Theaetetus
by Plato
Reading #39 ("Memorabilia 3", 2026)
Abstract
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Bibliographic Data
| Kind | Term |
|---|---|
| authors | Plato |
| literary form | dialogue |
| genres | Socratic dialogue |
| subjects | |
| period | Classical Greece, 5th c. BCE, 4th c. BCE |
| language | Ancient Greek, Attic Greek |
| same as | wikidata | wikipedia |
| keywords & tags | none |
Contextual Relations
Refers To
- (none)
Referenced By
- (none)
Outline (142a–210d)
142a–144e: the frame story
Summary: the dialogue begins with Socrates inquiring upon young Theaetetus as to whether it is the case that they have similar faces, and is preceded by a brief digression whereupon we learn that dialogue is the product of notes written by Euclides, who first heard an account of it from Socrates himself.
142a–143c: the outer frame story
Euclides encounters Terpsion in Megara (142c). The former is just in from Athens (142a) and brings news that Theaetetus’ life is near its end, due to disease while serving Athens in war in Corinth (142a). They lament this unfortunate news, as Theaetetus had conducted himself well in this campaign and is considered a great man in general. This sentiment, it would seem, was anticipated many years ago, by Socrates, just before his death1 when he had the chance to meet Theaetetus, who was then still a young boy (142c).
Euclides recounts that he first heard of their encounter—i.e. between Socrates and young Theaetetus—when Socrates himself told him, excitedly after having first met the young lad. Based on this first hand account, Euclides started keeping some written notes of this story at his home, in Megara, and would ask Socrates for help with any necessary corrections, that he would subsequently make upon his return (143a).
It is these notes that are the basis for the ensuing dialogue, along with some minor but necessary changes when adapting the oral account to a written format, for the sake of brevity (143c). Socrates and Theodorus are speaking when the latter tells the former about a seemingly ideal young boy named Theaetetus.
143c–144e: the inner frame story
Socrates inquires whether Theodorus has met any promising young Athenian boys (143d). Theodorus replies t—hat there’s one in particular, who is not beautiful (143e)—like Socrates—and is blessed with a quick mind, gentle temperament, and is as masculine as any of the other boys (144a). Additionally, he’s of a distinguished father, Euphronius of Sunium (144c), and he appears to be very generous with the small amount of money he was left with, after his trustees “made away” with the rest (144d). At this moment Theaetetus is close by, with his friends, and Socrates asks Theodorus to call him over.
When Theaetetus arrives Socrates claims that he desires to know what kind of face he has2, and thus begins his questioning of the boy with this pretense (144e).
144e–151d: prologue
Summary: in response to hearing that this young boy, Theaetetus, has the same face as him, Socrates seeks the boy’s presence to see for himself. He explains to the boy what he’s heard and in the process manages to cleverly secure both the boy’s agreement to questioning and the topic at hand: what is knowledge? Socrates turns to the metaphor of the midwife in explaining his role as a facilitator of labor for the soul. In the process the nature of the question is further clarified; they seek a single, general answer of what is knowledge.
144e–145b: why Theaetetus should agree to be questioned
Summary: Theaetetus unwittingly agrees to submitting himself for interrogation by Socrates, who jokingly ambushes him by securing his agreement in principle that: A.) one should want to earn the kind of praise that’s directed towards one’s soul and B.) that one can not simply take another’s word for it in this matter.
The chain of questioning is as follows:
Q1: If Socrates and Theaetetus each had some easy way to test something, should they be satisfied to take Theodorus’ word or see if he has some expertise?—They should inquire (144e). E.g. each has a lyre that Theodorus claims are in tune.
Q2: If upon inquiring it is learned that Theodorus is a musician his claim in Q1 should be believed, otherwise it should not?—Yes (144e).
Q3: Then concerning the claim that Socrates and Theaetetus have similar faces, should they inquire if Theodorus has knowledge of drawing?—Yes, one would think (145a).
Q4: And so is Theodorus an artist?—Not as far as one knows (145a).
Q5: Nor is Theodorus a geometer?—He is very much a geometer (145a).
Q6: And is Theodorus not a master of all an educated man should know (e.g. astronomy, arithmetic, and music)?—He seems that way (145a).
Q7: Then on the basis of Q6, should Socrates and Theaetetus listen to Theodorus when he asserts there is some physical resemblance?—Not necessarily (145a).
Q8: However, if Theodorus were to offer praise with respect to the souls of either Socrates or Theaetetus, then should they be eager to win such praise?—Yes, very much indeed (145b).
Conclusion: therefore Theaetetus should be eager now to do precisely that, as Theodorus was just praising him so.
145d–148b: the meaning of the question “What is knowledge?”
- 145d-146b: is knowledge different from wisdom?
- To learn is to become wiser?—Of course
- Wisdom is what makes men wise?—Yes
- Is wisdom then different from knowledge?—They are not
- Socrates is conflicted with this
- 146c–146e: what is knowledge?
- Theaetetus: the kinds of things Theodorus teaches (146c)
- Socrates: those are things one may have knowledge of not what knowledge itself is (146e)
- 147a–147c: knowledge cannot be examples of knowledge
- Can the name of a thing be understood without knowing the thing?—No (147b)
- Therefore if one does not know what knowledge is they cannot know what knowledge of shoes is (i.e. cobbling), and ignorance of knowledge precludes any craft
- 147d–148b: Geometrical digression by Theaetetus exemplifying this concept by giving a general account for what an irrational number is (rather than examples of irrational numbers)
148c–151d: dialectician as midwife
Socrates’ mother, Phaenarete, was a midwife, and he continues to practice the art in secret (149a).
Q: Why is it a secret that Socrates practices the art of midwifery?
Show answer
There are two parts to this answer. First, it would appear it’s a secret in the sense that simply nobody else sees it that way, or it wouldn’t occur to any of them to do so. However, Socrates also asks Theaetetus to keep it a secret.
Q2: Why does Socrates ask Theaetetus to keep this secret?
Show answer
The answer to this is more mysterious than the first, for it can be certain that it’s not for the purpose of actually keeping it a secret, since everything Socrates is doing is very much out in the open, for all who wish to see. Therefore, one can not answer definitively—in a strict sense—one way or another. However, one possibility may be this is just a rhetorical flourish—the verbal equivalent of a wink—or it could also perhaps be that his effectiveness in this art depends in part on it not being characterized in this overt way.
Finally though is the possibility that it is perhaps for Theaetetus’ own benefit that this should remain a secret.
Q3: How could it be for Theaetetus’ benefit to keep this a secret?
Show answer
Although not directly asserted in the text, other works would support that idea that it could even be dangerous for Theaetetus to challenge people’s realities, for example by exposing this secret to them. In the cave allegory (Republic 514a–520a), for instance, the prisoners are more likely to harm the messenger rather than change their mind about there being a world outside the cave. Socrates himself was ultimately tried for confronting certain people (Apology 23e–24a) that were uncomfortable or offended by his way of questioning.
The implication here is that it is important for many reasons—including one’s own safety—to allow others arrive to their own conclusions, and to not disrupt their ignorance antagonistically by rubbing the truth in their faces. However, there is a broader idea at stake here about the role of the dialectical midwife; that gently coaxing the truth from someone is an important part of the job itself, something that perhaps Socrates is grooming young Theaetetus to one day do himself.
However, it is common knowledge that he is strange and causes difficulties for people (149a). In order to explain why he must explain midwifery more generally.
First, the art of midwifery is never practiced by those who are still conceiving and bearing children (149b). This requires some reconciliation with the goddess Artemis, who is the goddess of childbirth.
Mythological digression about Artemis as the deity of midwifery
Socrates accounts for the apparent contradiction between his earlier statement (149b) and Artemis as a virgin and the goddess of childbirth. The explanation is that Artemis made it as such—that midwifes are always women past the age of childbirth—because human nature is too weak to acquire skill—i.e. knowledge of something—without experience. Those who are past child–bearing age are entrusted with this task because they have the benefit of experience.
Q: What is the implication?
Show answer
Experience isn’t necessary to practice an art, but knowledge is. Since human nature is weak, we often can only acquire knowledge through experience—as in the case of midwifes—but there is nothing mandatory about experience. On the other hand, knowledge is very much mandatory, because no craft could be practiced without it, even if one had experience.
Socrates continues that midwives also have certain abilities that come from their knowledge, like how to bring about the (labor) pains, how and when to use certain drugs, the singing of incantations, as well as matchmaking. He notes that this is not the same thing as the illegal act of procuring3 (150c).
Q: If we follow Socrates’ analogy of him as a midwife, then what might procuring and matchmaking be analogous to?
Show answer
If the dialectician is the midwife—and therefore the matchmaker—it seems that the best candidate for the procurer are the sophists. The key differentiator is the involvement of money.
The nature of Socrates’ own form of midwifery
But Socrates contends that his own work is even more important than midwifery (150a), because he watches over the labor of the soul (150b). Aside from this he gives the following differences between the two arts:
- in his work the patient can give birth to either a reality or a delusion (150b), which is