Main theme: Good rhetorician needs to be a philosopher and must know how to use the method collection and division, the new approach to dialectic. Critique of Sophists' view that a good rhetorician need not know the truth of the subject matter of which he spoke. Plato also holds that one must know the souls of those who are to be persuaded as well. And ultimately there is a higher goal than mere persuasion: the purgation and perfection of the soul and serving the gods. Just as the good physician must know the body, so must the good rhetorician know the soul.

263ff. Problems with Lysias' speech. He did not define love and he put his conclusion first rather than arguing for it. He did not use any cogent principle of composition. A discourse should, as logic and the cosmos itself, be seen as a living body.

Late in the dialogue, we hear a theme made famous in the "Seventh Letter": the spoken word should be trusted far more than the written word. Socrates would have definitely agreed with that. Oral discourse and argument stressed in the Academy.

Little is known about Phaedrus other than that he was known as Socrates’ favorite disciple. He must likely one of Lysias' lovers. Was a lover to Socrates, too? There are lots of homoerotic allusions to something like "let’s doing a little ‘rolling’ in the meadows."

Gilbert Ryle believes the dialogue was written during his third trip to Syracuse in 361. It may have been presented at the Olympics of 360 under the topic "About Love." But the dialogue is really about rhetoric and Plato is announcing that he is now teaching rhetoric at the Academy--in the new philosophical form that Socrates proposes.

Another Plato scholar Nicholas White claims that this dialogue must be written after the Republic because of a recognition that language is most complex than the simple views of Phaedo and Republic. No simple correspondence between words and Forms. It is clear now that people will call to mind various forms in response to just one word. The word "love" and its various associations show this truth clearly in the Phaedrus. And there are at least four phenomena which can be associated with the word "madness." In the complexity of the love discussion, this dialogue is obviously later than the Symposium.


True love must seek something higher than physical beauty. It must look for the Form of Beauty which is embodied in any beautiful thing.

237d: the innate desire for pleasure must be disciplined by the acquired judgment (doxa) that aims at what is best. Must be a harmony between the two, not as earlier, a complete victory of the latter over the former.

FOUR TYPES OF MADNESS (mania). Don't be confused by the argument that the temperate friend is to be preferred to the intempate one in frenzy (245b).

(1) The greatest things are received because of madness, the fit which the Pythoness goes into at Delphi, the priestess at Dodona, and the prophetess Sibyl. This madness is a divine gift. This is much superior to human sanity. Patron god is Apollo.

(2) the madness of possession and illness, which upon prayer and ritual, leads to both prophecy and healing. The person "has afforded a release from his present calamity to one who is truly possessed, and duly out of his mind" (244e). Patron god is Dionysos

(3) the madness of the Muses. This form takes hold of "a delicate and virgin soul, and there inspiring frenzy, awakens lyrical and all other numbers." Such a person is allowed into the temple, but the sane person is barred. Patron gods are the Muses.

(4) the madness of the lover, who goes wild at the sight of true beauty. (Patron god is Eros, son of Aphrodite.) He "is transported with the recollection of the true beauty; he would like to fly away, but he cannot; he is like a bird fluttering and looking upward and careless of the world below; and he is therefore thought to be made." The most beautiful youths of something divine in them, and it is not irrational to think that one must sacrifice everything for him. Quote at 251ab. The soul's wings begin to grow at such a heavenly sight. There is much agitation and emotion--sort of like cutting teeth. Emotion particles float through the air. (Influence of atomism?) The soul is "pierced and maddened and pained" (251d). Wouldn't anyone go crazy to be separated from such a perfect expression of true reality. The lover then ends up neglecting everything because of his obsession with Beauty itself.

253a: Love triangle between lover, beloved, and the patron god. They both then receive the character and disposition of that God, "so far as man can participate in God."


Another argument for the immortality of the soul: "Every soul is immortal since the ever-moving is immortal" (245c) Soul is a self-moving mover, the source of all movement in the cosmos. If it stopped moving, then all motion would stop. Motion continues, so the soul is indestructible. The argument appears to be circular.

Just as the method of division gives an explanation for confusion in truth, so does the chariot metaphor give a reason for wrongdoing that replaces Soc's view that evil is done out of ignorance, or the Phaedo's view that it's merely the body's fault. Plato introduces his own view of the "divided" self. Body as prison and a goal of escaping it is now replaced with a view that one should maintain harmony in the soul. Gnostic dualism of Phaedo is replaced by organicism of the Republic and Phaedrus. A unitary soul trapped in a body is replaced by a tripartite soul at war with itself.

Chariot metaphor implies three personality types: "the person in whom appetite dominates becomes at best a lover of spectacle, one who delights in sensuous beauty without seeking to know its eternal archetype; the man in whom the spirited element (thymos) dominates, a man of action; the person in whom intellect dominates, a philosopher" (Melling, 74). Three divisions of the Republic and its origins are probably found in Pythagorean theory.

Back to Madness. The irrational behavior of the lover is caused the black steed? Or has Socrates convinced us that it is totally justified? After the black steed has been tamed, then "the soul of the lover follows the beloved in modesty an holy fear" (254e). But do they do "it" or not. Not clear at 256. The black steed does really want to do "it." Yes, they do, but not without censure from reason.

True lovers will be released into heaven after 1,000 years (?), but mere friends will have to wait 9,000 more years.


According to the Law of Destiny, the soul which has seen the most being (truth) enters into the body of a philosopher or a lover of beauty; those who have seen truth of a second degree shall be warriors; third class souls shall be politicians, economists, or traders; fourth string souls shall be gymnists or physicians; the fifth shall prophets or hierophants (lovers of the sacred); the sixth shall be a poet or an imitative artist; the seventh will be an artisan or farmer; the eighth, sophist or demagogue; and finally the last shall be a tyrant. These souls are on probation for 10,000 years; and they cannot regrow their wings, except philosophers and lovers, who may get out after 3,000 years.

DOCTRINE OF RECOLLECTION. "Every soul of man has in the way of nature beheld true being" (249e). But very few are lest with an adequate recollection of true reality and now see through a glass darkly.


Also there is a development of dialectic into the method of collection and division (diairesis, synagogue), which will dominate the later works, e.g., the Sophist. This form of dialectic is a divine activity: "And if I think any other man is able to see things that can naturally be collected into one and divided into many, him I follow after and 'walk in his footsteps as if he were a god" (Loeb, 266c).

One can see this in the word dia-lectic itself. Emphasizing meaning of dia-, one gets the idea of dividing; but emphasizing meanings of lego one gets synthesis. The word diakrino is used in the Sophist (253e) to mean distinguishing one Form from another.

"Dialectic in the dialogues up to the Republic seems formally to be one thing, a technique of systematic questioning, but applied to different object-matter with different functions and different results. The dialectic of the later dialogues is not a technique of questioning; it is a process of systematic classification" (Melling, 140). Early dialogues, validity is within the framework of speaker and interlocuter; later dialectic takes on universal significance.

This method seems to replace the method of hypothesis introduced in the Phaedo, and it appears to be an advance over the Republic, where we are assured that the form of the Good illuminates all things. Plato now struggles with the problem of how even philosophers make mistakes. Nicholas White believes that Plato should have refurbished the hypothetical method.

249c: First mention of the method: "For a man must have intelligence (logos) by what is called the Idea (eidos), a unity gathered together by reason (logos) from the many particulars of sense. This is the recollection of those things which our soul once saw which following God. . . in beholding which He is what He is. "

"We bring a dispersed plurality under a single form (idea), seeing it all together. . . [whereas in division] we are enabled to divide into forms, following the objective articulation (natural joints); we are not to attempt to hack off parts like a clumsy butcher (bad carver, Loeb). . ." (265de). There will be, as in Duns Scotus, a natural end of division. The body of the real is like a carcass which we must leave to expert butchers.

Problems with dividing Forms: If there is a form of Human, is there a subform Barbarian, Egyptian, Persian, Caucasian, Negroid, Mongoloid? In the Statesman it is denied that the subclass of non-Greeks is a real group, and hence a separate Form. The method of division is designed to separate real entities from bogus ones.

Obviously widely taught in the Academy, because it was widely satirized too.


Cornford: PARMENIDES, THEAETETUS, SOPHIST, AND STATESMAN deliberately written to be read in order. Reference made in each of the following to its predecessor. The Theaetetus (183e) alludes to the meeting in the Parmenides, and the Theaetetus ends with a promise of an appointment which is met in the Sophist and the latter is openly referred to in the Statesman. They, or parts of them, may have been composed out of order, but still designed to be read in this order.

Does Socrates' reference that his "head has been broken" in argument before (169c) encountering "heroes in debate" point to the defeat he experienced at the hands of Parmenides and Zeno?

It is significant that the Eleatic school should dominate in these dialogues: as Parmenides and Zeno in the Parmenides and the Eleatic "stranger" in the Sophist and the Statesman.

Middle dialogues--MENO, PHAEDO, TIMEAUS, PHILEBUS, REPUBLIC, AND LAWS--written for an educated lay audience, while the last four obviously written for philosophers only.

Epistemological proof of the immortality of the soul in the Meno: If the truth of things is always in the soul, and if truth is eternal, then the soul is immortal. This argument is based on the Theory of Recollection (anamnesis). Stands clearly against empiricist views of perception: forms and the soul were mere eidola, related to the eidola of atomist theories of perception.

Cornford (4): "The separation of the Platonic Forms from any dependence on material things went with the separation of the soul which knows them from any dependence on the physical organism." The Phaedo argues for both of these conclusions. "Separate" in the Greek is choris, and the separation is chorismos (Phaedo 67d). The psyche of breath is transformed into a psyche of Nous.

In the Parmenides chorismos also means the separation among the forms themselves in addition to the ontological separation between the realm of Forms and the world of appearance. How can they combine and divide? This issue is taken up in the Sophist. The proposition "Likeness is different from Unlikeness" has its meaning exclusively in the realm of Forms. No problem os participation here at all, but one of how the forms relate to one another.


(written 362 BCE according to Ryle)

Takes place 445 B.C.E.

Parmenides 65 years old

Zeno 40 years old

Socrates 24 years old

Theaetetus 165 b. younger man should answer; and at 169 c: my head has been broken in argument with "heroes of debate."

Society boasts that the Theory of Forums can solve the problem of the One and the Many.

Sensible things can be one and many at the same time, but the Forms Unity and Plurality of course exclude each other.


Phaedo: opposite forms fleeing, e.g., at the approach of death the Form Life "flees" from the body.  Even here then we have a problem: Does not the Form of Plurality have to flee when the guy is participating in the Form of Unity. If he is both a unity and has plural parts, then both Forms cannot be in him at the same time.  Let's look at the following diagrams, first to see if we can get it to work in the first diagram and see the contractions in the second diagram.


130c: Parmenides: Are there Forms for hair, mud, and dirt?

Socrates: I try to avoid thinking of these ... there is "nothing without an idea (Form)."

Parmenides: You're still young, Socrates, but you'll get better.

Parmenides: The doctrine of participation. How does it work? Does each thing partake of the Form as whole or just part of the whole.

Day Analogy vs. Sail Analogy.

The former is too abstract (but it is really?) and the latter divides an indivisible Form.

131c: Parmenides: If you divide up Greatness then the parts will be less great than the whole. Parts of Equality less equal?!

When one thinks of a great thing and the Form Greatness, the mind can easily think of a third thing greater. Infinite regress.

132 The "Third or Fourth or Fifth Man" Argument


Does the Form of Humanity have all human qualities of body and soul? If not, then it can the essence of an individual human only in a universal sense that will completely deny the reality of individual things. Parmenidean monism appears to the result of this.

132c: Socrates (backtracking): Let's say that the Forms are just ideas (noemata as objects of noesis). Parmenides: But thoughts must be thoughts of something, right? This leads right back to Forms as transcendental objects, the original theory

Socrates (back-tracking even more): Let's make them fixed patterns (eidola) in nature.

Forms as immanent? (This is Aristotle's position.) Or fixed patterns in the World of Forms? Given the talk about resemblance the latter must be true.

Parmenides: So, individuals don't actually partake of the Forms, they just resemble them, or are like them?


Form of Largness                                         Making the large thing resemble

                                                                               the Form Large.


Individual large thing

But "Some further idea of likeness will always be coming to light" ad infinitum. Is it really infinite regress? Likeness is intelligibly self-predicating whereas "humanity" is not. Logical constants work well as Forms, as is suggested in the Theaetetus.

What's wrong with the Form of Likeness being higher than other Forms. Plato admits to a hierarchy of Forms.

133c: Parmenides: Absolute essences cannot exist in us, because they would no longer be absolute.

                                    Master <==========> Slave


                                    Knowledge <========> Truth

____________________________________ Chorismos

Ontological "gap" -- a great chasm of being

                                        knowledge <========> truth (doxa)

APPEARANCES                 master <==========> slave


A slave is not owned by Master but by master, etc. So the Forms, because of chorismos and the collapse of the doctrine of participation, cannot be known to us. God not knowing us or us knowing God would not bother Aristotle.

Isn't there a solution that Socrates has overlooked? The soul as the mediary between the two worlds? Parmenides's probable response: If the soul is immortal, unchanging, etc., it will be above the line, not "riding" the line.

135b: "Every individual thing has its own determinate idea (Form) which is always one and the same."

Aristotle's position again.


Philosophy begins in wonder (155d). Earlier reference: Iris (Philosophy) is the daughter of Thaumas (wonder)(Cratylus 398d, 408b).

The dialogue may be dated about 369. (Nicholas White says 367.) Theaetetus would have been about 50 in the introduction, but he is only a lad when the main dialogue pretends to take place, a little before the death of Socrates, for he is on his way to the Archon court, where he also has time to dialogue with Euthyphro as well. Theodorus made predictions of his greatness and Socrates will test this.

Like the early dialogues in ending in several aporias, although less dramatic than Meno or Euthyphro.

No mention of the Forms because Plato being scrupulously fair to the opposition? Or, á la Ryle, Plato no longer believes in the Forms. Socrates does not use Forms in Sophist, but Plato introduces instead Friends of the Forms.

Forms are not there because it pretends to be an early dialogue? But an even earlier discussion (viz. the Parmenides) assumes the Forms.

Is this like the second voyage of Parmenides: seeing how well one can do in the world of appearance without bringing in the Forms? Or better: to see how badly things go without the Forms? Cornford: "The Forms are excluded in order that we may see how we can get on without them; and the negative conclusion of the whole discussion means that, as Plato had taught ever since the discovery of the Forms, without them there is no knowledge at all" (28).

But Cornford argues that the Forms are there just below the surface. The Form of Man at 174b and moral forms at 175c. In fact, Cornford believes that this whole digression is essentially a summary of the argument of the Republic.

Forms as logical constants implied at 185e--existence, likeness, difference, even, odd--just categories of the mind now? No, says Cornford: they are Forms. The form of Man falls to the Third Man, but the moral forms and logical constants do not.

But does bringing in the Forms help us with any of the puzzles, such as the one at 154c about the dice. More or less cannot be a permanent quality of things.

Or Tallness and Shortness at 155b. We end up with the absurdities of the Phaedo with the forms Large and Small retreating and advancing. Appears as if the Protagorean solution is to be preferred. A Tallness in us, as a permanent quality, cannot hold.

Cornford: Plato has given up that idea that qualities such as hot, cold, colors, large, etc., are forms.

Finally, why does Socrates produce such poor examples of logos at the end? Why not the logic of the Forms itself?

Sophia=episteme (145E); philogos means passion for argument. Contrast this with the thesis under consideration: aisthesis=episteme, where aisthesis is broadly interpreted to include internal experience as well as external sense perception.

Why are Protagoras and Heraclitus introduced? What justification can be given for putting them together? Not a true elenchus where the question is allowed to develop in question and answer without any appeal to authority or any added information. Theaetetus' definition is not adulterated with extraneous implications and interpretations. He should have objected. The early Socrates would have done this out of Socrates ignorance.


(1) It must be infallible; and (2) it must be of reality. Protagoras' theory seems definitely to fulfill (1) and in an odd way also (2) as esse est percipi (Latin for being is to be perceived; George Berkeley’s famous formulation of empiricism). We cannot even deny that the dreamer has experienced something. The question of course is whether the dreamer has experienced reality.

Cornford believes that Protagoras probably didn't make the critical realist's distinction between the sense object and real object, but supported a naive realist position--that opposite qualities exist in the things themselves. Appears to be Anaxagoras' view (quote Cornford 34-5); indeed, the view of 5th Century Greek philosophy East and West.

"Secret Doctrine": the wind itself is neither warm nor cold, but these qualities come into being when the object meets a perceiver.

But isn't the original position, with the doctrine of flux, really more like phenomenalism, and the secret doctrine more like hypercritical realism? In the latter, object in flux having power to affect.

Plato's view of sense data and objects of sense, just some "queer doctrines" (163a) attributed to Protagoras?

Full introduction of Heraclitian philosophy: all things really are not; rather, they are constantly becoming what they "ara" and then becoming what they "are not."

Reformulation of Protagoras after merged with Heraclitus: "I am the measure of what is, where what is, is really becoming, not being.

Cornford: this is really a Platonic doctrine as well: what we perceive is always becoming and that is the reason why perception cannot be knowledge.

The measure is not a norm for even the individual, for we are constantly changing and cannot step into the same river twice. Radical Heraclitean Cratylus made to concede that one cannot step into the river in the first place!


1. Why not the pig or baboon the measure? Protagoras' answer would have to be Yes. But since they do reason, they don't judge the results of what they measure. Humans do, and they can see that some rules for living are more useful (more "true") than others. Actually don't animals make the same "judgments" in natural selection as well?

2. If each person's opinion is equally true, then why pay teachers for their wisdom? Because some people make better judgments than others, and they might be able to persuade you to give your opinions, which have less utility than an expert's.

3. Turning the Tables (peritrope) on Protagoras. Any belief that homo mensura is false must be true by virtue of homo mensura itself, so homo mensura is false. Reductio ad absurdum as well. Homo mensura is self defeating and self destructing.

Homo mensura is correct only for sensations, not for judgments, for true judgments are connected to the real.


1. Do we always know what we perceive? Socrates' example of hearing a foreign language and Thea's clever response. We know the shape and color of the letters and sounds, and we would know cognates as well. Witt: when do we start knowing a foreign language?

2. How do we know from memory? If memory is not perception, then this is a sound objection, but a broad interpretation of aisthesis could take care of this. Inner sense as well as outer sense.

3. How do the sense organs know common qualities of different senses? The eye can only see not smell or taste, and the ear can only hear and not feel. But we constantly think about common qualities that sounds and sights have, such as they are the same, they are two, etc. Only thought (dianoia) coming from a mind (psyche) can do this. So not all knowledge is perception.


Comparison with the Buddhist Questions of Milinda. See your handout.

Episteme = doxa + logos. Instead the three aborted "wind bags" for logos, why not (following Melling) go back to the Meno's suggestion that a belief is knowledge only when one has uncovered its true being (logos)? Forms again.

THE THEAETETUS (commentary by Stephanus pages).

143: How the dialogue was written.

Two interlocutors: Theodorus the Cyrenian, a geometer; and Theaetetus, student of Theodorus, who will become one of the great students of the Academy. Also a geometer, but not very beautiful (144). Both he and Socrates have snub noses.

146a: Socrates' "love of conversation" (philo + logos = philologia); "love of discussion" "passion for argument" philo + sophia = love of wisdom

Main Question of dialogue: What is knowledge (episteme)?

146e: We want to know episteme in the abstract, not particular forms of knowledge.

149: Socrates as the midwife of knowledge

150b: I look after souls while they are in labor. I judge whether the "issue" is good or bad. I"m barren of wisdom like midwives are barren. The God (Apollo?) compels me to do it.

150d: Divine grace is necessary for philosophical progress? Only to aid in the birth of one's own ideas and knowledge; therefore, the philosophical integrity of dialectic remains intact?

151e: To the main point: Theaetetus: Knowledge is perception (epistémé = aisthesis

This is the Sophists' position (Protagoras).

152b: What about the same wind blowing and one person perceives it to be cold - the other person, hot? Different knowledge for each? Relativism?

152c: Perception is always of existence and therefore unerring?


(1) It must be infallible and unerring

(2) It must be of reality

Does knowledge as perception fulfill these two criteria?

(1) Yes. Optical illusion - can't deny that one perceives the appearance of water. Wind: hot or cold; can't deny our sensations.

(2) Yes, but in an odd way.

esse est percipi (George Berkely's idealism) "being is being perceived"; reality is created in the interaction between sense organs and their objects.

Wind is neither hot nor cold but they (the qualities) come into existence with individual perceptions.

152d: Introduction of the doctrine of flux - "there is no being at all, but only perpetual becoming." Heraclitus

153: "Cogent proof: that motion is the source of what is called being and becoming..." reference to the Phaedrus?

Both physical and mental well-being require motion. So that motion is good and rest is evil.

153d: If heavens stop turning, then all comes to an end.

153e: Scientific theory of color perception: the eye meeting the appropriate motion (light wave); modern view has internal meeting--"between"-- rather than external, as with Socrates.

154b: different for every perceiver. They are simply "appearances" in us (155).

155c: Philosophy begins in wonder. Usually attributed to Aristotle.

156a: the various senses and their sense objects: seeing ---> color; hearing ---> sound, etc.

156de: Color is produced in the air, eye as agent meets object as patient. Eye is filled with "sight" and the object becomes white.

157: Neither sensation or objects of sense have absolute existence, only relative existence.

Everything is becoming and in relation - process philosophy as in A. N. Whitehead (d. 1948).

"being is abolished" - i.e., permanent existence.

Is it right to put Heraclitus and Protagoras together indiscriminately? What's the difference between the two? Heraclitus: All is in flux. Protagoras: homo mensura and knowledge is perception

157d: Is there no permanent good or beautiful, or do they change?

158: The theory knowledge as perception is refuted by the fact the dreams and illusions are obviously false perceptions. For this theory, truth may be more than relative, it may be non-existent.

158b: Anticipation of Descartes: How can I be sure that my waking life is not my dream life? Therefore, we can easily doubt all sensation and perception.

159e: "champions of appearance," the Sophists?

160b: "nothing can become sweet which is sweet to no one." True or false?

160c: "My perception is true to me, being inseparable from my own being." Cannot escape relativism with Protagoras' thesis.

160d: My own perception is unerring even if I'm hallucinating, right?

160e: So, you must be right, Theaetetus, that knowledge is perception. A child is born! Is it a wind-egg or living truth?

161c: Is the pig or baboon the measure of their "things"? If he is right, then dialectic cannot work. Protagoras' answer? Animals do not reason and cannot speak, so they cannot invent the conventions by which human life is organized. Protagoras meant human beings generic, not isolated individuals.

161-162c: Interlude with "stiff" Theodorus.

163b: Discussion of memory. There is knowledge by memory without the direct aid of the senses. One knows what one has seen even after closing the eyes.

164b: But from your thesis: if seeing is knowing, then it follows that not-seeing is not knowing.

165b: "Let the younger answer: he will incur less disgrace if he is discomfited..." Set-up of Parmenides?

166-168: Defense of dialectic and tripping people up. The dialectician will correct the interlocutor only when necessary. Your partner then will see his own faults and not blame you. (Is this what happens in the early dialogues?)

169c: Socrates has broken his head in argument.

170c: Socrates: We all assume that some persons are wiser than others, right? So opinions are always true, or sometimes true, sometimes false? Must be the latter. But given homo mensura, then all opinions must be true. Reductio ad absurdum to pay teachers.

"Turning the tables" (peritropé) on Protagoras: Any belief that homo mensura is false must be true by virtue of homo mensura itself. Reductio ad absurdum. Homo mensura must be false. Protagoras' response?

171d: Theodorus: Aren't we hitting Protagoras a little too hard?

172ff: True judgement and knowledge must be connected to reality, not to sensation.

180: Parody on Heraclitus. Is it fair? No acknowledgment of logos doctrine.

180e: Parmenides' position.

182ff: Repeat of theory of sense perception.

183: If everything is in motion, then we can never say whether a thing is or is not. If true knowledge is connected to reality, then we have foundered on relativism again.

183c: Theodorus retires, acknowledging that Protagoras-Heraclitus is defeated.

183e: I met Parmenides when I was a young man. Reference to Parmenides.

184c: Do we see with eyes or through the eyes? Ears, too? Theaetetas: through the senses. Socrates: through the senses to the soul, of which the senses are its instruments.

185: See with the eyes; hear with the ears - not hear with eyes, etc. But there is a common, unified perception of things, right?

185c: Reference to the Forms? (175c, too): being, non-being, sameness, difference. Which faculty perceives these? Are they not necessary for knowledge?

Theaetetus: "Mind, by a power of her own, contemplates such common properties." mind = psyche And only mind can hear, see, touch, and taste at the same time. And only the mind can judge that this yellow thing is also the same thing as the thing that tasted sweet. True knowledge obviously requires more than sense perception.

186: Forms now referred to as "classes"-- merely concepts or better as logical constants?

186c: One cannot attain truth without attaining being. Second "mark" of Knowledge must be being (i.e. permanent existence) not becoming.

186d: Knowledge does not consist in impressions of sense, but in reasoning about them. episteme = aisthesis + logos

210b: elenchus as destroying hubris

210c: Tomorrow morning I will go to the "grand jury" (King Archon's court). Scene of the Euthyphro, an early dialogue!

Theaetetas: Summary of the Arguments

1. Relativism

2. Dreaming and illusion are false knowledge

3. Do we always know what we perceive?

4. We know from memory, but it's not perception.

5. We have a knowledge of common qualities and logical forms (sameness, difference) that the individual senses don't give.

Against Homo Mensura

1. Why not animals as the measure of things?

2. If each person's opinion is equally true, then why pay teachers for their "wisdom".

3. Turning the Tables: Any belief that homo mensura is false must be true by virtue of homo mensura.