13 The Theaetetus

Plato could not have been younger than sixty when he wrote the Theaetetus for Theaetetus’s death is the occasion of the dialogue and Theaetetus died in Athens’ war with Corinth in 369.^[1] The richness of the drama and the subtlety of the art show that even at a mature age Plato practiced his familiar methods.

Euclides and Terpsion meet. discuss the sad news about Theaetetus. and reminisce on his especially fine character. When Theaetetus was very young and shortly before Socrates· death. Euclides says. the philosopher had predicted a great future for him (142C). Terpsion is eager to hear the conversation that took place between them. and luckily Euclides has kept it in written form. in a version he checked with Socrates himself several times. That Socrates· conversation would be a matter of interest thirty years after Socrates· death is very curious: what can they have talked about that makes the conversation so memorable? When we consider that Euclides and Terpsion are Megarians. not Athenians. and that there was in Megara a school of Parmenidean dialectics. we see that interest in philosophy and in Socrates continues—even if not in Athens.^[2]

We have observed earlier the dramatic effect of Plato’s reminding us of Socrates’ trial and death. In the Theaetetus we have many reminders of Socrates’ fate. from allusions to the behavior of a philosopher in a courtroom to the explicit statement at the end that Socrates must go to answer the indictment against him. We must reflect how Socrates’ and Theaetetus’s deaths fit into the drama of this play. Had Plato wanted. he could surely have placed the conversation in some happier setting. say. an ordinary meeting at Theodorus’s school. That he expressly calls our attention to the two violent deaths ought to be significant.^[3]

The last event of the outer frame is Euclides’ explanation of his book’s composition. He has omitted narrative explanations such as “he said” and so on and has simply presented the speech. Plato has done the same thing with his framing device. Some have understood this as Plato’s farewell to the more elaborate system of other dialogues and as a change to a deemphasis on drama, but the conclusion does not appear valid.^[4] Such “early” dialogues as the Laches used the technique of direct speakers; what seems more likely is that where the setting is important to his dramatic point, Plato describes it in detail; where is isn’t important, he doesn’t. Surely there is plenty of drama in this dialogue and a great many digressions from what might be called “pure” philosophy—though perhaps “lifeless” would be a more apt description of such works than “pure.”

Euclides tells his slave to take the book and read. Here, I think, we find evidence for the way in which the dialogues must generally have been performed.^[5] A slave read the manuscript to a group of people: Plato’s audience did not sit down with learned commentaries and reflect laboriously about every possible fallacy or respond to a dialogue in the manner of later critics; rather it probably elicited a response akin to that a contemporary audience gives a movie. Unless we are students of the cinema and can look repeatedly at various frames frozen still, we must be content with the general effect that the movie makes. It is entirely possible, however, that a slave might have been asked to repeat a page or two, though it is not likely that in social settings where there were numerous listeners many would have re­ quested such interruptions.

The reported dialogue begins with Socrates asking Theodorus not about the affairs of Cyrene, Theodorus’s home, but of any young men, especially Athenian young men, who devote themselves to geometry and show particular promise (143D). Here we see Socrates’ interest in the youth of his own city, a sign of that love for Athens that figures so prominently in the Apology and Crito. We see as well that as always Socrates is on the lookout for good minds. Theodorus immediately mentions Theaetetus, a young man who is not handsome and in fact resembles Socrates in being snub-nosed and prominent-eyed. But he is quick, gentle, and virile, and, unlike others with such qualities, is enthusiastic and moderate. Praise is added indirectly when Theodorus is unable to remember the name of Theaetetus’s father, for this forgetfulness shows that Theodorus’ s good opinion is not influenced by pedigree, just as it hadn’t been by appearance (for Theaetetus is quite plain). That famous progenitors are no sign of particular excellence is a point Socrates will bring up later. We observe as well that Plato goes to lengths to establish a similarity between Theaetetus and Socrates: not only are they linked in death, but they share the same plain physical features; we the audience shall begin to wonder why Plato emphasizes these similarities.

Finally meeting the young Theaetetus, Socrates remarks on their similar physical appearance, as Theodorus has done. What strikes one immediately about Theaetetus is his modesty. The reader familiar with other dialogues thinks at once of the innumerable characters Socrates has spoken with, youths like Ion or Euthyphro or Meno, puffed up with their own importance and wisdom, in -which they somehow manage to preserve confidence even when proposition after proposition of theirs proves to be erroneous. Theaetetus in sharp contrast responds to Theodorus’s praise by raising the possibility that Theodorus’s compliment was a joke (145C) and by modestly saying that he does his best to learn about geometry and harmonics. Socrates responds that even if Theodorus did not tell the truth, no one will indict him for perjury (145C). Apparently trials and indictments are very much on Socrates’ mind, and references to them constitute one of the motifs of the dialogue. Theaetetus’s self-effacement and persistent refusal to indulge in egotistical boasts is a second motif.

When Socrates brings up the subject he wishes to discuss—the nature of knowledge—everyone becomes silent. Socrates asks whether his zeal for argument has made him ill-mannered. Why, we ask, do the others respond coldly to this topic? Can it be that it is the sort of question no one wants to discuss? This is the only silence in the dialogue. Silence in Plato generally occurs when a boastful interlocutor has been driven into perplexity and no longer wishes or is no longer able to struggle with the topic and withdraws into silence.^[6] Here, at the beginning of the conversation, even before anyone has reached aporia, there is silence. Perhaps the silence is an expression of the awesomeness of the question or of the others’ prior experience struggling with it. The nature of knowledge, after all, does go to the root of education and of the human experience.

Yet there is an apparent strangeness, I think, in Socrates’ bringing up the question of knowledge. In other dialogues there is usually a relation between the dramatic situation and the topic of discussion. For example, in the Laches there is a discussion of courage after an exhibition of fencing; in the Lysis there is a discussion of friendship when two boys claim to know that they are friends. Here the scene is a school, and Theodorus is a teacher of geometry. Theaetetus himself achieved fame later for his brilliant contributions to solid geometry. We might have expected some topic dealing with mathematics; instead we have a discussion of the nature of knowledge. Perhaps Plato is suggesting how close mathematics, and particularly geometry, is to philosophy. He is reputed to have had, after all, two entrance require­ments to the Academy: a good memory and a knowledge of geometry.^[7] Perhaps in Plato’s time, like today, people felt that mathematics was the one subject concerning which humans actually could have knowl­edge—all other subjects being too relativistic or imprecise. Hence, if anyone could define knowledge, it would be mathematicians, and a discussion with them on the topic would be fruitful. Since the setting is a school of mathematics, the nature of knowledge would perhaps not be so unusual a subject after all (though one wonders how often the nature of knowledge was—or is—discussed in schools.)

Theodorus, claiming that the topic is too abstract for him, urges Socrates to press his questions on Theaetetus (146B). On the one hand, when we learn of the close friendship between Theodorus and Prota­goras (162A), Theodorus’s unwillingness to participate in the refutation of his friend is not surprising. On the other hand, Theodorus’s with­drawal from the conversation may be also an expression of self­-knowledge. How much better to admit that you don’t know something than to be exposed as ignorant after a claim of knowledge!

Theaetetus agrees to answer in Theodorus’s stead, modestly asking Socrates to correct him if he errs. Like a great many interlocutors, Theaetetus begins by confusing examples with definitions. But Theae­tetus is not like the others; when Socrates uses the homely example of cobblers and clay, Theaetetus shows his instant grasp of the point by reviewing a discussion of arithmetical roots that he has just had with Theodorus. Socrates approves: there will be no prosecuting Theodorus for perjury (148B). When Socrates asks him for the same kind of sophisticated definition of knowledge, Theaetetus admits that he can­ not give such a definition (148B); thus, he adds, Theodorus’s praise must have been false. When Socrates urges him to try, Theaetetus answers most enthusiastically that if the solution to the problem depends on his zeal, they’ll find the answer. But he assures Socrates that he has often thought about the matter, has always been unable to come up with a solution, and, moreover, has never heard a proper answer. So we discover that Theaetetus’s similarity to Socrates extends beyond mere physical resemblance to intellectual understanding. Both apparently have a sense of ‘truth and humbug and neither is ashamed to admit that he has never heard the truth on a topic.

Theodorus may be Theaetetus’s teacher, but in Socrates Theaetetus has found a kindred spirit. There now follows one of the most sustained similes in all the Platonic corpus:^[8] Socrates compares himself to a midwife who, though past child-bearing herself and barren, is able to help others give birth. Like a midwife, he is also clever at matchmaking. But, says Socrates, he is better than a regular midwife, for he can bring to birth real or phantom children and his midwifery results in the birth not of the body but of the soul, for the children he brings forth are ideas. Some whom he has helped were not aware of his help and left too early and later suffered miscarriages; he gives as an example of such Aristides, son of Lysimachus, whom we recall from the Laches. (One may perhaps wonder why Socrates doesn’t mention Alcibiades. Can it be that Plato did not want to besmirch the dialogue, a memorial to both Socrates and Theaetetus, with that foul name?) When, continues Socrates, he encounters some who show no promise at all and are incapable of conceiving any ideas, why, for these he finds a match—Prodicus! Here again we see this name, so often ironically praised in the corpus that many think Socrates held him in great admiration. How they forget the ridiculous manner in which he appears in the Protagoras. Socrates now proposes to be Theaetetus’s midwife and to try to help deliver an idea from him.

The image is remarkable for several reasons. In contrast to the beauty implicit in the idea of the dialectician as a midwife, we also find some criticism of Socrates—constructive, not damning criticism, but criticism all the same. Midwives, says Socrates (149B-C), can bring on labor or postpone it at will, make a difficult labor easy, and cause an early miscarriage if they so decide . Applying the simile to Socrates, we need to ask whether Socrates does these things: does he deliberately postpone labor? Does he deliberately cause miscarriages? Have we here a suggestion by Plato that Socrates manipulates his conversations? Surely in the present conversation with Theaetetus, it is Socrates who conceives the topic, Socrates who nourishes all the arguments, and Socrates who causes them all to abort. Is there a criticism in the metaphor as perhaps there was in the Daedalus-image in the Euthyphro, where Socrates compared himself to the great sculptor who could make statues, as Socrates can make arguments, move? Don’t both similes point to the philosopher’s manipulative skills?

Theaetetus’s first definition is that knowledge is perception (151E). This notion, says Socrates, belongs to Protagoras, though Protagoras stated it somewhat differently when he declared that man is the measure of all things. Socrates explains the view and equates Protagorean relativism with Heraclitean flux. He invokes Homer and the other poets, except Parmenides, as agreeing in universal motion (152E). Socrates then uses Protagorean sophistry to explain the position, comparing the workings of the human body to the basic principles of the cosmos: as the healthy body needs exercise (153B) but is weakened by inactivity, so is the soul. Of course the argument omits completely the fact that for health the body also requires rest, but it is characteristic of sophistry to omit points that don’t support the argument, and here Socrates sophistically makes the case for relativism.

Socrates suddenly asks whether something may become larger other than by being increased (154C). But it has already been shown that relative terms applied to things may change without the things them­ selves changing. For example, a small man may be larger than a child, and though we may just now have applied the adjective “larger” to him, whereas we had earlier referred to him as “small,” he has not actually undergone any absolute increase. Theaetetus, aware of this equivocal kind of question, replies that he thinks a thing can become large only by an increase but, on guard against contradicting himself, says he will answer otherwise. Socrates appositely quotes from Eurip­ ides’ Hippolytus the title character’s notorious line about the tongue and the heart not having the same meaning—the quintessential sophis­tic statement. He then enjoins Theaetetus not to be sophistic but to say what he really means. Yet Socrates himself continues sophistic Protagorean equivocations until Theaetetus exclaims that he has be­ come dizzy (155C). Socrates takes the dizziness as a sign that Theae­tetus is truly a philosopher, for philosophy begins in wonder. Then, when Theaetetus modestly admits that he doesn’t see where the argument is going, Socrates offers to clarify Protagoras’s views.

Socrates describes the views of those who hold everything to be in flux, who think nothing real except what is tangible (155E-157C).^[9] Socrates is quite convincing, and Theaetetus is unsure whether the views are Socrates’ own. Socrates declines to say, wishing to test Theaetetus’s views (157C-D). Just when Theaetetus says that he finds the views plausible, Socrates springs his trap and casts doubts on the reality of all perceptions (157D-158A). This pattern of Socrates’ leading Theaetetus to a conclusion and then casting doubt upon that very conclusion recurs like a chorus over and over again in the dialogue. As Plato’s audience, we find ourselves saying, “Here we go again,” for every time Theaetetus and we are convinced that we are about to reach a solid conclusion, Socrates brings up some point to throw the whole business into doubt. We find ourselves in the exact same position as Theaetetus, no doubt just where Plato wanted us to be.

Theaetetus realizes immediately that it is not easy to tell whether we are asleep or awake and with characteristic modesty admits that he has no solution to the dilemma. He agrees with Socrates that the length of time spent asleep or awake can’t determine which is the truth (158B­ C).

A rather lengthy argument follows on the infallibility of perceptions (158E-160E). The conclusion seems to be that if one has a perception it must be a perception of something, and for the moment of perception the perception is true for the perceiver; thus knowledge is perception. Though the argument may strike the reader as having its difficulties, Theaetetus affirms that the argument is his “newborn child,” which Socrates has delivered. Theodorus is not convinced, however, and asks Socrates to explain what is wrong with the conclusion. Socrates says that Theodorus must think Socrates a bag of arguments who can easily prove the conclusion wrong. He repeats his claim that the arguments come from others. How can Plato’s audience take Socrates seriously here? After all, no one but Socrates has brought up the various arguments and when he has seemed to reach a conclusion with them, it was he who raised the doubts and began the refutation; he has in short given birth and destroyed his own offspring.

Socrates jokes about Protagoras’s treatise Truth, wondering why the sophist did not make a baboon or a pig the measure of all things.^[10] Such a defiant declaration would surely have expressed the sophist’s disdain for the absoluteness of wisdom. Socrates continues (162D), if each man is the judge of truth, how can Protagoras be wiser than anybody else, and how can he justify his fee for teaching? Socrates adds that his own job of testing opinions would be folly if all opinions were equally true. Theodorus again refuses to argue, claiming that Protagoras is his friend, so Theaetetus takes up the argument once more.

Socrates asks Theaetetus whether or not he is surprised at the turn the argument has taken and to find out that he is as wise as anyone else, man or god. Theaetetus acknowledges that he is surprised, that the conclusion had seemed to him correct but now is thrown into doubt. Socrates claims that the difficulty arises because Theaetetus is so young. What an enchanting exchange! Theaetetus has confessed his intellectual fickleness, and Socrates has attributed it to youth. We the audience of the dialogue will have to admit that we too have been convinced while the argument was going on; we too have seen our heads spinning as one conclusion after another has been overthrown. Are we to attribute our own fickleness to youth? Or perhaps we are meant to see how seductive arguments are and how easy it is to fall into error. Later on the arguments will seem to point out that error is logically impossible. But the drama will undercut those arguments as we recall the numerous errors into which we have fallen. Mere plausi­bility is not enough, Socrates tells Theaetetus, and Theaetetus agrees (162E). Of course, the question is how to go beyond plausibility to truth.

Socrates takes a couple of arguments out of his bag to show that knowledge is not perception: that we can hear a foreign language without knowing what it means; that someone may know something that he remembers and is not currently perceiving (163B-164B). And just when Theaetetus has agreed that knowledge is not perception, Socrates again springs a trap. We have been behaving like verbal sophists, he says, and have allowed verbal consistencies and tricks to get the better of us. To give an example of the kind of trickery he has in mind, Socrates says that “see” and “know” do not mean the same thing since one can see and not see at the same time (when one eye is open and the other closed) but one cannot know and not know at the same time (165B-E). Of course, it is only in an equivocal sense that one is “not seeing” when one eye is closed. Socrates here exploits the power of equivocation, no doubt to remind us of the way Protagoras argues. As Socrates says (165A), strange conclusions are possible if one is careless in the use of language. The dialogue seems more concerned with proper methods of argumentation and pedagogy than it is with the definition of knowledge.

Socrates begins an imaginative defense of Protagoras, conjuring up the sophist to defend his position. The imaginary sophist criticizes Socrates for not giving the arguments that he would make if he were there, but weaker arguments—a defense against which it is impossible to argue since Protagoras is dead. (One could ask the same of the dead Socrates: how would he handle himself if he were saying his own words, not those Plato attributes to him?) A wise man, says the imaginary Protagoras (166D), is one who can persuade others to his view. Some thoughts might be better (167A-C), but that they are “better” does not mean they are truer. Whatever appears sound is sound so long as it appears sound. Finally, he says, Socrates should observe the distinction between a debate, where it is perfectly fine to trip the opponent up, and a conversation, where, since the participants are seeking truth, it is not right to engage in verbal trickery. If such trickery is practiced, it will cause the interlocutor to hate philosophy (167E- l68C).

Socrates uses the imaginary speech to trick Theodorus into arguing with him. Perhaps by engaging with the older Theodorus he can refute the charge that Callicles had made against him, that he talks only with children. Theodorus finally agrees to argue, calling Socrates a Sciron and an Antaeus. Socrates claims to be stronger than both in his powers of endurance, for though his head has been bashed by many a Hera­cles, he still wrestles. Theodorus feels that there is no escape and, calling Socrates Fate, submits.

The general result of the argument with Theodorus is to show clearly the contradiction inherent in the relativist position: if a man is the measure of all things but not all agree with Protagoras’s doctrines, Protagoras must admit that those who disagree are as right as he (169D-172A). Socrates’ refutation depends to a large degree on the absence of the indefinite article in Greek. “Man in general” and “a man” are expressed in the same way. Where Protagoras meant “man in general” Socrates understands “a man.”

Another problem with the Protagorean theory arises, says Socrates, when one discusses religion. While in matters of what is actually good for the state, people may be ready to admit that one adviser may be wiser than another (172B); in matters of good and bad and of religion, they claim that there is no external objective reality.

But before Socrates discusses this, he enters into a long digression about philosophers in a court of law. Theodorus agrees to the digres­sion, saying that they have lots of time. What dramatic irony! Poor Socrates is on his way to the courthouse to answer the indictment against him and to be put on trial for his life. Undoubtedly the very mention of religion made Socrates think about the indictment against him on charges of impiety, and this led to his portrayal of the philosopher in court. The philosopher, he says, requires leisure to pursue an argument and is fitted for going from one argument to another. An orator or a lawyer, on the other hand (172D-173B), is clever at speaking by the clock and at flattering the judges. A slave to the clock, he has no soundness in him. The philosopher is useless in the assemblies. In a sense, only his body is in the city; his soul is elsewhere. He is like Thales, who fell in the well from looking at the stars: in examining the truly important matters, the philosopher fails to look after his own good (174A-B). He doesn’t know what his neighbor is doing because he spends his time asking about man in general. The philosopher appears foolish in court where people laugh at him; he can’t hope to engage in exchanges of abuse. He reacts with genuine laughter to those who vaunt their own baseless merits as if they were kings, for he knows the nature of true kingship. He knows that pride of ancestry and of other worldly matters is of no real value. But in discussing ideas seriously without quoting poetry, the philosopher shines (175C-D).

If only Socrates could convince everyone, Theodorus laments, there would be fewer evils in the world. The remark is, of course, pathetic, for Socrates will soon fail to convince even his fellow Athenians. Plato’s irony reminds us of how much evil there still is in the world and of how much need there is for philosophers instead of orators.

Evils will always be in this world, says Socrates, but not in the divine world.^[11] True wisdom is to become as divine as possible, and there is nothing but righteousness in divinity. An evil man, fancying himself good, does not realize that he cannot escape the punishment of his evil—the state of being evil itself. Such people, if you argue with them and they don’t run away, find their own arguments unsatisfying (176E-177B). But it is time to end the digression, Socrates concludes.

The unusually lengthy digression is, of course, prophetic. Rich in dramatic irony, it reminds all in Plato’s audience of Socrates’ situation. The little time left for Socrates will not be enough to find out what knowledge is; how much less sufficient will the time be when Socrates must speak before a throng of unphilosophical jurors!

We might ask why Socrates has engaged in the digression at exactly this point. Protagoras’s extreme relativism has led to the possibility that neither any mortals nor any gods are wiser than any others. No doubt the mention of the gods has caused Socrates to think of the accusation against him. If Protagoras is right that one’s man opinion is as valid or as false as anyone else’s, there is no point to the charges against Socrates. After all, on what basis could one protest any man’s god as worse than another’s? On the other hand, if Protagoras is wrong, then doesn’t Protagoras represent the real impiety, since his view would reduce gods and mortals to the same level? Socrates’ piety has led him to declare that the job of men is to become like the gods; knowledge of this he calls true wisdom (176C). Such a view would be meaningless in the Protagorean system.

Theodorus responds to the departure from the argument by saying that he prefers the digressions to the arguments, for they are easier to follow (177C). How Plato’s audience must agree! In fact, when one has put aside the Theaetetus, one remembers that the dialectic was incon­clusive; what one retains far longer in one’s memory is the substance of the digressions. Plato clearly knows this and goes so far as to have Theodorus say it outright. Surely he wants us to see Socrates arguing as usual, this time with a first-rate student, the audience fully aware that Socrates will soon die and argue no longer. Perhaps Plato wants us to reflect on how much progress could be made if only this sort of conversation could be carried on longer and more systematically. Though Socrates’ execution left Athens in philosophical perplexity, he seems to be saying, the existence of the Academy mitigates the loss, for such conversations would go on there.

The argument resumes as Socrates shows Theodorus that states do err about what is advantageous to them—thus there must be a standard of the advantageous external to opinions (l 77C- l 78A). Moreover, deliberations in a state concern what will be best for the future, and the one who is best at judging in any particular matter concerning the future is the one skilled in that subject matter. The physician is best at telling about the future of health or disease, a cook about whether a certain combination of ingredients will please or displease. In effect, the wise man is the measure of things (179B). Socrates now investigates the metaphysical validity of Heraclitus’s ideas, which, he says, underlie Protagorean relativism (179D-183B).

Theodorus subjects Heraclitus and his followers to a great deal of abuse: talking to them is like talking to maniacs, for they never stay in one place, always shifting about, speaking in oracular mysteries, never agreeing with one another or even with their own minds. There are no teachers or pupils among them, Theodorus continues, for each gets his inspiration wherever he can, and none of them thinks anyone else knows anything. It is most clever of Plato to put this criticism of Heraclitus and his band into the mouth of Theodorus rather than of Socrates, for it would be unseemly to have Socrates criticize philosophers after having just praised them. We see in the criticism, which Socrates takes up, the inescapable fact that not all philosophy is laudable: there are philosophers, and there are philosophers. Perhaps they will all do badly in a court of law, but their clumsiness in court does not show an equal hold on truth. Socrates mentions, without additional comment or critique, Parmenides and his followers, who declare just the opposite of the Heracliteans—that all is unity and constancy.

Surely both philosophical schools had an insight that they devel­oped: Heraclitus saw the physical world as in flux and change, and surely he was right, for matter, with its atomic motions, is never absolutely stable. Parmenides, on the other hand, looked at ideas and propositions abstracted from physical reality and saw unchanging being. It took the philosophy of Plato to effect a compromise by a system of duality. Of course, his reconciliation of the opposing views was not absolutely satisfying either, for it could not show how they were connected. The mediation between the worlds of being and becoming presents, as Aristotle saw, the principal objection to the received Platonic system. We who are puzzled by the mind-body problem in this century have not escaped from the aporia of our philosophical forebears.

The argument with Theodorus concludes as Socrates shows that it is impossible to speak as a perfect Heraclitean: not only would percep­tions be constantly changing (182E), but our language to describe those changing perceptions would have to be constantly changing to mirror the protean reality. Thus they complete the discussion of Protagoras, agreeing that knowledge is not perception (183C).

Theodorus is again most eager to withdraw from the conversation, but Theaetetus reminds him of his agreement to look into the words of those who claim everything to be at rest, the Parmenideans. Something very strange happens now: Socrates declines to discuss the views of Parmenides. His reasons are several: first, he has a special reverence for Parmenides; second, his words are very difficult, and the thought they express still more difficult; finally, it might do injustice to the question about knowledge, which is the current issue. We can only wonder why Plato’s dialogue takes this strange turn. Can it be that Plato really wants to spare us a very difficult inquiry, one inappropriate for a dialogue? Is he saying that the medium of dialogue cannot sustain a certain level of complexity and keep the audience’s interest?^[12] Can it be that it would be too difficult for young Theaetetus? Can it be that the dialogue will actually take up Parmenidean views anyway, in the discussion about whether or not mistakes are possible-in a discussion that is quite reminiscent of Parmenides?

Theaetetus now returns to the conversation. Socrates decides to speak with great precision, distinguishing between seeing with the eyes and through the eyes. The distinction leads to the observation that there must be a faculty other than sense that tells us that a color is not a sound and that this faculty must exist in the mind. As if to reflect the argument in a compliment, Socrates praises Theaetetus for his hand­someness, a handsomeness of mind, not of body (185E), and in the equivocation we see a quality properly of the body applied by the mind to the intellect. Since, evidently, some things are apprehended by the mind, when, say, one reflects on his perceptions, it 1s clear that knowledge is not perception (186E).

Theaetetus attempts at once a second definition of knowledge: “making judgments.” He quickly corrects the definition to “true judgments,” but even here, he modestly says that if this definition does not work, he’ll try again (187B). Surely Socrates has met a young man as eager for philosophy as himself!

Socrates now expresses anxieties about this latest definition and wonders whether he should bring them up. He is concerned about how false judgment is possible. Theaetetus heroically chides Socrates’ reluctance, recalling Socrates’ notion of leisure (187E). Socrates is grateful for the reminder and takes up the question. How readily Theaetetus has adopted Socratic manners and views! He and Socrates are becoming more and more alike.

Socrates begins the discussion with Parmenidean extremes: either we know something or we don’t (188A). All the possibilities of how a man might err are brought up. Does he confuse two things he does not know—impossible; does he think “what-is-not” about something— also impossible, for to do so would be not to think at all. In the middle of this very equivocal argument Socrates pokes fun at Theaetetus’s oxymoronic way of speaking (189D), when he talks about “truly thinking what is false.” But this way of speaking is not much different from Socrates’ own. Can it be that the mind errs by thinking one thing to be something else (190B)? This does not seem to be possible either, for if one thinks of two things, he must know them; if he thinks only of one, there can be no confusion (190E). It is beginning to look as though false judgment is impossible. Yet, says Socrates, if we agree that it is impossible, all sorts of unnamed absurdities result.

Perhaps, Socrates suggests, it is possible to think something we know is something we don’t know. Sometimes at a distance we confuse one person for someone else. How is such confusion possible? Despite his claim to be a mere midwife with no ideas of his own, Socrates now proposes the comparison of the mind to a block of wax (191C). Memories, according to this similitude, are stored in waxlike imprints of a seal ring. If the wax is hard, the memories remain a long time; if soft, a short time. Socrates then rattles off in an incredible display of complexity all the possibilities in which false opinions are not possible (192A-C). After it, Socrates wants similarly to give all the instances where false judgments are possible. We are grateful to Theaetetus for admitting that he cannot follow Socrates.

Indeed, Socrates’ recitation of the complex list raises the question of the dialogue’s audience. Was the dialogue meant to be heard, read by a slave, as Euclides’ slave is reading to Terpsion, or was the dialogue meant to be studied carefully and precisely? If, as I suppose, the former was the case, then Plato must not have expected his listeners to follow every little detail as it was being rattled off. What he must have wished to communicate was some sense of the complexity of the problem.

With great kindness, Socrates endeavors to clarify the matter for Theaetetus, but Socrates’ clarification leaves him, and us, more con­ fused than ever (192D). Socrates tries again, this time giving concrete examples. Socrates shows that if he does not perceive either Theaete­tus or Theodorus, he can’t confuse them; if he knows only one of them, he can’t confuse them, and if he knows neither, he can’t confuse them. Now Theaetetus understands. Perhaps the point of all this confusion, which could easily have been avoided had Socrates used the same examples in the first place, is a lesson in pedagogy: an example is worth a thousand words.

Continuing his similitude of the wax tablet, Socrates convinces Theaetetus that mistakes occur when the wrong image imprinted in the wax tablet of the mind is put together with a perception (195B). And now, just as we seem to be making progress, Socrates expresses disgust with himself. He has serious doubts. He is not sure that error resides in a bad fitting together of perceptions and thought, for people add numbers incorrectly, even when there is no perception involved (196A-B). In adding incorrectly, one seems to make a mistake about two things, the two numbers that he knows. Thus it appears either that false judgment is impossible or that one can err about two things that he knows. A problem arises in Socrates’ insistence on simplicity: he is looking for a single comprehensive theory that will account for error. Rather than hold on to any good that may be in conclusions already reached, Socrates moves on to a new theory.

To break out of perplexity, Socrates suggests that they very boldly describe what knowing is even though they have not defined knowledge (196D). There is some discussion on the dubious methodology, but in view of the difficulty they find themselves in, they decide to go ahead anyway. They note the extreme difficulty of discussing knowledge without using any words for knowing.

Socrates brings up an altogether different image for the mind, that of an aviary. First he distinguishes between “possessing” and “having,” where a man might possess a coat but not have it on. Thus, he possesses but does not have the coat. In this sense, Socrates suggests, perhaps thoughts are like birds that one might possess and keep in an aviary: though he possesses them all at any given moment, he has only the one that he actually holds on to (197C-198A). This distinction seems to solve the problem of false judgement: one can possess without having a piece of knowledge, and the hypothesis that had been rejected because of a failure to make this distinction in the word “have” is restored. By using “possess” instead of “have,” it is possible to have and not to have knowledge at the same time. This seems a very hopeful development, and Theaetetus agrees to it (199C). But again Socrates has doubts. How could a man fail to recognize something that he knows?

Theaetetus inventively suggests that there might be birds of ignorance flying around in the aviary—a charming suggestion. But Socrates finds fault with the possibility: how then could one know when he had a bird of ignorance or of knowledge? Surely one would think he knew in either case. Putting it into the mouth of an imaginative critic, Socrates raises the problem of ever further pieces of knowledge about knowledge shut up in the ridiculous waxen tablets or aviaries. In short, Socrates destroys his own ideas.

All his imaginative hypotheses fail to reach conclusions.

Of course, we can’t help but observe that if Theaetetus had been responsible for ending the argument, he would have been content numerous times with the conclusions they reached. In each case his satisfaction would have been premature. Persuasive though every attempt at a definition of knowledge or false judgment seemed, upon further examination it proved to be defective. Without Socrates, Theaetetus would not have seen the defects.

Theaetetus admits to being once again in aporia. Socrates asks whether he wants to give up. Not Theaetetus! He’s ready to go on and suggests as a definition of knowledge “true belief” (200E). Socrates suggests that true belief is what lawyers, who operate by the dock, try to achieve. Teachers, unable to teach by the clock, are not able to convince by a method of instilling “true belief” (201B). Lawyers, Socrates argues, may give belief without knowledge, for they may succeed in convicting someone who deserves to be convicted by means of bad evidence.

Theaetetus tries again with a view he has heard: knowledge is “true belief with an account.” In trying to come up with the meaning of “account,” Socrates suggests that names are elements, inexplicable in themselves, meaningful when in combination with other names (202B­ C). Theaetetus is satisfied with Socrates’ formulation, but Socrates has doubts (202D). How can complex things like names be known if the simple elements of which they are composed cannot be known? In a moment the theory seems to have fallen apart, for it seems absurd that one can know an entire syllable “So-” without knowing either “Socrates” or “o.” Perhaps, says Socrates, we ought to think of the syllable as the elemental unity. The discussion turns on whether a whole has parts and on whether, if a thing is a unit, the parts are differentiated. Things with no parts ought to be the same throughout. The problem of course is that with numbers a whole is equal to the sum of the parts, and in terms of quantity the sum is the same as the parts. Thus 12 = 2 x 6 or 5 + 7. Similarly, if a syllable is a unity, it ought not to be divisible into separate parts even when the parts are different. If the syllable is an unknowable unity, the letters cannot be knowable either (205E).^[13] But now Socrates argues that experience indicates the opposite of the conclusion they have reached: experience seems to show that the elements are what people know best of all. Whether syllables or musical notes, people are most familiar with these (206B). Again, despite the fact that Theaetetus has agreed with the whole argument up to this point, Theaetetus assents to its rejection.

What is the meaning of “giving an account?” asks Socrates. Does it mean giving a catalogue of all the elements? Theaetetus agrees to this until it is shown that one might be able to spell a word without having a grammarian’s knowledge of the elements (208B-C). Knowing how to spell a word is true belief with an account of the elements, but it is not the same as knowledge.^[14]

Socrates suggests the possibility that knowledge is the ability to cite the way in which a thing differs from everything else (208C). When Socrates gives an example of this definition (208D), it seems very plausible, and Theaetetus agrees at once. But yet again Socrates has doubts. How would it be possible for him to be acquainted with Theaetetus only enough to have a “notion” of him. How could he have a notion of Theaetetus without knowing how Theaetetus differed from others? And if “giving an account” means “to know the differentia,” then “giving an account” is the same as “knowing.” And so the definition of knowledge turns out to be “knowing,” not very helpful at all.

At this point, still another definition having failed, Socrates returns to his simile of himself as midwife. It appears, he says, that all their children have been windbags and not worth rearing. He concludes with two messages to Theaetetus: (1) the conversation they have had will help Theaetetus think better about knowledge another time; and (2) even if their inquiries have been barren, they will keep Theaetetus humble and agreeable. But now Socrates must go to the courthouse to answer the indictment. He suggests that they meet the next morning.

Socrates’ final words would be obviously appropriate if they were addressed to one of his obnoxious interlocutors, one of the braggart ignoramuses that he met daily. Instead, the words are spoken to the most modest, eager companion we have seen. It is very frequently the braggart who finds it necessary to end the conversation; here, it is Socrates. We have, however, seen the eager Theaetetus agree over and over again to conclusions he thought final, only to see the conclusion rejected a moment later. Perhaps, then, Socrates’ warning is real, this warning against that insidious form of intellectual laziness that is willing to accept plausible solutions without sufficient scrutiny.

If the dialogue be a memorial to Theaetetus, I suggest that what Plato had in mind was this: there could be no greater praise of Theaetetus than to make him an image of Socrates. To do so, Plato had first to demolish Theaetetus’s intellectual forebear Protagoras, Theodorus’s friend and teacher. This done and sophistic relativism rejected, Plato could show Theaetetus and Socrates at work together on a topic of great importance—knowledge, a topic, it must be recalled, that would have meaning only if Protagoras was proved false.

Though the dialogue is aporetic, some progress seems to have been made, albeit of a negative nature. ^[15] The warnings about modesty at the end remind those who actually knew Theaetetus that he did in fact preserve his personal qualities till the end of his life—as we know from the introductory scene between Terpsion and Euclides. In the dialogue, Theaetetus’s most charming quality is his philosophical endurance: he never grows weary, never reluctant to pursue the solution. Perhaps this kind of persistence was a quality of his in life, and Plato wishes to show that it was already manifest in his youth.

One final question remains: what does Plato mean by the extraordi­nary simile of the midwife and the many echoes of it throughout the dialogue? When argument after argument is generated, sustained, and refuted by leading questions from Socrates, we cannot take the simile at face value. Perhaps Plato meant it as a statement of Socrates’ modesty, an adult equivalent to Theaetetus’ s youthful modesty. In this way we might once again see how little he corrupted the youth.