This, like other Plato works, I don't recall any details. ( )

Knowing that Theaetetus is one dialogue in a trilogy with Sophist and Statesman following it, and with Parmenides prior and linked to the trilogy, and having struggled through the almost impenetrable Parmenides, I was apprehensive about Theaetetus but then pleasantly surprised when I read it. After Parmenides, Theaetetus seems like a hybrid of Plato’s early, middle and late periods (assuming this division). It’s a bit more genuine dialogue as opposed to monologue, it has more humor and irony (including several thinly veiled and cutting digs at Protagoras, similar treatment of the Heracliteans, and the familiar but always enjoyable abuse of lawyers, orators and Sophists), and has more of the literary artistry of the early and middle works, as well as something more like their topical breadth (and pleasant digressions). Also the metaphors, e.g. of the wax and the aviary, and it touches more on myth (though other late works, e.g. Timaeus and Laws, still deal with myth, sometimes extensively). But then it has the proto-formal logic, more sustained and elaborated arguments, and concerns for precision in use of terms and investigation into language that are characteristically late period. It also doesn’t mention the Theory of Forms, possibly departing from it at least somewhat, and it pretty clearly seems to depart from the earlier conception of learning as recollection of what’s already in the soul.

The primary question is, What is knowledge? and as so often in Plato it ends up inconclusively (“aporia” to ancient Greeks and modern scholars). Of course much is considered, clarified, and much rejected along the way – presumably valuable steps toward a legitimate answer if one’s possible. Plato, in stark contrast to Aristotle, rarely provides a clear and unambiguous doctrine for acceptance or rejection; whether his own beliefs were as qualified and provisional as the dialogues appear to suggest we’ll never know. But he does seem to have believed pretty firmly that a concept given to a mind rather than discovered by it isn’t of much value, either in itself or perhaps more importantly as a way of developing understanding (i.e. of doing philosophy).

This Hackett edition is a nice translation (I’d found Jowett’s unsatisfactory and Cornford’s good, but the constant interruptions of the running commentary unworkable for a first read). It has a good, brief introduction, a useful outline, and few but helpful footnotes. Hackett’s Plato is pretty reliably high quality (Penguin’s is usually good too, and R. E. Allen has been working for years on commentaries and translations of the dialogues which are excellent: he’s done Parmenides; I hope to see Theaetetus and Sophist by him some day. I haven’t used the couple recent single volume modern translation compilations so I can’t comment on them, but I’d also like to get familiar with those). Well, on to Sophist ….
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Sócrates, a mais ilustre parteira de ideias da Grécia antiga, conduz o mancebo Teeteto ao conhecimento do que o conhecimento não é, pois nem todo filho do conhecimento o é em verdade - e diferentemente dos legisladores, escravos da pressa e do relógio, agressivos por pressão do meio, os filósofos são amantes da verdade, e podem passar em conversa argumentos que por fim mostram-se insuficientes. Seria errôneo, entretanto, dizer que a tarefa foi em vão. E ademais, Sócrates precisa ir a um julgamento se defender...

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O que apreendi: Aamaiêutica mostra que o conhecimento (o "saber que") não é a percepção, pois, modus tolens, com Protágoras, o humano não é a medida de todas as coisas - as coisas não são como aparecem; o vento sendo frio e quente só o é para duas pessoas, uma sem casaco. E com isso, há quem saiba mais e menos, e o julgamento sobre a percepção falha. E ouvir uma fala não é entendê-la, e lembrar algo não é o perceber. Ademais, com Heráclito, se tudo for fluxo, mas como diferenciar então o as aparências verdadeiras das falsas, intersubjetivamente, e dizer de algo algo sem este significado estar em fluxo? Por fim, a existência, igualdade e diferença não operam pelos sentidos.

A maiêutica também mostra que conhecimento não são julgamentos acertados sobre as experiências. A ideia aqui é mostrar como conhecimentos empíricos poderiam surgir das percepções e mostrar a dificuldade em definir crenças falsas a partir daí, que permitiriam determinar quais são as verdadeiras. Um empirista acredita na existência de proposições? Se uma coisa falsa é julgar o que não é, que é presente imediatamente a nós, é julgar nada, que é um nada julgar. E se tudo for imediato, o que será conhecido será identificado, e o que não não. E se imprimirmos crenças como cera, ainda assim o erro entre a impressão e a indicação do que foi impresso, mas e os erros de aritmética? E se tivermos conhecimentos e ignorâncias dentro da mente, ainda assim, como entender como são confundidos? E conhecimento não é crença verdadeira, porque um advogado pode fazer os júris chegarem a tal estado, sem que eles de fato tenham conhecimento sobre a situação.

Mas e se o conhecimento for a crença verdadeira justificada? Justifiquemos com o sonho de Sócrates, a dizer que é preciso analisar as coisas em seus componentes simples. E temos então conhecimento das coisas complexas, porque analisadas e vistas como combinantes das coisas simples que são dadas. Peguemos a sílaba Só de Sócrates, que nos exige saber S e ó (que não são dados!)' também Só não é meramente esses elementos; e nem a sílaba um primário, que se ainda assim fosse, seria dado e não conhecido. Depois, a razão não é nem a fala, nem enumeração (que não diferencia os que só sabem fazer e não sabem como algo é), nem o diferencial, que qualifica, mas não muda as dificuldades quanto ao conhecimento do algo qualificado.

Então, abandonem o empiricismo, oh, epistemologistas. ( )

Extremely complex and difficult to follow, but still worth the read. ( )

(Original Review, 2002-06-25)

I've always wondered whether a thesis can only be supported by reason. Is that self-evident or can we find a reason for it?

Plato actually faces and tries to answer similar challenge in “Theaetetus” when he is discussing the nature of knowledge with Protagoras who is a relativist. Plato offers an argument trying to show that Protagoras claim that knowledge is perception must be wrong and he achieves this by making an argument. So we might reply to your question along similar lines: the sceptic about reason is claiming to have knowledge when he says that people never act for reasons but only because they are moved by rhetoric but knowledge to be knowledge and not mere true belief must involve logos or justification and so the sceptic's view is incoherent. He is arguing that knowledge does and does not involve responding to reasons but that is an incoherent view.

This is roughly how Plato tries to deal with the epistemic relativist and his argument is useful in dealing with modern day relativists like Richard Rorty or the social constructivists like Bruno Latour.
Let’s look at it from Plato's point of view. He will say that knowledge is a normative notion in the sense that it involves justification; knowledge is characterized by Plato as justified, true belief. But that says that reason enters into knowledge via justification and is a necessary condition of knowledge in a sense that if you only possess belief that is true (take a guess and think that I’m are writing on a HP laptop and that happens to be the case; do I know that I’m writing this on a HP laptop ? No, you don’t, even though my belief is true) you don’t have knowledge.

So the claim is pretty strong: it is not just that reason can support knowledge on this Platonic view but rather that it logically has to; reason and knowledge are conceptually tied together Plato wants to argue. This is not just an empirical claim but a conceptual one.

What the sceptic and the post modernists like Rorty are challenging is what might be called the classical picture of knowledge which can be traced to Plato:

(i) The world which we seek to understand and know about is what it is largely independently of us and our beliefs about it;

(ii) Facts of the Form -- information E justifies belief B -- are society-independent facts ,and

(iii) Under the appropriate circumstances, our exposure to the evidence alone is capable of explaining why we believe what we believe.

This is Plato's view and is also embraced by Anglo American philosophy and science. The sophists like Protagoras (and in ethical sphere it's Callicles and Thrasymachus) and post modernists like Heidegger, Rorty, Foucault, Latour and so on and of course people in social sciences and humanities influenced by pomo reject this picture by rejecting either one or all components of the classical picture.

Forms are universals and not directly perceived when I see turds and flies although I can intuit these forms. They constitute metaphysical background of ordinary things and are ontologically necessary to explain first of all why ordinary things like turds are in fact turds and secondly how we can come to know ordinary things. So, forms for Plato are ontologically fundamental and prior to what is given in experience and so on this view it is not something we create. Forms are independent of our perceiving them and can be in intuited and so are turds and flies and so, Plato is a realist.

No , the cave works like this : just as in the cave when I look at the dog's shadow on the wall which is a reflection of the dog but dont actually see the real dog so in the waking experience of the world I see things that are contingent, impermanent and transient . When I see a dog I see the reflection of the dog but not the Form of the universal dog. Roughly, Plato wants to say this because he thinks that ordinary scientific and everyday knowledge is too insecure and too revisable to be certain and to the extent to which Plato wants. His model of knowledge is logic and maths and he has doubts about empirical knowledge ; we have two categories ar two classes of knowledge with maths being the better one . This is not that controversial because Plato is distinguishing analytic a priori knowledge from empirical knowledge , the distinction we continue to make . What is unusual is his denigration of the empirical. ( )