The discussion begins with the question of whether virtue, or goodness, can be taught, or whether it is the result of practice or human nature. Socrates avows that he and his fellow Athenians do not even know what virtue is. So, they do not know what qualities virtue has. Moreover, he asserts that he has never met anyone who did know what virtue is, including the sophist Gorgias.

Meno responds with definitions of virtue for men, women, children, the elderly, and slaves. "There is virtue for every action and every age, for every task of ours and every one of us" (71e). For example, the virtue of a man is "being able to manage public affairs and in so doing to benefit his friends and harm his enemies and to be careful that no harm comes to himself" (71e). Socrates asks for a single form that makes all virtues virtues. Analogously, there is only one thing that makes bees bees. Other analogies are made with health and strength: they are the same for all people.

Meno thinks that somehow virtue is different from these. Socrates leads him to admit that the virtues of men and women have to do with management (of public vs. household affairs), and that these are a function of moderation and justice. Meno suggests that the common virtue is to be able to rule over people, but Socrates counters that this is not a virtue for a child or a slave. He adds that the rule should be just in order for it to be a virtue. Meno allows that justice is virtue.

This sounds as if it is the single thing, but it may mean that justice is a virtue. Meno mentions courage, moderation, wisdom and munificence, along with "very many others." This leads back to the original problem. Socrates puts the problem differently, this time in terms of shape, where roundness is not shape but a shape. The same holds for colors. So what is it by virtue of which the word "shape" applies to round and straight things? To give an answer to this would be "practice" for an answer for virtue.

Socrates consents to discuss what shape is. He suggest that it is the only thing that always follows color. Meno objects that then someone who did not know what color is would not know what shape is. So Socrates defines shape as the limit of a solid, allowing that there could be some dispute (as from the sophist Prodicus) about what a limit is. (Socrates takes this in a way that is "nothing elaborate.") Meno now asks about color, which Socrates defines as "an effluvium from shapes which fits the sight and is perceived" (76d), drawing from Empedocles. He calls this answer "theatrical."

Now Meno gives an answer about what virtue is: "to desire beautiful things and have the power to acquire them" (77b). Socrates goes to work on the answer. He says that someone desiring beautiful things desires good things, thus shifting the focus. Then he asks whether anyone can desire bad things. Meno thinks that they can, even knowing that the bad things are bad. Bad things are what harm those who possess them, and so they would not be desired if known to be bad, because the person desiring them would know that they would be made miserable and unhappy. Nobody wants that. So people only desire bad things when they believe them to be good. This negates the first part of Meno's definition, since now desiring the beautiful is common to everyone, the vicious and the virtuous. What is left is that the virtuous man is better at getting beautiful things.

So what are these things? Along with health and wealth, Meno mentions honors and offices in the city. But of course, gold and silver can be acquired unjustly, in which case it would be wickedness. "It seems then that the acquisition must be accompanied by justice or moderation or piety or some other part of virtue" (78d). Failing to procure things unjustly is virtuous, so it looks like justice is virtue and injustice is wickedness. This is a problem, though, because justice is only part of virtue, by Meno's admission.

Meno now compares Socrates with the torpedo fish that makes everything that touches it feel numb. Meno has made many speeches about virtue but now cannot say what it is. Had Socrates gone out of Athens, he would have been driven away from the other city as a sorcerer. Socrates responds that if he is like a torpedo fish, then he is himself numb. His ignorance about what virtue is has spread to Meno.

The "Meno paradox" is now put forward. Socrates encourages Meno to keep looking for knowledge, but how can someone look for something without knowing what it is? "If you should meet with it, how will you know that this is the thing that you do not know?" (80d). Socrates rejects the argument. He cites myths of rebirth, so that one does not learn because one has already seen it all. Once one has recalled, one can learn many things. This makes one energetic, while the debater's argument makes one lethargic. When Meno asks Socrates to teach him about recollection, Socrates mercilessly scolds him on the grounds that by his theory, Meno would have to recall about recollection!

Meno's slave is called forth for illustration. It is established that he knows what a square is and that it has various properties. He can also do arithmetic. Socrates elicits these answers from him without teaching him. He gets him to think mistakenly that a square whose sides are doubled will be double, rather than quadruple, the original size. He wants to know how to draw a square with an area of eight square feet. He tricks the slave again. Since 8 is half 16 and twice 4, it would seem that one could add one foot to the two-foot side of the four-square-foot square. But this yields a square of nine square feet. Socrates asks whether the length, then, is less than three and greater than two. He agrees, but says he doesn't know what the exact length is. Socrates comments that the slave started out by thinking he didn't know, then thought he did, then relapsed into thinking that he didn't know. But he is in a better position, and he has not been harmed by having been made2 perplexed and numb.

Socrates then builds up a figure with three squares and a corner missing, and asks if the diagonals cut the squares in half. Counting up 1/2x4 four times gives eight, the desired answer. All the slave's opinions were his own. He didn't know beforehand, so the "opinions were in him" (85c). The conclusion is that "the man who does not know has within himself true opinions about the things that he does not know" (85c). This is recollection. He has not learned these things in the present life, so he learned them at another time, when he was not a human being. The conclusion is that the soul can look for what it does not know at present.

Socrates tries to steer the discussion back to what virtue is, but Meno wants instead to try to determine whether it can be taught. Socrates agrees, even though it is an inquiry "into the qualities of something the nature of which we do not yet know" (86d-e). He does ask to be able to answer the question in terms of a hypothesis. That is, what would virtue have to be like if is to be teachable?

First, it would seem that it would have to be knowledge, since "men cannot be taught anything but knowledge" (87c). If virtue is a kind of knowledge, it could be taught. So is it knowledge? It would be identical to knowledge if nothing but knowledge is good. Socrates makes the case this knowledge is required to make anything beneficial, so it is always present when the good is: "all the qualities of the soul are in themselves neither beneficial nor harmful, but accompanied by wisdom or folly they become harmful or beneficial. This argument shows that virtue, being beneficial, must be a kind of wisdom" (88d).

So are the good good by nature? It seems not, because then they could be spotted as youths. It would seem to follow that they are taught to be good, but there is a problem with this. The problem is not with the hypothesis, if virtue is knowledge, then it is teachable, but rather with the antecedent. Socrates holds that if virtue is knowledge, then there should be teachers of virtue.

Anytus, a moderate and well-regarded man, joins the conversation. Socrates asks who would train the teachers of virtue, in the manner in which physicians train physicians. Anytus would not send those who wished to learn virtue to the sophists, though they "claim the knowledge to benefit one," because instead only corrupt them (91c). Protagoras has made a lot of money, but no one has noticed that he corrupts people and sends them away in a worse moral condition. Anytus says this is because his students and their relatives are mad. He admits that he has no experience of a sophist. So how does he know?

Anyway, Socrates asks who should be entrusted to teach virtue, and Anytus replies that any gentleman good at public affairs will do. Do they know how to pass their knowledge along? How about the good Themistocles? He taught his son horsemanship but the son turned out to be corrupt. This indicates that he did not have the skill to do so. Other examples are given. They teach their sons what would cost money to teach but do not teach them what they could teach for free. These people disagree about whether virtue can be taught, and this disqualifies them from being teachers of virtue.

What about the sophists? Meno cannot tell whether they are teachers or not. The poet Theognis contradicts himself on the subject. This phenomenon does not occur for any other subject (95e-96a). So there are no teachers, and so no learners. The conclusion is the virtue cannot be taught.

Socrates states that people are successful even when not under the guidance of knowledge, as when someone who only has a true opinion about the way to Larissa can successfully take people there. Correct opinion is no less useful than knowledge. Meno agrees, but states that knowledge will allow one always to succeed. But, Socrates counters, someone with right opinion will always succeed so long as his opinion is right. So why is knowledge prized? It is because it is stable, unlike the statues of Daedelus, which run away if not tied down. True opinions don't stay long and are not worth much "until one ties them down by (giving) an account of the reason why" (98a). That is recollection.

Socrates admits that he is guessing about the nature of the distinction between knowledge and right opinion, but not that the two are different. This is one of the few things to which Socrates would claim knowledge.

Right opinion is just as good as knowledge in guiding the course of action. The good man is beneficent. Neither right opinion nor knowledge come by nature. And they cannot be taught to be good. So virtue does not seem to be knowledge. So Themistocles and others cannot teach their sons virtue because virtue is not knowledge, not something they can pass on. They follow the right course through true opinion, which descends on them, as a gift from the gods.

It would be good to investigate now what virtue is, but it is time for Socrates to go.