Anciently, in tragedy, it was only the chorus who did the whole work of the play; but subsequently, Thespis introduced one actor for the sake of giving the chorus some rest, and Aeschylus added a second, and Sophocles a third, and so they made tragedy complete. So in the same manner, philosophical discourse was originally uniform, concerning itself solely about natural philosophy; then Socrates added to it a second character, the ethical; and Plato a third, the dialectic, and so he brought philosophy to perfection.
But Thrasybulus says that he published his dialogues as the dramatic poets published their tetralogies. For, they contended with four plays, (and at four festivals, the Dionysiac, the Lenaean, the Panathenaean, and the Chytri), one of which was a satiric drama, and the whole four plays were called a tetralogy. Now, people say, the whole of his genuine dialogues amount to fifty-six; the treatise on the Republic being divided into ten books, (which Phavorinus, in the second book of his Universal History, says may be found almost entire in the Contradictions of Protagoras), and that on Laws into twelve. And there are nine tetralogies, if we consider the Republic as occupying the place of one book, and the Laws of another. He arranges, therefore, the first tetralogy of these dialogues which have a common subject, wishing to show what sort of life that of the philosopher may have been. And he uses two titles for each separate book, taking one from the name of the principal speaker, and the other from the subject.
This tetralogy then, which is the first, is commenced by the Euthyphron, or what is Holy; and that dialogue is a tentative one. The second is the Defense of Socrates, a moral one. The third is the Criton, or What is to be done, a moral one. The fourth is the Phaedo, or the Dialogue on the Soul, a moral one.
The second tetralogy is that of which the first piece is the Cratylus, or the correctness of names, a logical one. The Theaetetus, or Knowledge, a tentative one. The Sophist, or a dialogue on the Existent, a logical one. The Statesman, or a dialogue of Monarchy, a logical one.
The first dialogue in the third tetralogy is the Parmenides, or a dialogue of Ideas, a logical one. The second is the Philebus, or on Pleasure, a moral one. The Banquet, or on the Good, a moral one. The Phaedrus, or on Love, a moral one.
The fourth tetralogy opens with the Alcibiades, or a treatise on the Nature of Man, a midwife-like work. The second Alcibiades, or on Prayer, a piece of the same character. The Hipparchus, or on the Love of Gain, a moral one. The Rival Lovers, or a treatise on Philosophy, a moral one.
The first dialogue in the fifth is the Theages, or another treatise on Philosophy, another midwife-like work. The Charmides, or on Temperance, a tentative essay. The Laches, or on Manly Courage, midwife-like. The Lysis, or a dissertation on Friendship, also midwife-like.
The sixth tetralogy commences with the Euthydemus, or the Disputatious Man, a distinctive dialogue. Then comes the Protagoras, or the Sophists, a demonstrative one. The Gorgias, or a dissertation on Rhetoric, another distinctive one. And the Meno, or on Virtue, a tentative dialogue.
The seventh begins with the two Hippiases. The first being a dissertation on the Beautiful, the second one on Falsehood, both distinctive. The third is the Ion, or a dissertation on the Iliad, a tentative one. The fourth is the Menexenus, or the Funeral Oration, a moral one.
The first dialogue in the eighth is the Clitophon, or the Exhortation, a moral piece. Then comes the Republic, or the treatise on Justice, a political one. The Timaeus, or a dissertation on Nature, a dialogue on Natural Philosophy. And the Critias, or Atlanticus, a moral one.
The ninth begins with the Minos, or a treatise on Law, a political work. The Laws, or a dissertation on Legislation, another political work. The Epinomis, or the Nocturnal Conversation, or the Philosopher, a third political one.
And this last tetralogy is completed by thirteen epistles, all moral; to which is prefixed as a motto, εὖ πράττειν, just as Epicurus inscribed on his εὖ διάγειν, and Cleon on his χαίρειν. They are, one letter to Aristodemus, two to Archytas, four to Dionysius, one to Hermeias, Erastus, and Coriscus, one to Leodamas, one to Dion, one to Perdiccas, and two to the friends of Dion.
And this is the way in which some people divide his works. But others, among whom is Aristophanes, the grammarian, arrange his dialogues in trilogies; and they make the first to consist of the Republic, the Timaeus, and the Critias.
The second of the Sophist, the Statesman, the Cratylus.
The third of the Laws, the Minos, the Epinomis.
The fourth of the Theaetetus, the Euthyphro, the Defense of Socrates.
The fifth of the Crito, the Phaedo, the Epistles.
And the rest they arrange singly and independently, without any regular order. And some authors, as has been said already, place the Republic at the head of his works: others begin with the Greater Alcibiades: others with the Theages; some with the Euthyphro, others with the Clitophon; some with the Timaeus, some with the Phaedrus, others again with the Theaetetus. Many make the Defense of Socrates the first piece.
There are some dialogues attributed to him which are confessedly spurious. The Midon, or the Horse-breeder; the Eryxias, or Erasistratus; the Alcyon; the Acephali, or Sisyphi; the Axiochus; the Phaeacians; the Demodorus; the Chelidon; the Seventh; the Epimenides. Of which the Alcyon is believed to be the work of a man named Leon; as Phavorinus tells us in the seventh book of his Commentaries.
But he employs a great variety of terms in order to render his philosophical system unintelligible to the ignorant. In his phraseology he considers wisdom as the knowledge of things which can be understood by the intellect, and which have a real existence: which has the Gods for its object, and the soul as unconnected with the body. He also, with a peculiarity of expression, calls wisdom also philosophy, which he explains as a desire for divine wisdom. But wisdom and experience are also used by him in their common acceptation; as, for instance, when he calls an artisan wise (σοφὸς). He also uses the same words in different senses at different times. Accordingly he uses φαῦλος in the sense of ἁπλοῦς, “simple,” in which meaning also the word occurs in Euripides, in the Licymonius, where the poet speaks of Hercules in the following terms:
Mean looking (φαῦλος), rude, virtuous in great affairs, Measuring all wisdom by its last results, A hero unrefined in speech.
But Plato uses the word sometimes even for what is beautiful; and sometimes for small and insignificant; and very often he uses different words to express the same idea. Accordingly, besides the word ἰδέα for a class, he uses also εἶδος, and γένος, and παράδειγμα, and ἀρχὴ, and αἴτιον. Sometimes he uses opposite expressions for the same thing; accordingly, he says that it is an object of sensation that exists, while at other times he says it is that which does not exist; speaking of it as existing because of its origin, and as nonexistent with reference to its continual changes. Then again, he defines his ἰδέα as something which is neither moving nor stationary, at one time calling the same thing, at another time one thing, at a third time many things. And he is in the habit of doing this in many instances.
And the explanation of his arguments is threefold. For first of all, it is necessary to explain what each thing that is said is; secondly, on what account it is said, whether because of its bearing on the principal point, or figuratively, and whether it is said for the purpose of establishing an opinion of his own, or of refuting the arguments brought forward by the other party to the conversation; and thirdly, whether it has been said truly.
But since there are some particular marks put in his books, we must also say something about them. × indicates peculiar expressions and figures of speech, and generally any peculiarities of Plato’s style. When doubled it points to the doctrines and peculiar opinions of Plato; ※ when dotted all round, points to some select bits of beautiful writing. When doubled and dotted it indicates corrections of some passages. A dotted obelus indicates hasty disapprovals. An inverted sigma dotted all round points out passages which may be taken in a double sense, and transpositions of words. The Ceraunium indicates a connection of philosophical ideas. An asterisk points out an agreement in doctrine. And an obelus marks the rejection of the expression or of the passage. These then are the marginal marks which occur, and the writings of which Plato was the author: which, as Antigonus the Carystian says, in his treatise on Zeno, when they had been but lately published, brought in some gain to the possessors, if anyone else was desirous of reading them.
These now were his chief opinions. He affirmed that the soul was immortal and clothed in many bodies successively, and that its first principle was number, and that the first principle of the body was geometry. And he defined it as an abstract idea of spirit diffused in every direction. He said also that it was self-moving and threefold. For that that part of it which was capable of reasoning was situated in the head, that that portion which was affected by passion was seated around the heart, and that which was appetitive was placed around the navel and the liver. And that it is placed in the middle of the body, and embraces it at the same time in all its parts, and that it consists of elements; and that when it is divided according to harmonic intervals it forms two connected circles, of which the inner circle is divided into six portions, and makes in all seven circles; and that this is placed on the left hand of the diameter, and situated in the interior. But the other is on the right hand of the same line; on which account, and because it is one only, it is the superior of the two. For the other is divided internally; and this too, is the circle of that which is always the same; the other, the circle of that which is changeable and different. And the one he says is the motion of the soul, but the other is the motion of the universe and of the planets.