In conversation with Socrates, Meno asks whether virtue can be taught. Socrates suggests that the two of them are to determine whether virtue can be taught, they must first define clearly what virtue is.

Meno first suggests that different kinds of virtue exist for different kinds of people. Socrates replies that Meno’s definition is like a swarm of bees: each kind of virtue, like each bee, is different, but Socrates is interested in that quality they all share. Meno next suggests that virtue is being able to rule over people, but Socrates dismisses this suggestion on two grounds: first, it is not virtuous for slaves or children to rule over people, and second, ruling is virtuous only if it is done justly. This response prompts Meno to define virtue as justice. But he then concedes to Socrates that justice is a form of virtue but not virtue itself.

Struggling with Socrates’ demands for a definition, Meno asks him to give an example of definitions of shape and color. Socrates first gives a straightforward definition of shape (“the limit of a solid”) and then an elaborate definition of color in the style of the sophists, which shows up their empty pretentiousness.

Meno attempts to define virtue again, suggesting that it involves desiring good things and having the power to secure them, but only if one does so justly. However, this definition again encounters the problem of using “justice” in a definition of virtue: we cannot define something by using an instance of what it is we are defining.

Meno compares Socrates to a torpedo fish, which numbs anything it touches. Socrates has struck Meno dumb, and Meno no longer knows what to say. If they don’t even know what virtue is, he asks, how are they to know what to look for?

Socrates responds that learning is not a matter of discovering something new but rather of recollecting something the soul knew before birth but has since forgotten. To show what he means, he calls over one of Meno’s slave boys, draws a square with sides of two feet, and asks the boy to calculate how long the side of a square would be if it had twice the area of the one he just drew. The boy suggests four feet and then three feet, and Socrates proves him wrong both times. Socrates then helps the boy recognize that a square of twice the area would have sides with a length equal to the diagonal of the present square—but Socrates leads the boy to this point without actually explaining anything, instead forcing the boy to think the problem through himself. Since the boy reached this conclusion (more or less) on his own without any direct teaching, he must have been recollecting something he already knew.

Meno wants to return to the original question—whether virtue can be taught—and Socrates proposes two hypotheses to lead them on their way. First, if virtue is a kind of knowledge, then it can be taught, and second, if there is anything good that is not knowledge, then it is possible that virtue is not a kind of knowledge. Adding that nothing is good unless it is accompanied by wisdom, Socrates concludes that virtue is wisdom, in whole or in part, so it can’t be something we’re born with.

Meno is ready to conclude that virtue can be taught, but Socrates is hesitant. If virtue can be taught, where are the teachers? When questioning Anytus, a prominent Athenian, Socrates proposes that the sophists teach virtue. Anytus is outraged because he considers the sophists to be a source of corruption. He suggests instead that any Athenian gentleman is a teacher of virtue, but Socrates points out that many Athenian gentlemen have had dissolute sons to whom they clearly failed to teach virtue. Not even the great poet Theognis seems to have known whether virtue could be taught, leading Socrates to conclude that maybe it isn’t a kind of knowledge even though it is a kind of wisdom.

Socrates suggests that virtue is perhaps not a result of knowledge but of true belief. Knowledge is a matter of being able to give an account of what we know, as the slave boy with the mathematical proof, while we can hold true beliefs without being able to justify them.

The final conclusion, then, is that virtue neither is something innate nor can be taught. Socrates muses that perhaps it is simply a “gift from the gods” that we receive without understanding.

Many scholars view the Meno as a transitional work between Plato’s early and middle periods because it combines features typical of the early Socratic dialogues with the beginnings of more refined theories. We have one of the more worked-out examples of the Socratic elenchus, where Socrates uses questioning to draw out an admission of ignorance from his the person he is arguing with, and the dialogue ends in aporia, the state of inconclusive perplexity. These features are typical of other early works. On the other hand, we find what may be a prototypical Theory of Forms in Socrates’ insistence that we find what all instances of virtue share. The theory that knowledge is recollection draws on a desire to see knowledge as grounded not in the vagaries of everyday life but in some form that would cement true knowledge as unchanging and eternal. Such positive steps are absent in Plato’s other early works and are typical of so-called middle period dialogues such as the Phaedo and the Republic.

Plato takes a few significant steps beyond the typical reach of a Socratic dialogue when he describes Socrates questioning the slave boy, since this type of dialogue usually includes only a pattern of arguments and refutations. The questioning begins in a manner typical of Socrates’ elenchus. He asks the slave boy if he knows the length of the side of a square with twice the area of the square he has drawn and then uses questions and counterarguments to bring the boy to a position of acknowledging that he doesn’t know. In compressed form, this is how a typical early dialogue unfolds. By means of questioning, Socrates takes someone who is confident in his knowledge and brings him to a place of recognizing his own ignorance. However, once Socrates has brought the slave boy to this state of perplexity, he leads him back out. The slave boy emerges from their exchange with a positive knowledge of mathematics, which he did not have coming in. Furthermore, Socrates claims that the slave boy’s knowledge is a consequence of recollecting something he always knew. In other words, their dialogue-within-a-dialogue does not end only with a positive conclusion. It also ends with a positive theory from Socrates to explain this positive conclusion.

When Socrates claims that knowledge is recollection, he is not only explaining what form our knowledge takes but also redefining what qualifies as knowledge at all. Clearly, the definition does not apply to everything we normally consider knowledge. When we find out in the newspaper what happened the previous day, we are not discovering things we’ve always known but forgotten. We get a hint about what counts as knowledge in the distinction Socrates draws toward the end of the dialogue between knowledge and true belief. This distinction, which plays an important role in the Republic, implies that we can be confident in knowing something only if we can give an account of, or justify, our knowledge. The slave boy may have guessed the answer to the mathematical problem at the outset, but he can be sure he knows the answer only because he went through the problem step by step, ensuring that he made no mistakes. This sort of rigorous justification applies only to subjects that consist of unchanging, abstract entities that are not subject to the errors and vagaries of everyday experience, such as mathematics. What we learn from the newspaper can never amount to more than true belief.

The argument that knowledge is recollection is bold and challenging, but it contains a number of problems. Foremost is the controversial question of whether the slave boy does in fact arrive at his own conclusions. Strictly speaking, Socrates only prompts the slave boy with questions, but he often makes statements couched in the form of questions, in which he arguably tells the boy the right answer rather than allowing him to figure it out for himself. Even if we do accept that the boy reaches the right answer on his own, it takes another leap to trust that he does so only by recollecting knowledge that he already possessed—let alone knowledge that he possessed before he was even born, as Socrates actually asserts. We could object first that the boy is not activating latent knowledge so much as latent ability. By claiming that the boy’s knowledge must be recollection, Socrates assumes that he is passively absorbing a set of facts rather than actively learning how to think mathematically. Second, we could object that the doctrine of knowledge as recollection does not explain how we first come to know things. Even if we believe that all the knowledge we possess came to us before we were born, such as in a previous life, we would still face the question of how we gained that knowledge in the first place.