himself had given. From asking, Is virtue one? Can virtue be taught? Plato passes on to ask, What is unity? What are knowledge and being? From criticizing imperfect modes of teaching virtue, he has begun to speculate about the right and wrong uses of the intellect, and from dramatic portraits of the individual Protagoras or Gorgias goes on to the ideal delineation of the sophist. He has entered upon the “longer way,” and is no longer contented with mere “hypotheses.” With this demand for scientific precision his conception of the ideas themselves is modified, and he strives anew to conceive of them in relation to one another, to the mind, and to the world. As the balance of ethical truth was restored by admitting an unconscious (or inspired) conformity to reason, so now a fresh attempt is made on the intellectual side to bridge the gulf between sense and knowledge.
This endeavour involves, not only an expansion of the method
of Socrates, but an examination of the earlier philosophies from
which Socrates had turned away. Their influence on Plato has
been traceable in the preceding dialogues, though, except in the
case of Pythagoreanism (Gorg., Phaed., Rep.) it has been mostly
indirect and casual. But in these dialectical dialogues he manifests
his serious conviction that the contemporary fallacies which
formed the chief hindrance to inquiry were deeply rooted in
forms of thought created by earlier thinkers, above all by
Heraclitus and Parmenides. To the exclusiveness of their first
principles as held by their followers Plato attributed the
barrennesss and impracticable unreality of many discussions,
which put shadow-fighting and controversy in the place of real
investigation, and led men to think that truth was unattainable.
He therefore enters into conversation, as it were, with the great
minds of former times, and in the spirit of Socrates compels
each of them to yield up his secret, and to acknowledge a supplemental
truth. To this effort he may very probably have been
stimulated by the dialectical activity of his Socratic friends at
Megara, whose logical tastes had drawn them towards Eleaticism.
But, unlike them, while strengthening his metaphysical theory,
he was also led to give to his political speculations a more
practical turn.
The Euthydemus is a treatise “De Sophisticis Elenchis” in the form of a farce, and may serve to introduce the five other dialogues,Euthydemus. as the encounter with Thrasymachus introduces the serious part of the Republic. Under the mask of mockery there is more of concentrated thought, and also more of bitterness, in this dialogue than in the Protagoras or the Gorgias.
A sample of educational dialectic—in which Socrates draws out of young Cleinias the admissions (1) that a philosophy is needed, (2) that the highest philosophy is a science of kingcraft, which remains for the present undefined—is contrasted with a series of ridiculous sophisms, propounded by Dionysodorus and his brother Euthydemus, in which absolute and relative notions, whether affirmative or negative, object and subject, universal and particular, substance and attribute, action and modality, are capriciously confused. Crito, to whom Socrates narrates the scene, is moved to contempt. But Socrates warns him not on this account to despair of philosophy. In conclusion, Isocrates, or some one else, who prematurely mixes up philosophy with practical politics, is cautioned against spoiling two good things.
Such puzzles as—How can I learn either what I know or what I do not know?[1] How can things become what they are not? How is falsehood or denial possible?—although treated jocularly here, will be found returning afterwards to “trouble the mind's eye.”
Plato appears in the same act to have become aware of his affinity with Parmenides, and to have been led to reconsider the foundations of his own doctrine.Parmenides. The one being of Parmenides was a more abstract notion than justice, beauty or the good. And the Zenonian method had more pretension to exactness than the Socratic. But it remained barren, because contented to repeat its own first essays in the destructive analysis of experience, without rising to the examination of its own first principles. For this higher criticism, of which he himself also stood in need, Plato looks up from the disciples to the master Parmenides. The appeal to him is put into the mouth of Socrates, as a very young man, who has framed for himself a theory of ideas, and would gladly see the Zenonian process applied to the notions of sameness, difference, likeness, unlikeness, unity and being.
Parmenides, whom Plato treats with tender reverence not unmixed with irony, proposes to the youth a series of questions which reveal the crudity of the doctrine of εἴδη. (z) Are there ideas of trivial things?[2] (2) How do things “partake” of them? (3) Must not idealism proceed in infinitum? (4) If ideas are thoughts, do they and their participants think? (5) If they are patterns, and things resemble them, must there not be a pattern of the resemblance, and so on in infinitum? (6) If absolute, are they thinkable by man?
These difficulties are real, and yet to deny ideas is to destroy philosophy. (As the paradoxical doubts in the Protagoras do not shake the faith of Socrates in the existence of good, so neither does Plato here intend for a moment to derogate from the belief in the existence of the One and the True.)
Parmenides advises Socrates to arm himself for the further pursuit of truth (1) by the higher application and (2) by the extension or completion of the Zenonian method. (1) The method is to be applied to abstractions. (2) It is not enough to show the inferences which may be drawn from the admission of an hypothesis, but account must also be taken of the inferences which follow from its rejection.
Parmenides exemplifies his suggestion by examining his own first principle in conversation with a youth who, while a contemporary of Socrates, is a namesake of Plato's pupil Aristotle.[3] Not content with the affirmative and negative hypotheses, he pursues either along two lines, according as either term of the proposition is emphasized, and this not only as regards the hypothesis of unity, but also as applied to the alternative hypothesis of plurality. The result, as in the Protagoras, is purely destructive, and the dialogue ends abruptly without a word of reply from Socrates.
The second part of the Parmenides may be regarded as an experiment in which Plato “assays to go” in Eleatic armour. Yet the strange web is “shot” with colours of original thought. The mode of conceiving time and becoming, and the vision of nothingness towards the end, may be noted as especially Platonic. These passages may be regarded in the same light as the wise words of Protagoras or the sober truths which occur amidst the wild fancies of the Cratylus. They should not mislead the interpreter into a search for recondite meanings.
The Zenonian method has been carried out to the utmost in application to the highest subject, and has led the mind into a maze of contradiction.Theaetetus. It remains to call in question the method itself, and the notion of absolute identity and difference on which it hinges, and so to lay anew the foundation-stone of thought. Before this can be attempted, however, another set of difficulties have to be met, and another set of philosophers examined. For the current scepticism had undermined the conception of knowledge as well as that of being, and the fame of Heraclitus was hardly second to that of Parmenides. Protagoras appeared in a former dialogue as the champion of ordinary morality; he is now made the exponent of ordinary thinking. His saying “Man the measure” is shown to rest on the unstable basis of the Heraclitean flux. By an elaborate criticism of both theories knowledge is at last separated from the relativity of sense; but the subsequent attempt to distinguish on abstract grounds between true and false opinion, and to define knowledge as true opinion with a reason (cf. Meno), proves ineffectual. Plato still shows traces of Megarian influence. But the disjunctive method of the Parmenides is not resumed. The indirect proofs are so arranged as to exhibit the skill of Socrates in “bringing to the birth” the germs of thought in a richly endowed and “pregnant” young mind. Theaetetus is the embodiment of the philosophic nature described in Rep. bk. vi., and has already been trained by Theodorus of Cyrene in geometry and the other preparatory sciences of
