HoPwaG: Plato IV (Theaetetus)

Question of whether there are things--or everything--such that they are x for me but y for you. That is, there is a relativist theory of truth. Theaetetus explores this question, and other epistemological questions: how false belief possible, etc.

Theaetetus himself features, as does Theodorus, as offering definitions of knowledge.

First pass:

• Theaetetus suggests that knowledge is perception (aisthesis)-- can include sensory and 'mental' perception; we know something when we perceive it;
• Socrates' reply: this suggests that what seems to be case is the case for me; if perception is knowledge, then, e.g., I could know that it is warm and you could know that it is cold. That seems wrong: it entails that truth is relative, since can only know x if x true.
• Note this is what the Sophists endorse (you are the "measure" of how the wind is for you) and Heraclitus (universal flux |= relativism, since no stable existence for anything, so everything changes from moment to moment, and all we have is reports from moment to moment);
• Defense of the relativist thesis: if you're interested in what's good, you just are interested in what's good for you, and the relativist can tell you that! What would it mean to be interested in what's good, but not for anyone, asks, e.g., Protagoras?
• Bad reply to relativist: there are thermometers! But then the relativist can just say that perceptions of the thermometer are not stance-independent, etc.;
• Socrates' replies: (1) relativism denies expertise; (2) questions of future; (3) relativism fails on its terms--it's self-refuting.
• Possible weakness of Socrates' reply (3): Protagoras might have only to admit that the doctrine is false for Socrates, but not false simpliciter.

Abandoning that Sophistical answer to the "knowledge is perception" idea, we get a puzzle about false belief:

• Theaetetus' next suggestion: knowledge is true belief;
• We then want to know: what is it for one belief to be true and another false?
• The Sophist challenge: it's impossible to have false beliefs; there is no such thing.
• The Sophist's argument: either I know x or I don't. If I know x, won't make mistake about it. If I don't know x, I won't be able to think about x, so again I can't make a mistake about it. In either case, I can't have false beliefs about x.
• Reply: As with Meno's paradox, there seems to be space for knowing enough about x to have false beliefs about it. The wax tablet picture of memory: some people get impressions quickly but lose them fast, others keep them, some don't get them easily. So, this opens door to mismatch: when there is a difference between something in the wax and a new  impression you get.
• How does this solve the paradox: I have the impression of someone in memory, and I match up a perception with that impression that just doesn't match.
• Problem: doesn't cover all cases of false judgement, e.g. saying 7+5=11. There, there's no impression being received. So how is false judgment possible? 
• Socrates' reply: soul as aviary. Acquiring knowledge is putting birds in aviary. Saying 7+5=11 is pulling the wrong bird from the aviary. So it's that you know 11 (that it's in the aviary) that enables you to get things wrong!
• Problem: it's paradoxical to say that it's because you know 11 that you can say 7+5=11. [Is the idea here: because, if you say 7+5=11, you don't know 11? I think so]
• Theatetus' amendment: the aviary also contains birds that represent ignorance. But: the point was to say something about knowing enough to get stuff wrong. Birds that represent ignorance won't solve that problem.

So we seem to be in aporia. We don't yet know that it's possible to have false beliefs, but we're considering the proposal that knowledge is true belief, and that at least still seems right. But:

• Socrates' reply: suppose jury is convinced someone guilty, and he is guilty, but they're persuaded by bad lawyering. So we don't want to say they know he's guilty.
• But knowledge does still seem to be true belief and something else.
• This a contemporary task for epistemologists.
• The new proposal: logos is what's needed in addition to true belief to get knowledge, logos being some kind of "rational account" [i.e., an account of why the true belief is true? Maybe.]
• Not fully worked out, but the Platonic proposal, such as it is, is that knowledge has something to do with what account you give of your true belief when you're asked why it's true.