Theaetetus

"Yes, it’s a book length introduction and it’s a major work. Plato’s Theaetetus asks what knowledge is, and several possible definitions are explored in depth and eventually dismissed, though considerable progress is made. In the opening sections of the dialogue, which look at the theory that knowledge is perception, Socrates and Theaetetus explore the ideas of both the Presocratic philosopher Heraclitus and his theory of flux, and also those of Protagoras and his theory that each individual human is the measure of all things, of things that are, that they are, and of things that are not, that they are not — the strong version of Protagorean relativism that we were discussing just now. Plato brilliantly shows that there is a very powerful natural link between Protagorean relativism and the Heraclitean view that all is flux, because if your view of the world is that everything is always flowing, always in motion, always changing, and nothing is ever still, then there could be no stable, objective, universal knowledge to get hold of. Knowledge could only be perspectival to the particular perceiver in time and space – except that the perceiver, of course, is also always flowing, always changing, their sensory organs are always changing…so in what sense could you have even individual perspectival knowledge? Plato shows the connection between a Heraclitean metaphysical view of the phenomenal world — we are not talking here of Heraclitus’s belief in an underlying Logos which regulates the flux — and an epistemological view which says that extreme individual relativism is the only kind of ‘knowledge’ that we could possibly have. Burnyeat writes about this with great insight in his introduction: it is the most detailed, thoughtful, and challenging exploration of Protagorean relativism and how it connects to Heraclitean flux that exists. He writes about the whole dialogue, and there are many other theories about knowledge in the dialogue, but in terms of the early Greek philosophers, Burnyeat’s profound exploration of Heraclitus and Protagoras is really wonderful. It’s real philosophy. It shows how a modern philosopher can take an ancient text and do genuine creative philosophy with it. He’s also a clear and good writer, but I won’t pretend it’s the easiest read, simply because the ideas involved are difficult and you have to concentrate. He takes you through different interpretations of positions and different arguments for and against those interpretations, and you have to hold your ground and keep focused. But it’s so rewarding and so worthwhile. Absolutely. In the Theaetetus , Plato himself is very interested in this question. He says that you can’t actually put extreme Heraclitean flux into language as we understand it because that would involve using words like ‘is’ — but there would be no ‘is’ if everything is always in a state of becoming. And you can’t even say ‘everything is in a state of becoming’ because you’ve said ‘everything’ and you’ve said ‘is’. You can’t say ‘white is always changing’ because what would ‘white’ be? There would be no ‘white’. Plato says we’re going to need a new language in which to express Heraclitean flux, and he further suggests that extreme Protagorean relativism can’t be put into words at all, because if you say ‘all knowledge is relativistic’, that itself is an objective claim — a claim that you’re putting forward as a universal, objective truth. Burnyeat is very interesting on all this. Similar ideas, I would add, also emerge in Plato’s Parmenides , a dialogue about the Presocratic philosopher Parmenides who argues that there is just one thing, being – there are no divisions in reality, there is simply one thing that’s being. Again, Plato argues that that theory cannot properly be put into words either – you can’t name or describe the One; you can’t even say that the One ‘is’, since it does not exist in time. It can’t be thought or known at all. (And I’m sure that Plato is aware of the irony of making even these negative claims about it.) So, Plato is just so fresh and radical and relevant to modern thinkers in the way he explores these issues of what philosophy is. Can every philosophical position be put into words, and if it can’t, can it still be considered a philosophical position? Is philosophy something which has to be expressed in language? These are questions that have particularly caught the imagination of some philosophers in the last sixty years or so, and Burnyeat is wonderful on them. Absolutely. I will go out on a limb and say you cannot properly understand Plato unless you have read some Heraclitus and Parmenides and thought hard about them. Plato is also, as we’ve seen, very interested in Protagoras and some of the other sophists and other Presocratics such as Zeno, who appears to deny the possibility of motion, and Democritus who says that everything is only atoms and void. But above all he’s fascinated by Parmenides, the philosopher of being, and Heraclitus, the philosopher of flux and motion, at least so far as the sensible world goes (again, the changing phenomenal world is for Heraclitus ordered by the Logos). What’s so interesting is that Aristotle, who of course studied with Plato for many years and knew him very well, tells us that as a young man Plato became acquainted with Cratylus and Heraclitean beliefs. Cratylus had been a student of Heraclitus — whether he was a real student or just a follower we don’t know — but he was even more extreme than his master. Heraclitus says something along the lines of ‘you can’t step into the same river twice’ — that’s the famous quote, though whether he said it in precisely those words we can’t be sure (Plato says he said it in those words). Cratylus, however, says that you can’t even step into the same river once because if everything is always flowing then identities can’t even come to form. It’s not just that flux and change break down identity, they stop identities being created: you can’t step into the same river once because there would be no ‘you’ and no ‘river’. Later on Cratylus apparently stopped speaking to his students altogether and would just move a finger! He’s my hero. I love Cratylus. Now, Plato, according to Aristotle, thought that Cratylus was telling the truth about the sensible world, about the world of appearances. According to Aristotle, to the very end of his life Plato never lost that extreme Heraclitean view of the sensible world, the phenomenal world. He thought that this is a world of becoming, a world of change. Now, because Plato also thought that knowledge had to be in relation to being — to a fixed, stable object — Plato thought this phenomenal world could not be an object of knowledge. It was not available for knowledge. At the very best, you could have a true opinion about it, but you could not have genuine knowledge of this world. “Protagorean relativism can’t be put into words at all, because if you say ‘all knowledge is relativistic’, that itself is an objective claim.” Therefore, if there is to be knowledge at all and if you’re going to avoid scepticism — and Plato is very keen that knowledge should exist — then there’s got to be another realm which is stable and which can be known. So Plato deduces that there must be another realm, and that there are these eternal, unchanging, non-sensible, perfect entities called Forms, such as the Form of the Good and the Form of Beauty. Plato’s famous theory of Forms — a metaphysical theory — actually comes from his epistemology: it comes from his belief that this world is in flux and can at best only be an object of opinion, not knowledge. He could have given up at that point and said that there is no knowledge, as Protagoras seems to have done, but Plato was determined that knowledge should exist and so says that it is of another realm. Of course, we might want to take issue in terms of the way Plato distinguishes knowledge from belief in relation to their fields rather than their reliability, but that is a discussion for another time. The point in relation to the Presocratics is that if you go through the main argument for the theory of Forms at the end of Republic V, you can see the powerful influence of both Heraclitus and Parmenides. Both philosophers are used by Plato in very precise ways in the construction of his argument for Forms. Firstly, Plato takes Parmenides’s argument — Do you think something or nothing? You’ve got to think something. Do you think something that is or something that is not? You can only think something that is etc. — and then goes on to say that this ‘is-ness’ is the object of knowledge, and it can only be this Parmenidean ‘is-ness’ that is the object of knowledge, but it can’t exist in this world because this world is Heraclitean, therefore there’s got to be another realm. So he’s blended Parmenides and Heraclitus in Republic Book V to come up with his theory of Forms. And you see this throughout Plato: he’s greatly influenced by many of the philosophers who came before him, but particularly by Parmenides and Heraclitus."

"The Socrates of the Theaetetus looks more like the Socrates of the Apology than the Socrates of the Republic , which many think was written between the Apology and the Theaetetus . The Socrates of the Republic is in control, and takes the main role in the elaboration of what is said; and although what is said there is often marked as tentative or provisional, the dialogue is not one that ends in impasse, or aporia. The Theaetetus , by contrast, provides what seems to be a thoroughgoing impasse, and descriptively reminds us of the represented figure of Socrates as we saw him in The Apology and some of the earlier works. But that makes us think rather harder about the Theaetetus itself — how it is constructed and whether the Socratic representation is here integrated with the heavy-duty arguments about knowledge. Support Five Books Five Books interviews are expensive to produce. If you're enjoying this interview, please support us by donating a small amount . The great contemporary translation of the Theaetetus is by M J Levitt, with a magisterial introduction by Myles Burnyeat, which makes clear the deep philosophical significance of this dialogue – and its utterly puzzling nature. The Theaetetus begins with a long account of who Socrates is, how his mother was a midwife, and how he himself doesn’t propose theories: he deals with people who are ‘pregnant’ in mind, and figures out whether they have real ideas or ‘wind eggs’. So this opening offers a theme and variations on the figure of Socrates offered by the Apology , or the Euthyphro , or the Laches , focussing on how we go about philosophical discussion, how we tackle philosophical enquiry, and how we engage with each other. That is succeeded by some very dense argument about whether knowledge is perception, interrupted by a six-page digression on the nature of the philosopher, presented as a hopeless dunderhead who falls into wells because he isn’t looking where he’s going because he is too busy trying to liken himself to god. Then some even more dense argumentation on knowledge and belief ends the dialogue in a final impasse. “He deals with people who are ‘pregnant’ in mind, and figures out whether they have real ideas or ‘wind eggs’ ” Ultimately, the dialogue provokes many more questions than it solves (about knowledge, about the structure of reality, about the nature of perception); but it also offers a challenge in its representations of Socrates: why is all this sharp argumentation bracketed by these twin passages on the nature of the philosopher, or the representation of this philosopher in particular? And why does Plato – interested as he clearly is in the representation of a philosopher, whether an historical figure or a stereotype – juxtapose that rich material here to the highly abstract discussions of knowledge and reality. Why, here, do we need to think about Socrates’ barrenness of ideas, or his engagement with other people, or the solitary enterprise of the philosopher who seeks to become like god? We seem to have a series of different paradigms here, some of them identified with Socrates and some identified with other figures Socrates produces for us – but all of them are somehow inconclusive. The inconclusiveness of these models of philosophy mirrors the inconclusiveness of the dialogue, and invites the reader to think not only about knowledge and ignorance, and how we are disposed towards them, but returns us, in the figures of the philosophers, to the question of how that sort of inquiry is, or should be a part of a life. The representations of Socrates, even in this austere discussion of knowledge and belief, still invite us to ask ‘how best to live?’. This happens in Plato’s writing over and over again: he uses the context of the formal arguments to kick the discussion upstairs, making you think about principle rather than the particular argument in question. The Theaetetus is the most extraordinary version of that. It’s also quite funny. Many people suppose that we should think about Plato’s development psychologically. The idea might be that the young Plato tremendously admired Socrates, so in his early works he represents Socrates doing philosophy (as it were, the ‘historical’ Socrates), then suddenly when Plato wanted to say something on his own behalf, the character ‘Socrates’ became a kind of coat peg to hang those ideas on, so that in those dialogues ‘Socrates’ really means Plato. That is indeed a sustainable view, if somewhat naïve, psychologically speaking. I think it may be undermined, though, by the features of the Theaetetus I was mentioning, as well as by the connections between the Theaetetus and other dialogues – Apology, Phaedo, Republic, for example. “Representations of Socrates invite us to ask: How best to live? ” For the Theaetetus is much more reflective than it is dogmatic – in thinking about the figure of the philosopher, it makes us think about the two paradigms at once, and ask whether either is the right way of going about things. The whole dialogue, on that account, is reflective, both on accounts of what knowledge is, and on accounts of what it would be to live one’s life with one’s values orientated towards knowledge – to live as a lover of wisdom, a philosophos. But reflectiveness like this is not the same as scepticism – the running puzzles and impasses and uncertainties of the dialogues, and of the figures represented in the dialogues, are not, I think, just an enormously sophisticated system of scepticism. I don’t think that’s what’s going on. Rather Plato repeatedly puts the paradigm (of knowledge, of philosophy) up and makes us see how the paradigm might fail. The purpose of that, in my view, is to make us think about the paradigm, rather than make us think that knowledge is impossible and that we should just go and sit in a barrel. I don’t think the arguments in the Theaetetus conclusively undermine what is said in the Republic, but they do allow us to take a critical view of it. It’s like the difference between a treatise that gives us a philosophy and something that does philosophising with us. There is a lot more of the second in Plato than we might think (or the tradition would have us believe). Indeed, he often sets up a critical relation between one dialogue and another, again perhaps to make us reflect on the arguments and claims they offer, rather than to demand commitment to some particular thesis or another. So it may be well worth thinking about a triangular relation between the figure of the philosopher in The Apology, the Socrates figure of the Republic, and the two philosopher figures given in the Theaetetus, in the context of the Theaetetus question about whether we understand what knowing is, the conditions we put on knowledge: is it true belief, true belief with an account, or perception? “Plato repeatedly puts the paradigm (of knowledge, of philosophy) up and makes us see how the paradigm might fail” There’s a trope, repeated throughout the Platonic corpus, in which Socrates admits that he doesn’t know about a particular topic, but at the same time does say that he recognises some conditions that must be put on any adequate answer. You get stuck trying to give a general account of what, for example, beauty is, but Socrates suggests conditions that must be put on the answer. One of the things that Plato makes clear in the process is that that is largely what philosophy does: it doesn’t just come up with first order answers, it thinks about what the constraints are on the those answers. Philosophical enterprise is at that level: at the level of thinking about thinking. But we can miss that in Plato, if we miss what’s going on with the figure of Socrates in his dialogues."