Theaetetus (dialogue)
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The Theaetetus (/ˌθiːɪˈtiːtəs/; Greek: Θεαίτητος Theaítētos, lat. Theaetetus) is a philosophical work written by Plato in the early-middle 4th century BCE that investigates the nature of knowledge, and is considered one of the founding works of epistemology. Like many of Plato's works, the Theaetetus is written in the form of a dialogue, in this case between Socrates and the young mathematician Theaetetus and his teacher Theodorus of Cyrene. In the dialogue, Socrates and Theaetetus attempt to come up with a definition of episteme, or knowledge, and discuss three definitions of knowledge: knowledge as nothing but perception, knowledge as true judgment, and, finally, knowledge as a true judgment with an account. Each of these definitions is shown to be unsatisfactory as the dialogue ends in aporia as Socrates leaves to face a hearing for his trial for impiety.
As one of the major works of Plato's theory of knowledge, the Theaetetus was influential on
Date and setting
The Theaetetus is one of the few works of Plato that gives contextual clues on the timeline of its authorship: The dialogue is framed by a brief scene in which Euclid of Megara and his friend Terpsion witness a wounded Theataetus returning on his way home after from fighting in an Athenian battle at Corinth, from which he apparently died of his wounds. Euclid tells his friend that he has a written record of a dialogue between Socrates and Theaetetus, which occurred when Theaetetus was quite a young man. The dialogue is then read aloud to the two men by a slave owned by Euclid.
The exact timeline of which battle at Corinth has been a matter of some disagreement between scholars: it has generally been presumed that the battle occurred in 369 BC; when Theaetetus would have been in his late forties, but more recently, scholars including Debra Nails have argued that the battle referenced in the dialogue was a different battle in Corinth that occurred much earlier, in 391 BC, when Theatetus would have been in his late 20s.[1]
As far as internal characteristics, the dialogue is considered to be similar to the "earlier" dialogues of Plato, such as the Euthyphro or the Crito, in that Plato's Socrates discusses the nature of knowledge in the Theaetetus without giving any of his own views, and the dialogue ultimately ends in aporia without a satisfying answer. However, it also resembles many of the more philosophically complex "later" dialogues such as Parmenides, Phaedrus and the dialogues Sophist and Statesman which serve as a narrative sequel.
Characters of the dialogue
- Euclid of Megara - the founder of the Megarian school of philosophy, a student of Socrates and contemporary of Plato.[2]
- Terpsion - a friend of Euclid who is unknown outside of this dialogue, although later fables about him, that were likely written on the basis of this dialogue are preserved by Plutarch[3] and in the Cynic epistles.[4]
- Socrates - the famous teacher of Plato, who was executed by the people of Athens in 399 BC. In the dialogue, which takes place just before Socrates visits the Palace of the King Archon for his Trial of Socrates, Socrates is an old man of about 70.
- Theodorus - a Greek mathematician from Cyrene, a prosperous Greek colony on the coast of North Africa, in what is now Libya, on the eastern end of the Gulf of Sidra. Theodorus explored the theory of incommensurable quantities, and according to Diogenes Laertius, was said to have taught mathematics to Plato, although the historicity of this claim cannot be verified.[5]
- Theaetetus - A Greek mathematician from Athens, who is credited in Book X of Euclid's Elements with developing a method for measuring irrational lengths in terms of square roots, as well as the proof that there are precisely five regular convex polyhedra.[6] According to the dialogue, he evidently resembled Socrates in the snubness of his nose and bulging of his eyes. He apparently died from wounds and dysentery after the battle in Corinth that occurs in the frame story of the dialogue.
Socrates, Theaetetus, and Theodorus reappear the following day in the Sophist an apparent continuation of the conversation contained within the book of Euclid, where they are also joined by an unnamed
Outline
The narrative of the dialogue is set in a
Socrates tells Theaetetus that he cannot make out what knowledge is, and is looking for a simple formula for it. Theaetetus says he really has no idea how to answer the question, and Socrates tells him that he is there to help. Socrates says he has modelled his career after his
Protagoras' theory of knowledge
Socrates thinks that the idea that knowledge is perception must be identical in meaning, if not in actual words, to Protagoras' famous maxim "Man is the measure of all things."
Socrates wrestles to conflate the two ideas, and stirs in for good measure a claim about
Socrates then proceeds to explain why philosophers seem clumsy and stupid to the common lot of humanity. Socrates explains that philosophers are open to mockery because they are not concerned about what interests most people: they could not care less about the scandals in their neighbor's house, the tracing of one's ancestry to Heracles, and so on. In contrast, the philosopher is concerned with things that are, such as beauty and knowledge, which are "truly higher up". It is here that Socrates draws the classic portrait of the absent-minded intellectual who cannot make his bed or cook a meal (175e). Socrates adds a big bifurcation to this speech, saying that there are only two kinds of lives to be lived: a divinely happy one, lived by righteous philosophers or a godless, miserable one, such as most people live.[g] Socrates admits this was a digression that threatens to drown his original project, which was to define knowledge. Theodorus, the old geometer, tells Socrates that he finds this sort of thing easier to follow than his earlier arguments. Socrates says that the men of flux, like Homer and Heraclitus, are really hard to talk to because you can't pin them down. When you ask them a question, he says, they pluck from their quiver a little aphorism to let fly at you, and as you try to figure that one out, they wing another one at you. They leave nothing settled either in discourse, or in their own minds. Socrates adds that the opposite school of thought, that teaches of the "immovable whole" is just as hard to talk to.[h] Socrates says he met the father of the idea, Parmenides, when he was quite young, but does not want to get into another digression over it.[i]
Definitions of knowledge
Socrates compares the human
Socrates responds by telling of a dream, in which he overheard people talking of primary elements.[r] These primary elements can only be named, they cannot be thought of as existing or not - he gives examples of words like 'itself, or that, each, alone or this.'[s] While they can be added to other words, they by themselves are just a name. When these elements are added together, Socrates says that a 'complex' is formed.[t] The primary elements are 'unaccountable and unknowable, but perceivable' while the complexes are 'knowable and expressible' and so can be objects of 'true judgement'.[u] He concludes his dream by agreeing with Theaetetus that knowledge is 'true judgement with an account.'[v] However, Socrates exposes some difficulties by examining letters. He takes the first two letters of his name, S and O to wonder if the syllable 'So' is knowable while the individual letters are not.[w] Theaetetus finds the idea strange, so Socrates deduces that in order to know the syllable, the letters must be known first.[x] Socrates proposes that the syllable can be a 'single form' produced from the letters. With this in mind, Socrates considers whether the 'sum' and the 'whole' are the same.[y] Theaetetus initially says they are not, but changes his mind in confusion when Socrates leads him through maths and the different ways of expressing the number six.[z] After agreeing this, Socrates returns to the subject of syllables and letters to conclude from Theaetetus' answers that syllables are different from letters and cannot contain letters.[aa] Theaetetus admits this idea is ridiculous.[ab] Socrates returns to talking about elements and complexes to propose that they are in the same class, as they have 'no parts and [are] a single form.'[ac] Socrates sums up this reversal by remarking that if anyone tries to tell them the complex is knowable and expressable while the element is the opposite, 'we had better not listen to him'.[ad] He cites the example of a musician distinguishing individual notes (conceded to be elements of music) to propose that elements are 'much more clearly known.'[ae] Socrates proposes an account to be 'making one's thought apparent vocally by means of words and verbal expressions.'[af] However, he wonders if that is so, everyone will be able to make judgement 'with an account' as they can all (except for the deaf and dumb) vocalize and express opinions on matters.[ag] Socrates examines it further by suggesting that a man who can vocalize his judgement must be able to make reference to the primary elements of the subject.[ah] Giving an example of defining a wagon by its individual parts,[ai], agreement is reached that an account is 'going through a thing element by element.'[aj] Socrates questions Theaetetus by drawing on his learning of how to write, and the idea that if you misplace individual elements (letters) of a name, that does not mean you have knowledge of it.[ak] This finishes Socrates' second definition of an account as 'the way to the whole through the elements' [al].
The third definition Socrates offers is 'being able to tell some mark by which the object you are asked about differs from all other things' [am], giving the example that the Sun is distinct for its brightness. However, this definition of an account fails as by getting to know the differentness of an object, you have to acquire knowledge about it. Thus the answer to the initial question 'What is knowledge' would be heavily circuitous - correct judgement accompanied by 'knowledge' of the differentness, which Socrates admits is 'silly' [an].
Socrates concludes the dialogue by announcing that all the two have produced are mere "wind-eggs" and that he must be getting on now to the courthouse to face his trial being brought against him by Meletus.
Significant references in the dialogue
In this dialogue, Socrates refers to Epicharmus of Kos as "the prince of Comedy" and Homer as "the prince of Tragedy", and both as "great masters of either kind of poetry".[note 1] This is significant because it is one of the very few extant references in greater antiquity (Fourth century BCE) to Epicharmus and his work. Another reference is in Plato's Gorgias dialogue.
The dialogue references the Trial of Socrates, which takes place in 399 BCE and is set right. At the end of the dialogue, as Socrates is leaving to face a hearing at the Porch of the King Archon, he agrees to meet Theaetetus and Theodorus in the same place the following day, a conversation that is recounted in the Sophist and Statesman dialogues. The dialogue Euthyphro also is set on the same day, and would have occurred immediately after the Theaetetus, as it occurs outside the Porch of the King Archon as Socrates awaits his hearing.
The dialogue includes the earliest reference to
Legacy
Later Platonism
The Theaetetus was a popular dialogue in
In
Gettier problems
In the 20th century, the dialogue and its definition of knowledge as a "
Texts and translations
The Theaetetus has been translated into English along with the rest of the Works of Plato
- Plato's Theaetetus translated by Benjamin Jowett (Internet Archive, 1892, text page 193)
- Plato: Theaetetus, Sophist. Greek with translation by Harold N. Fowler. Loeb Classical Library 123. Harvard Univ. Press (originally published 1921).
- The full text is available from the Perseus Project in both Greek and English (Fowler translation).
- Plato. Opera, volume I. Oxford Classical Texts. ISBN 978-0198145691
- Plato. Complete Works. Hackett, 1997. ISBN 978-0872203495
Notes
Footnotes
- ^ "Summon the great masters of either kind of poetry- Epicharmus, the prince of Comedy, and Homer of Tragedy", Theaetetus, by Plato, section §152e[11] (translation by Benjamin Jowett[12]). There is some variability in translation of the passage. Words like "king", "chief", "leader", "master" are used in the place of "prince" in different translations. The basic Greek word in Plato is ἄκροι akroi from ἄκρος akros meaning topmost or high up. In this context it means "of a degree highest of its kind" or "consummate" (cf. Liddell & Scott, A Greek–English Lexicon).[13]
Stephanus numbers
As is standard for the works of Plato, reference numbers are to the page numbers of the 1572 edition of Henri Estienne (Stephanus). Quotations are to the edition by Benjamin Jowett, which is freely available and in the public domain.
- ^ 155c
- ^ 164e
- ^ 166a–168c
- ^ 168d
- ^ 170c
- ^ 171a
- ^ 176–177
- ^ 181a,b
- ^ 184a
- ^ 199a
- ^ 199b
- ^ 200e
- ^ 200e
- ^ 201a
- ^ 201b
- ^ 201c
- ^ 201d
- ^ 201e
- ^ 202a
- ^ 202b
- ^ 202b
- ^ 202c
- ^ 203b–d
- ^ 203e
- ^ 204a
- ^ 204c–205b
- ^ 205b
- ^ 205c
- ^ 205d
- ^ 205e
- ^ 206b
- ^ 206d
- ^ 206e
- ^ 207a
- ^ 207a
- ^ 207d
- ^ 208a
- ^ 208c
- ^ 208c
- ^ 210a
- ^ 176b
Citations
- ^ Debra Nails, The People of Plato. Indianapolis: Hackett Publishing, 2002; pp. 275–278
- ^ Nails 2002, pp. 144–145.
- ^ Plutarch, de Gen. Socr.
- ^ Nails 2002, pp. 274.
- ^ Nails 2002, pp. 281–282.
- ^ Greek Geometry from Thales to Euclid by George Johnston Allman (Hodges, Figgis, & Company, 1889, p. 206).
- ^ a b Dillon 1996, p. 122-123.
- ^ Dillon 1996, p. 270-271.
- ^ Dillon 1996, p. 275.
- ^ Zalta, Edward N. (ed.). "Iamblichus". Stanford Encyclopedia of Philosophy.
- ^ Theaetetus, by Plato, section §152e.
- ^ Theaetetus, by Plato, section §152e, translation by Benjamin Jowett
- ^ "ἄκρος" entry in Liddell & Scott, A Greek–English Lexicon
References
- Dillon, John M. (1996). The Middle Platonists, 80 B.C. to A.D. 220. Cornell University Press. ISBN 978-0-8014-8316-5. Retrieved 22 February 2023.
- Nails, Debra (15 November 2002). The People of Plato: A Prosopography of Plato and Other Socratics. Hackett Publishing. ISBN 978-1-60384-027-9. Retrieved 22 February 2023.
- Allen, R. E. (ed.), 1965, Studies in Plato’s Metaphysics, London: Routledge.
- Anonymous Commentator (“Anon”), 1905, Commentary on Plato’s Theaetetus, Diels and Schubart (eds.), Berlin: Berliner Klassikertexte II.
- Benardete, S., Commentary to Plato's Theaetetus. Chicago: University of Chicago Press, 1984.
- Bostock, D., 1988, Plato’s Theaetetus, Oxford: Oxford University Press.
- Burnyeat, M.F., 1990, The Theaetetus of Plato, with a translation by Jane Levett, Hackett: Indianapolis.
- Chappell, T.D.J., 2005, Reading Plato’s Theaetetus, Indianapolis: Hackett.
- Cornford, F.M., 1935, Plato’s Theory of Knowledge, London: Routledge.
- Denyer, N., 1991, Language, Thought and Falsehood in Ancient Greek Philosophy, London: Routledge.
- Desjardins, Rosemary, The Rational Enterprise: Logos in Plato's Theaetetus, SUNY, 1990.
- Klein, Jacob, Plato's Trilogy: Theaetetus, The Sophist and the Statesman. University of Chicago Press, 1977.
- McDowell, J., 1973, Plato’s Theaetetus, Oxford: The Clarendon Plato Series.
- Robinson, R., 1950, “Forms and error in Plato’s Theaetetus,” Philosophical Review, 59: 3–30.
- Ross, W.D., 1953, Plato’s Theory of Ideas, Oxford: Oxford University Press.
- Runciman, W., 1962, Plato’s Later Epistemology, Cambridge: Cambridge University Press.
- Sayre, K., 1969, Plato’s Analytic Method, Chicago: University of Chicago Press.
- –––, 1983, Plato’s Late Ontology, Princeton: Princeton University Press.
- Sedley, D., 2004, The Midwife of Platonism, Oxford: Oxford University Press.
- White, N.P., 1976, Plato on Knowledge and Reality, Indianapolis: Hackett.
External links
- Works related to Theaetetus at Wikisource
- Theaetetus, in a collection of Plato's Dialogues at Standard Ebooks
- Theaetetus public domain audiobook at LibriVox
- Chappell, Timothy. "Plato on Knowledge in the Theaetetus". In Zalta, Edward N. (ed.). Stanford Encyclopedia of Philosophy.
- Giannopoulou, Zina. "Plato's Theaetetus". Internet Encyclopedia of Philosophy.
- Cornford, F. M., Plato's Theory of Knowledge at googlebooks
- A discussion of Theaetetus' contributions to Euclid's Elements