Boy am I behind on this! I am now most of the way through the Sophist, but am just now finding time to do a quick post on the Theaetetus, which I can by no means do jusice to. It is an extraordinary dialogue, one which I intend to return to repeatedly. It’s also one of the first I’ve ever read where I’m actually engaged by the philosophical material. It’s about knowledge.Socrates here questions a young man called Theaetetus, trying to help him come to some conclusion about what knowledge is. (This is where Socrates claims to practice mid-wifery with young men and their ideas; he himself is barren but he helps his interlocutors give birth to ideas, and then tests them to see if they are sound or simply “wind-eggs.”) They try three definitions: that knowledge is perception; that knowledge is true opinion; and that knowledge is true opinion with an account. Each is rejected.
The dialogue is way too complex and interesting for me to even begin to list all my questions about it. It’s extremely appealing, in that Theaetetus is such an intelligent and willing interlocutor (as opposed to the dim or hostile or otherwise irritating ones). It also has one of the most charming bits I’ve ever read in Plato, where Socrates proposes that the brain is like an aviary, with bits of knowledge flying around in it like birds. This is to try to explain how mistakes can arise: presumably one may have captured a bird and put it in the aviary at some earlier time, but be unable to get hold of it when it’s needed. My brain’s just like that!
But the dialogue was especially interesting to me because, like many of my students, one of the general objections I have to Plato is his belief in an absolute truth. I am less certain that there can be any such thing, and more inclined toward a position closer to relativism. Thus it is nifty to see Socrates explicitly making an argument against relativism here (as he somewhat sneakily makes the first definition — knowlege is perception — into Protagoras’ doctrine that man is the measure of all things).
One part of the argument is the observation that not everyone will believe that Protagoras’ doctrine is true. But Protagoras must believe that, if I think he is wrong, then he is wrong to me, and thus he is wrong. (I think that’s how the argument goes…) The notion that knowledge is simply perception he refutes by pointing out that there is knowledge without perception (memory), and that one reasons concerning perceptions (e.g. comparing soft to hard, or cold to hot) without the use of the perceptions themselves; thus knowledge must be something different from perception.
I haven’t succeeded, I’m afraid, in conveying how really interesting it is to think about just what knowledge actually is! But the other remarkable thing about the dialogue is that the whole thing is being read out loud by a slave boy from a book written much earlier by someone called Eucleides. He has just seen Theaetetus, wounded and suffering from dysentary, being carried to Athens, and is thus reminded of the account of this conversation between Theaetetus and Socrates which he wrote down some time ago. The dialogue ends without returning to this frame. But surely it casts some light forward onto the dialogue that follows, about knowledge. Terpsion, listening to the slave read the account, has no direct perception of Theaetetus and Socrates, yet he must gain some kind of knowledge about them (as do we, as we read the dialogue). Does he gain true opinion, or the ability to give an account of his opinion? Plato doesn’t show us.