The phrase "I know that I know nothing" or "I know one thing: that I know nothing", sometimes called the Socratic paradox, is a well-known saying that is derived from Plato's account of the Greek philosopher Socrates. The phrase is not one that Socrates himself is ever recorded as saying, and there is some disagreement about whether it accurately represents a Socratic view.
This saying is also connected or conflated with the answer to a question Socrates (Xenophon) or Chaerephon (Plato) is said to have posed to the Pythia, the oracle of Delphi, in which the Oracle stated something along the lines of Socrates is the wisest.
The phrase, originally from Latin ("ipse se nihil scire id unum sciat"), is a possible paraphrase from a Greek text (see below). It is also quoted as "scio me nihil scire" or "scio me nescire". It was later back-translated to Katharevousa Greek as "[ἓν οἶδα ὅτι] οὐδὲν οἶδα", [èn oîda óti] oudèn oîda).
The saying, though widely attributed to Plato's Socrates in both ancient and modern times, actually occurs nowhere in Plato's works in this form. Two prominent Plato scholars have recently argued that the claim should not be attributed to Plato's Socrates.
Evidence that Socrates does not actually claim to know nothing can be found at Apology 29b-c, where he claims twice to know something. See also Apology 29d, where Socrates indicates that he is so confident in his claim to knowledge at 29b-c that he is willing to die for it.
[…] ἔοικα γοῦν τούτου γε σμικρῷ τινι αὐτῷ τούτῳ σοφώτερος εἶναι, ὅτι ἃ μὴ οἶδα οὐδὲ οἴομαι εἰδέναι.
[Then I have seemed at least than this [person] at any rate with this little something itself to be wiser: because that which I may not have known-through-seeing in no way I imagine myself to have known-through-seeing.]
The impreciseness of the paraphrase of this as I know that I know nothing stems from the fact that Plato's Socrates is not saying that he does not know anything but means instead that he cannot know anything with the absolute certainty of seeing. Socrates feels confident only in his possibly being mistaken about what he has known through seeing given the power of the imagination.
Chaerephon, a friend of Socrates asked Pythia (the oracle of Delphi): "Is anyone wiser than Socrates?" The answer was: "No human is wiser." Socrates, since he denied any knowledge, tried to find someone wiser than himself among politicians, poets, and craftsmen. It appeared that politicians claimed wisdom without knowledge; poets could touch people with their words, but did not know their meaning; and craftsmen could claim knowledge only in specific and narrow fields. The interpretation of the Oracle's answer might be Socrates' awareness of his own ignorance.
καὶ νῦν περὶ ἀρετῆς ὃ ἔστιν ἐγὼ μὲν οὐκ οἶδα, σὺ μέντοι ἴσως πρότερον μὲν ᾔδησθα πρὶν ἐμοῦ ἅψασθαι, νῦν μέντοι ὅμοιος εἶ οὐκ εἰδότι.
[So now I do not know what virtue is; perhaps you knew before you contacted me, but now you are certainly like one who does not know.] (trans. G.M.A. Grube)
Here, Socrates aims at the change of Meno's opinion, who was a firm believer in his own opinion and whose claim to knowledge Socrates had disproved.
It is essentially the question that begins "post-Socratic" Western philosophy. Socrates begins all wisdom with wondering, thus one must begin with admitting one's ignorance. After all, Socrates' dialectic method of teaching was based on that he as a teacher knew nothing, so he would derive knowledge from his students by dialogue.
There is also a passage by Diogenes Laertius in his work Lives and Opinions of Eminent Philosophers where he lists, among the things that Socrates used to say: "εἰδέναι μὲν μηδὲν πλὴν αὐτὸ τοῦτο εἰδέναι", or "that he knew nothing except that he knew that very fact (i.e. that he knew nothing)."
Again, closer to the quote, there's a passage in Plato's Apology, where Socrates says that after discussing with someone he started thinking that
τούτου μὲν τοῦ ἀνθρώπου ἐγὼ σοφώτερός εἰμι· κινδυνεύει μὲν γὰρ ἡμῶν οὐδέτερος οὐδὲν καλὸν κἀγαθὸν εἰδέναι, ἀλλ᾽ οὗτος μὲν οἴεταί τι εἰδέναι οὐκ εἰδώς, ἐγὼ δέ, ὥσπερ οὖν οὐκ οἶδα, οὐδὲ οἴομαι· ἔοικα γοῦν τούτου γε σμικρῷ τινι αὐτῷ τούτῳ σοφώτερος εἶναι, ὅτι ἃ μὴ οἶδα οὐδὲ οἴομαι εἰδέναι.
I am wiser than this man, for neither of us appears to know anything great and good; but he fancies he knows something, although he knows nothing; whereas I, as I do not know anything, so I do not fancy I do. In this trifling particular, then, I appear to be wiser than he, because I do not fancy I know what I do not know.
- H Bowden - Classical Athens and the Delphic Oracle: Divination and Democracy (p.82) Cambridge University Press, 5 May 2005 ISBN 0521823730 [Retrieved 2015-04-22]
- "He himself thinks he knows one thing, that he knows nothing"; Cicero, Academica, Book I, section 1.
- A variant is found in von Kues, De visione Dei, XIII, 146 (Werke, Walter de Gruyter, 1967, p. 312): "...et hoc scio solum, quia scio me nescire [sic]... [I know alone, that (or because) I know, that I do not know]."
- Translatum: The Greek Translation Vortal – Topic: All I know is that I know nothing
- Gail Fine, "Does Socrates Claim to Know that He Knows Nothing?", Oxford Studies in Ancient Philosophy vol. 35 (2008), pp. 49–88.
- Fine argues that "it is better not to attribute it to him" ("Does Socrates Claim to Know that He Knows Nothing?", Oxford Studies in Ancient Philosophy vol. 35 (2008), p. 51). C.C.W. Taylor has argued that the "paradoxical formulation is a clear misreading of Plato" (Socrates, Oxford University Press 1998, p. 46).
- Plato, Apology 21d.
- Plato, Meno 80d1–3.
- Diogenes Laertius II.32.
- Terence Irwin, The Development of Ethics, vol. 1, Oxford University Press 2007, p. 14; Gerasimos Santas, "The Socratic Paradoxes", Philosophical Review 73 (1964), pp. 147–64.