principal question he raises (for example, “What is piety?”) is one to which his interlocutor has no adequate answer. Typically, the interlocutor is led, by a series of supplementary questions, to see that he must withdraw the answer he at first gave to Socrates’ principal question, because that answer falls afoul of the other answers he has given. The method employed by Socrates, in other words, is a strategy for showing that the interlocutor’s several answers do not fit together as a group, thus revealing to the interlocutor his own poor grasp of the concepts under discussion. (Euthyphro, for example, in the dialogue named after him, having been asked what piety is, replies that it is whatever is “dear to the gods.” Socrates continues to probe, and the ensuing give-and-take can be summarized as follows: Socrates: Are piety and impiety opposites? Euthyphro: Yes. Socrates: Are the gods in disagreement with each other about what is good, what is just, and so on? Euthyphro: Yes. Socrates: So the very same actions are loved by some gods and hated by others? Euthyphro: Yes. Socrates: So those same actions are both pious and impious? Euthyphro: Yes.) The interlocutor, having been refuted by means of premises he himself has agreed to, is free to propose a new answer to Socrates’ principal question; or another conversational partner, who has been listening to the preceding dialogue, is allowed to take his place. But although the new answers proposed to Socrates’ principal question avoid the errors revealed in the preceding cross-examination, fresh difficulties are uncovered, and in the end the “ignorance” of Socrates is revealed as a kind of wisdom, whereas the interlocutors are implicitly criticized for failing to recognize their ignorance.

It would be a mistake, however, to suppose that, because Socrates professes ignorance about certain questions, he suspends judgment about all matters whatsoever. On the contrary, he has some ethical convictions about which he is completely confident. As he tells his judges in his defense speech: human wisdom begins with the recognition of one’s own ignorance; the unexamined life is not worth living; ethical virtue is the only thing that matters; and a good human being cannot be harmed (because whatever misfortune he may suffer, including poverty, physical injury, and even death, his virtue will remain intact). But Socrates is painfully aware that his insights into these matters leave many of the most important ethical questions unanswered. It is left to his student Plato, using the Socratic method as a starting point and ranging over subjects that Socrates neglected, to offer positive answers to these questions.

Aristotle

Another important source of information about the historical Socrates—Aristotle—provides further evidence for this way of distinguishing between the philosophies of Socrates and Plato. In 367, some 30 years after the death of Socrates, Aristotle (who was then 17 years old) moved to Athens in order to study at Plato’s school, called the Academy. It is difficult to believe that, during his 20 years as a member of that society, Aristotle had no conversations about Socrates with Plato and others who had been personally acquainted with him. There is good reason, then, to suppose that the historical information offered about Socrates in Aristotle’s philosophical writings are based on those conversations. What Aristotle tells his readers is that Socrates asked questions but gave no replies, because he lacked knowledge; that he sought definitions of the virtues; and that he was occupied with ethical matters and not with questions about the natural world. This is the portrait of Socrates that Plato’s writings, judiciously used, give us. The fact that it is confirmed by Aristotle is all the more reason to accept it.