Plato's Theaetetus: what is knowledge?
Plato, Theaetetus (c. 369 BCE), translated by Benjamin Jowett
The dialogue that first asks what knowledge is, and ends by rejecting every answer it tries, including true opinion with an account.
Why it matters
The Theaetetus is the first sustained attempt in Western philosophy to say what knowledge is, and it fails, deliberately. Theaetetus proposes that knowledge is perception, then that it is true opinion, then that it is true opinion combined with an account. Socrates dismantles each, and the dialogue closes with the question still open.
The middle passage is the one I return to most. Socrates points to the courtroom: an orator can bring a jury to a true opinion about something only an eyewitness could know, and the jury, though right, does not know. True opinion is not enough. That is the problem of luck in its first form, and it is the problem a language model poses at scale. A system can bring a user to true opinions about matters it has no relation to except through the text it was trained on. The user is the jury; the model is not the eyewitness.
My own answer to the narrower question, what a source must be like for its word to give knowledge, is the Tracking Minimum: the truth of what is said must figure in why it is said, through the source’s own operation. Theaetetus’ last proposal fails because ‘an account’ can be had without the right connection to the thing. The modern versions of his problem have not gone away; they have acquired servers.
Socrates asks: What is knowledge?
Theaetetus c. 145d–146a
SOCRATES: Yes, my boy, and so do I; and my desire is to learn of him, or of anybody who seems to understand these things. And I get on pretty well in general; but there is a little difficulty which I want you and the company to aid me in investigating. Will you answer me a question: 'Is not learning growing wiser about that which you learn?'
THEAETETUS: Of course.
SOCRATES: And by wisdom the wise are wise?
THEAETETUS: Yes.
SOCRATES: And is that different in any way from knowledge?
THEAETETUS: What?
SOCRATES: Wisdom; are not men wise in that which they know?
THEAETETUS: Certainly they are.
SOCRATES: Then wisdom and knowledge are the same?
THEAETETUS: Yes.
SOCRATES: Herein lies the difficulty which I can never solve to my satisfaction--What is knowledge? Can we answer that question? What say you? which of us will speak first? whoever misses shall sit down, as at a game of ball, and shall be donkey, as the boys say; he who lasts out his competitors in the game without missing, shall be our king, and shall have the right of putting to us any questions which he pleases...Why is there no reply? I hope, Theodorus, that I am not betrayed into rudeness by my love of conversation? I only want to make us talk and be friendly and sociable.
The jury and the eyewitness; true opinion "combined with reason"
Theaetetus c. 201a–d
SOCRATES: The trail soon comes to an end, for a whole profession is against us.
THEAETETUS: How is that, and what profession do you mean?
SOCRATES: The profession of the great wise ones who are called orators and lawyers; for these persuade men by their art and make them think whatever they like, but they do not teach them. Do you imagine that there are any teachers in the world so clever as to be able to convince others of the truth about acts of robbery or violence, of which they were not eye-witnesses, while a little water is flowing in the clepsydra?
THEAETETUS: Certainly not, they can only persuade them.
SOCRATES: And would you not say that persuading them is making them have an opinion?
THEAETETUS: To be sure.
SOCRATES: When, therefore, judges are justly persuaded about matters which you can know only by seeing them, and not in any other way, and when thus judging of them from report they attain a true opinion about them, they judge without knowledge, and yet are rightly persuaded, if they have judged well.
THEAETETUS: Certainly.
SOCRATES: And yet, O my friend, if true opinion in law courts and knowledge are the same, the perfect judge could not have judged rightly without knowledge; and therefore I must infer that they are not the same.
THEAETETUS: That is a distinction, Socrates, which I have heard made by some one else, but I had forgotten it. He said that true opinion, combined with reason, was knowledge, but that the opinion which had no reason was out of the sphere of knowledge; and that things of which there is no rational account are not knowable--such was the singular expression which he used--and that things which have a reason or explanation are knowable.
The closing summary: knowledge is neither sensation nor true opinion nor true opinion with an account
Theaetetus c. 210a–d
SOCRATES: But how utterly foolish, when we are asking what is knowledge, that the reply should only be, right opinion with knowledge of difference or of anything! And so, Theaetetus, knowledge is neither sensation nor true opinion, nor yet definition and explanation accompanying and added to true opinion?
THEAETETUS: I suppose not.
SOCRATES: And are you still in labour and travail, my dear friend, or have you brought all that you have to say about knowledge to the birth?
THEAETETUS: I am sure, Socrates, that you have elicited from me a good deal more than ever was in me.
SOCRATES: And does not my art show that you have brought forth wind, and that the offspring of your brain are not worth bringing up?
THEAETETUS: Very true.
SOCRATES: But if, Theaetetus, you should ever conceive afresh, you will be all the better for the present investigation, and if not, you will be soberer and humbler and gentler to other men, and will be too modest to fancy that you know what you do not know. These are the limits of my art; I can no further go, nor do I know aught of the things which great and famous men know or have known in this or former ages. The office of a midwife I, like my mother, have received from God; she delivered women, I deliver men; but they must be young and noble and fair.
Questions for discussion
- The jury reaches a true verdict without knowing. What does the eyewitness have that the jury lacks?
- Theaetetus' last proposal is that knowledge is true opinion with an account. Why does Socrates think each sense of 'account' fails?
- The dialogue ends without a definition of knowledge. Is an inquiry that ends this way a failure?
The text and its source
- Edition
- The Dialogues of Plato, translated by Benjamin Jowett, as transcribed in Project Gutenberg eBook #1726 (the e-text, produced by Sue Asscher, does not say which of Jowett's editions (1871, 1875 or 1892) it reproduces)
- Source
- Project Gutenberg
- Status
- Public domain: Plato (d. c. 347 BCE); Jowett's translation first published 1871, Jowett died 1893; the Gutenberg e-text is public domain in the US.
- Notes on the text
- Stephanus numbers are not printed in the Gutenberg e-text; the locators give the conventional Stephanus range and are approximate ("c."). Gutenberg renders dashes as "--" in this file; they are kept as in the source. Passage 2 begins a little before 201c so that the jury/eyewitness example (201a–c), which motivates Theaetetus' proposal, is included; the proposal itself is 201c–d. In this translation the proposal reads "true opinion, combined with reason, was knowledge". Passage 3 continues past the summary (210a–b) to the midwife's close (210c–d). The requested sentence "Herein lies the difficulty which I can never solve to my satisfaction—What is knowledge?" appears in the source with "--" for the dash.
Questions it bears on
Terms
Cite this page
Plato. Theaetetus. Translated by Benjamin Jowett. In: Plato's Theaetetus: what is knowledge?, abhinavsaxena.in library. https://abhinavsaxena.in/library/plato-theaetetus/