Alan Saunders: Hello, I'm Alan Saunders and on ABC Radio National this is The Philosopher's Zone .

And today, we're returning to a question we posed last week: how can we acquire knowledge? If you don't know, how do you know you don't know? And if you find out, how will you know that whatever you found was what you needed to know?

This is the subject of Plato's Dialogue, The Meno . Now, as with all Plato's Dialogues, the star of the show is not the character who gives it its title, but Plato's teacher, Socrates, and one of the questions that arises here is whether the words the pupil puts in the teacher's mouth are the sort of words the teacher would ever have spoken in life. There's a third character, a slave who, under Socrates' questioning, turns out to possess more mathematical knowledge than he ever knew he possessed.

Well, to talk about The Meno and act out a little of it, I'm joined by Paul Comrie-Thompson, an independent scholar, and Rick Benitez, Associate Professor in the Philosophy Department at the University of Sydney, who begins with a bit of historical context.

Rick Benitez: Well, the rough date is probably about 427 or so BC, it's well before the trial of Socrates, but there is an allusion to the trial of Socrates in the Dialogue. The character of Socrates is very much Socratic in this Dialogue, but the passage that we're going to be looking at about knowledge, really represents an addition of new thinking on Plato's part, because it involves a whole dimension of metaphysics, and we generally don't think that Socrates went in for deep metaphysics.

Alan Saunders: So Socrates' major concern was with ethics, how life should be lived, which is what got him into trouble; that was why he ended up being tried and executed, but Plato goes beyond this, Plato has other interests.

Rick Benitez: That's right, and in terms of what you said at the start too, Socrates went as far as to try to point out, to uncover for people, how much they didn't know, where they thought they knew. But Plato tried to take it a step further and show how much they knew that they didn't know they knew.

Alan Saunders: OK. Well, let's read some of this Dialogue. Now there are three characters: there's the boy, and I'm going to be playing the boy; and Comrie, you're going to be playing Meno; Rick, who's Meno?

Rick Benitez: Meno is a visitor to Athens, and he comes from Thessaly. He's a rich person, he's got many, many servants, have come with him, and he's dressed up very finely, and he's a disciple of the Sophists, who were purveyors of wisdom in ancient Athens, and particularly of a Sophist by the name of Gorgias, who claimed to know what virtue was and Meno thinks he knows because he's heard from Gorgias.

Alan Saunders: OK then. Now Meno is addressing Socrates. Paul, take it away.

Meno: And how will you inquire, Socrates, into that which you do not know? What will you put forth as the subject of enquiry? And if you find what you want, how will you ever know that this is the thing which you did not know?

Socrates: I know, Meno, what you mean. But just see what a tiresome dispute you're introducing. You argue that a man cannot enquire either about what he knows, or about what he does not know. For if he knows, he has no need to inquire, and if not, he cannot, for he does not know the very subject about which he is to enquire.

Meno: Well Socrates, is not the argument sound?

Socrates: I think not.

Meno: Why not?

Socrates: I'll tell you why. I've heard from certain wise men, and women, priests and priestesses who made it their business to give explanations of the things they know, and they say that the soul of man is immortal, and at one time has an end which is called dying, and at another time is born again but is never really destroyed. The soul then, being immortal and having been born again many times and having seen all things that exist, whether in this world or the world below, has knowledge of them all, and it is no wonder that it should be able to call to remembrance all that it ever knew about virtue, and about everything for, as all nature is akin, the soul has learned all things, there is no difficulty in it eliciting, or as people say, learning, out of a single recollection.

Meno: Yes, Socrates, but what do you mean by saying that we do not learn, and that what we call learning is only a process of recollection? Can you teach me how this is?

Socrates: It'll be no easy matter, but I'll try to please you to the utmost of my power. Suppose that you call one of your numerous attendants that I may demonstrate with him.

Meno: Certainly. Come hither, boy.

Socrates: He's Greek, and he speaks Greek, does he not?

Meno: Yes indeed, he was born in the house.

Socrates: Attend now to the questions which I ask him, and observe whether he learns from me or only remembers.

Meno: I will.

Socrates: Tell me, boy, do you know that a figure like this is a square?

Boy : I do.

Socrates: And do you know that a square figure has these four lines equal?

Boy : Certainly.

Socrates: And these lines, which I have drawn through the middle, one vertical, one horizontal, touching the middle point of each side, these lines are also equal.

Boy : Yes.

Socrates: A square may be of any size?

Boy : Certainly.

Socrates: And if one side of this figure be of two feet and the other side be of two feet, how much will the whole be?

Alan Saunders: What happens next is not so much complex as a bit long-winded. So here's a summary.

In response to Socrates' questions, the slave establishes that a square with sides 2 feet long will have an area of 4 feet, and that a square twice as large will have an area of 8 feet. But how long do the sides of a square have to be if its area is 8 feet?

The slave guesses that if an 8 foot square is twice the area of a four foot square, then the sides will need to be twice as long. But twice 2 is 4, and 4 times 4 is 16, not 8, so there must be something wrong here. A square with an area of 8 feet must have sides longer than 2 feet but not as long as 4.

The slave has a stab at 3, but of course 3 times 3 is 9, not 8. So how long, Socrates asks, does the side have to be?

Boy : Indeed, Socrates, I do not know.

Socrates: Do you see, Meno, what advances he has made on the path to recollection? He did not know at first, and he does not know now, what is the side of a figure of 8 feet. But then he thought that he knew and he answered confidently as if he knew, and he had no difficulty, but now he has a difficulty, and neither knows, nor fancies that he knows.

Meno: True.

Socrates: Is he not better off in knowing his ignorance?

Meno: I think that he is.

Socrates: If we have made him doubt, have we done him any harm?

Meno: I think not.

Socrates: We have certainly, as would seem, assisted him in some degree to the discovery of the truth and now he will wish to remedy his ignorance. But then he would have been ready to tell all the world, again and again, that the double area should have a double side.

Meno: True.

Socrates: But do you suppose that he would ever have enquired into or learned what he fancied that he knew, though he was really ignorant of it until he had fallen into perplexity under the idea that he did not know, and had desired to know?

Meno: I think not, Socrates.

Socrates: And at present, these notions have just been stirred up in him, as in a dream. But if he were frequently asked the same questions in different ways, he would know as well as anyone at last.

Meno: I daresay.

Socrates: Without anyone teaching him, he will recover his knowledge for himself, if he is only asked questions.

Meno: Yes.

Socrates: And this spontaneous recovery of knowledge in him is called recollection?

Meno: True.

Socrates: And this knowledge, must he not either acquire it or always possess it?

Meno: Yes.

Socrates: But if he always possessed this knowledge he would always have known, Or, if he has acquired the knowledge he could not have acquired it in this life, unless he has been taught geometry. For me may be made to do the same with all geometry and every other branch of knowledge. Now has anyone ever taught him all this? You must know about him if, as you say, he was born and bred in your house.

Meno: And I am certain that no-one ever did teach him.

Socrates: And yet he can solve this problem and obtain the knowledge.

Meno: The fact Socrates, is undeniable.

Socrates: But if he is not taught the knowledge by anyone in this life, then he must have had it in him and learnt it at some other time.

Meno: Clearly, he must.

Socrates: Which must have been the time when he wasn't a man.

Meno: Yes.

Socrates: And if there have always been true thoughts in him, both at the time when he was and was not a man, which only need to be awakened into knowledge by putting questions to him, his soul must have always have possessed this knowledge, for he always either was or was not a man.

Meno: Obviously.

Socrates: And if the truth of all things always existed in the soul, then the soul is immortal. Wherefore, be of good cheer and try to recollect what you do not know, or rather, what you do not remember.

Meno: I feel somehow that I like what you're saying.

Socrates: And I, Meno, like what I'm saying. Some things I've said of which I'm not altogether confident, but that we shall be better and braver and less helpless if we think that we ought to enquire, then we should have been, if we indulged the idle fancy that there was no knowing and no use in seeking to know what we do not know, that is a theme upon which I am ready to fight in word and deed to the utmost of my power.

Alan Saunders: And from that point in the Dialogue, Rick, now having brought the Boy to the stage where he knows that he doesn't know, Socrates continues the d ialogue, continues to question him, and elicits the right answer from him.

Rick Benitez: That's right.

Alan Saunders: Well, I want to know - perhaps I could ask you, Rick, what is the object of this Dialogue? You see it looks to me as though you could read it simply as an attempt on the part of Plato to prove that there's an afterlife; that knowing is rediscovering something that you learnt in an earlier existence, and would presumably take into another existence after your death.

Rick Benitez: Well that's right. I think though that there are really two primary functions of the Dialogue, and it goes back to the question you asked earlier about Plato and Socrates. There's one ethical function or pragmatic function of the Dialogue, which is about going around thinking that you know, when you don't really know. And that's a very Socratic theme. The function of the Dialogue is to try to awaken people up to the pragmatic necessity of trying to examine yourself. Then there's the platonic function, which is trying to show that there is an afterlife, that the soul is mortal, and that you really do have a kind of storehouse of knowledge in your mind, from birth.

Alan Saunders: Paul Comrie-Thomson, I remember reading this Dialogue when I was a student, and my immediate thought was that I was being had here and that these questions put by Socrates in the Dialogue were leading questions. What do you think of the way in which Socrates exchanges with the Boy, with the slave?

Paul Comrie-Thompson: I think there's an interesting sub-text going on here - reading this Dialogue over 30 years now, coming back to it. Meno's slave really comes across to me as someone who is gifted in mathematics, and the way this Dialogue is constructed is a perfect example of how one teaches someone who has a gift in a certain area. They are leading questions but they're given in a way that will draw out someone's intuitive understanding, until the slave reaches a point where intuitive understanding of mathematics will no longer work, where he has to work out the square root of 8, and he sort of has a guess and says, 'Well I think it's 3'. But that's not something you can do with intuition. But up to that point, I think the questions are leading because we are being shown how knowledge is drawn out of someone, intuitive understanding is drawn out of someone by the right sort of question.

Alan Saunders: But if that's the case with the Dialogue then it fails, doesn't it, in doing the two things that Rick has said it is doing. Because in order for it to serve the purpose that Rick thinks it has, surely you don't want a gifted slave, you want a man in the street, a slave in the street, or in the Agora or something like that.

Paul Comrie-Thompson: The primary question here is: can arete be taught.

Alan Saunders: That's a virtue, is it? Well, Rick's the Classical scholar, you can tell us.

Rick Benitez: I think excellence is probably the best translation of it.

Alan Saunders: OK, Paul.

Paul Comrie-Thompson: Excellence, and another word I thought might fit here is flourishing. Now every person has the area, it's been said in this Dialogue, in which they can flourish. Meno's slave has a particular arete in the field of mathematics, but for other people it could be music, it could be oratory, it could be something else. So the principal argument does not collapse because this is, I'm suggesting, perhaps someone who's gifted in mathematics. Everyone has their arete, the area in which they can flourish, but it has to be discovered and then it has to be developed.

Alan Saunders: So Socrates has got lucky. He happened to choose a slave whose arete was mathematics, at random from Meno's slaves.

Rick Benitez: I don't think that's actually the case, Alan. I'm neither here nor there that whether the slave is actually gifted in mathematics, but let's say that he is. I think that the way the Dialogue runs, Socrates' supposition is that everyone's gifted in mathematics. What the slave has especially that Meno lacks, is innocence. He answers in the way that he thinks, he follows Socrates' directions, and he tries to say what he believes the answer is. Meno's sophisticated, Meno wants to give the kinds of answers to questions that the right people give, and that the important people think. So he wants to be up on 'the spin', the latest thing. The slave has nothing of that, but it's very interesting that Socrates does pick a slave to try to show this up to Meno, I think.

Alan Saunders: So when you say that Meno is sophisticated, you mean that both in the colloquial sense of the term and in the literal sense of the term, in as much as he is a pupil of a Sophist. Perhaps you might just tell us who the Sophists were; what was their problem?

Rick Benitez: Well the Sophists were people who taught wisdom of various kinds for a fee. Some of them taught technical subjects but some of them taught political and moral subjects and so they professed to be able to teach virtue, and this was one of the things that concerned Socrates very much, because if they could teach it and charge very large sums of money for it they must know what they're talking about, but every Sophist he ever enquired with about virtue, didn't show up to know what they were talking about.

Alan Saunders: Do you think that the historical Sophists are getting an unfairly bad wrap in Plato's Dialogues? Because you're suggesting really that they just told you what would sound good. Is this unfair to them?

Rick Benitez: I think it's somewhat unfair. I think what happens is that a vast number of people who profess to teach virtue and things like it, for a fee, are all lumped together by Plato as, if you want, ratbag philosophers, and that is tarring too many people with the dirty brush. Some of the Sophists, like Protagoras and even Gorgias, had rather sophisticated views, not in the literal sense, but subtle views, and interesting views, interesting philosophical views that Socrates largely ignores and doesn't pay significant enough attention to.

Alan Saunders: Well Comrie, Rick is telling us that the major feature of the slave boy that makes him useful for Socrates is his innocence, rather than his gifts. What do you think of that?

Paul Comrie-Thompson: Interesting, because the capacity to be amazed, educational psychologists tell us, is very, very important. If you have very young kids who say, 'Gosh, look at that, isn't that extraordinary?' that childlike bafflement that unfortunately when people say, get to university and they become sophisticated, cool undergraduates, they lose a lot of that, and I think in the Dialogue and also in educational psychology, it's very important. The lack of pretension that enables you to say, 'Gosh!' or even to admit that you're baffled, is very, very important, and I think this comes through in this Dialogue. If you're going to learn, be prepared to be amazed and be prepared to admit that you're amazed, even if the sophisticates say, 'Oh, you're not amazed by that, are you?' and also to admit you're baffled. When the slave says 'I just don't know, Socrates, I just don't know. I've got this far, but no, I don't know', that's the way to knowledge rather than petulantly sort of storming off and saying, 'Well this is just a rigged question.'

Alan Saunders: That was something, wasn't it Rick, that Socrates himself was good at, or appeared to be good at. I wonder whether this is one of the things that annoyed people about him, and possibly led to his trial and execution, that he looked innocent; he made a big thing about not knowing anything, and then of course ran rings around people when he was arguing with them.

Rick Benitez: That's right. He knew more than they did by far through his own explorations of those ideas. And even for the kind of more abstract thoughts he had about the way in various beliefs might fit together, but logically whether they were consistent with one another or contradictory. Very often people didn't think much about whether - the people Socrates was speaking to - whether they held contradictory beliefs, they couldn't flesh out the contradiction in them, and he was good at ferreting that out. But whether or not he really knew substantial matters about which he asked is still a question that scholars debate, and there are a lot of people that think Socrates is sincere about not having substantial knowledge about the things he's enquiring into.

Alan Saunders: But I was left with a couple of questions after our little enquiry. This slave, for example: he might have been mathematically gifted or he might have been an everyman character, but was it common in ancient Athens for slaves to be depicted in such a favourable light?

Rick Benitez: Oh no, I don't think it would be customary at all. One of the things, however, is that Socrates is a very radical person and he shows people in lights in which they aren't customarily shown. For example, he shows the aristocrats in lights contrary to the one in which he reveals the slave to be, that is, he brings them down, and that's not customary either. He shows a very small amount of tact in doing that.

Alan Saunders: And he's also taking the slave through this educative process and it's clear that he believes that the slave is undergoing something that is good for him. So there's a notion here of doing something good for a slave, which again I assume is unusual.

Rick Benitez: Well I think Socrates believed that that kind of dialectic that he engaged people in was good for them all, and the main thing that he's really trying to show is that it's good to discover your ignorance. But I understand your question now: he's benefiting the slave, and why would people have cared so much about doing good for someone who has no rights and things like that. And I think that's an interesting point; I haven't seen it come up before.

Alan Saunders: Is it because the slave, in accordance with Pythagorean views, might have been somebody else in a previous life and might be somebody else in the next life?

Rick Benitez: Well, the Pythagoreans did believe, they're probably the first among the Greeks to believe in reincarnation, and they believed that human souls could migrate between other human beings across generations, and even to animals. So they didn't eat meat, they were among the earliest Western vegetarians.

Alan Saunders: And famously, didn't eat beans.

Rick Benitez: Didn't eat beans either, though the reasons for that are very vague, very uncertain.

Alan Saunders: Now apart from the slave in the Dialogue, there's also the character of Meno. Meno was a real person, wasn't he?

Rick Benitez: Yes, Meno was a real person. He was a nobleman from Thessaly. I think Plato's readers would have been well aware who he was, and even what happened to him in the end.

Alan Saunders: What did happen to him in the end?

Rick Benitez: Xenophon tells us about Meno's life in the work called Anabasis. He was with the Greeks on the voyage into Persia, the Greek Army, and he was treacherous there and he betrayed the Greeks, and Xenophon tells us that Meno was avaricious and so he apparently got a good offer from the Persians and he betrayed them to their great detriment, and the whole rest of the story of the Anabasis that Xenophon tells us about the great retreat of the Greek Army for a very long time, back from Persia.

Alan Saunders: With that wonderful moment when they finally reach the seat, 'Thalassa, Thalassa, the sea, the sea'.

Rick Benitez: That's exactly right, yes. So Meno has a lot to do with why they had to retreat, and yet the Persians didn't trust him after he betrayed his own people either and he was eventually imprisoned and he was tortured and he was put to death at the end of a year.

Alan Saunders: That was Rick Benitez on the sad end of Meno, and this week you also heard Paul Comrie-Thomson.

Meno's name lives on in books about philosophy and in Plato's Dialogue, the full text of which you will find linked to on our website.