Plato’s Meno is a dialogue between a young man from Thessaly (Meno) and a philosopher from Athens (Socrates). Other characters in the dialogue include a boy who is a slave of Meno, and a man who is a wealthy and influential aristocrat (Anytus).

The dialogue begins with Meno and Socrates engaged in a discussion about the nature of virtue. Meno asks Socrates whether virtue can be taught, or whether virtue is acquired by practice, or whether virtue can be acquired in some other way. Socrates answers that virtue cannot be defined. Meno asks Socrates if he has ever met the sophist Gorgias. Meno says to Socrates that Gorgias knows what virtue is and how it is to be defined, but Socrates responds by asking Meno to define virtue.

Meno replies that there are many virtues, but Socrates asks him to define what all virtues have in common. Meno says that courage, temperance, and wisdom are virtues, but Socrates says that this answer does not define what is shared by all virtues.

Meno then says that virtue is a desire for honorable things, and that it is also the power to attain them. However, Socrates disputes this assertion by arguing that if virtue is the power of attaining good justly, and if part of virtue is justice, then justice as a part of virtue is being used to define the whole of virtue (i.e. part of virtue is being used to define virtue, and virtue as a whole has not yet been defined).

Meno realizes that his previous certainty about the nature of virtue has been thrown into doubt, and that he must reexamine his assumptions about how virtue is to be defined. Socrates’ declaration of uncertainty about the nature of virtue leads Meno to the same state of uncertainty.

Socrates seems to be gratified by having cast doubt on Meno’s previous illusions of certainty, and then begins to replace these illusions with a new and unhindered spirit of philosophical inquiry. However, he is asked by Meno how it is possible for him to begin an inquiry into the nature of virtue when he does not know what virtue is.

Socrates replies that the soul is immortal, and that it knows everything that exists, because it is reborn from a previous life, and because it knows everything that existed in a previous world. The acquisition of knowledge is thus a process of remembering whatever has been learned in the past.

To prove the validity of this argument, Socrates presents a series of mathematical questions to a young boy who is a slave of Meno. Socrates asks the boy to solve a geometrical problem which requires a series of steps of reasoning. Socrates asks questions of the boy in order to lead him through the series of steps of reasoning, in such a way that the boy finds the solution to the problem. Socrates then declares that since the boy has not had previous training in mathematics, the boy must have had mathematical knowledge in a previous life and must have remembered this knowledge in order to find a solution to the problem.

Meno asks Socrates to return to the original question of whether virtue can be taught or whether virtue can be acquired in some other way. Socrates answers that if virtue is knowledge, then it can be taught. (Thus, Socrates assumes that whatever can be known can be taught.)

Socrates also says that if virtue is good, and if knowledge includes everything that is good, then virtue is (a part of) knowledge. If virtue is a quality of the soul, and if virtue is advantageous to our well-being, then it must include wisdom, since if it were used unwisely it would be harmful to our well-being.

Meno agrees, but realizes that Socrates is not yet ready to declare that virtue is knowledge or that knowledge is virtue. Socrates explains that if virtue can be taught, then there must be teachers who can teach it. But Socrates says that it is impossible to find any such teachers of virtue, or to define who can teach virtue, and that therefore it must be assumed that virtue cannot be taught. If virtue cannot be taught, then it cannot be wisdom or knowledge. Socrates concludes that virtue is neither innate nor acquired, but that it is an instinct which is given by God.

The major portion of the dialogue is concerned with the question of whether virtue can be defined, and with the question of whether virtue can be learned or taught. Is virtue the same as knowledge? Is it necessary to know what is good, in order to be virtuous? Is it possible to act virtuously without knowing what is good? If virtue does not depend on knowing what is good, how is it possible to prevent virtue from being misused? If virtue is knowledge, why do persons who have knowledge of right and wrong not always act virtuously? These are some of the questions which are presented directly or indirectly by the Meno as it discusses how to find a valid method of ethical inquiry.

Plato. Meno. Translated by Benjamin Jowett. Indianapolis: The Bobbs-Merrill Company, 1949.