Chapter 2 · First part

⟨On Dialectic⟩⁵¹

Plato from the Republic

Does not the dialectical method alone proceed in this way, doing away with hypotheses as it advances toward the first principle itself, to establish itself securely? It gently draws the eye of the soul, truly buried in a kind of barbarous mud, and leads it upward, using the arts we have discussed as fellow workers and helpers in turning it around.⁵² We have often called these arts sciences out of habit, but they need another name, for something more effective than opinion and less clear than knowledge. Earlier, at any rate, we defined it somewhere as “discursive thought.”⁵³

In the same work

“Then does it seem to you,” I said, “that dialectic lies above our studies like a coping stone, that no further study could rightly be placed above it, and that our course of studies has now reached its completion?”⁵⁴

Plato from the Phaedrus · 1

“Two procedures happened to be mentioned in what we said. It would be no unpleasing thing if someone could grasp their power as an art.”

“What two?”

“To bring things scattered in many places into a single form by seeing them together, so that, by defining each subject, one may make clear whatever one wishes to teach. Take what was just said about Love, when it was defined as to what it is, whether the account was good or bad. At any rate, this enabled the discourse to express itself clearly and consistently.”⁵⁵

Plato from the Phaedrus · 2

“And what is the other procedure you mean, Socrates?”

“The ability, in turn, to divide according to forms, at the joints where they naturally lie, without trying to break any part as a bad butcher would. Our two speeches just now took the irrational element in thought as one common form. Just as in a body paired parts with the same names grow from a single whole, some called left and others right, so the two speeches treated drunken frenzy as a form naturally present in us.⁵⁶ The one cut off the part on the left and divided it again, never stopping until it discovered among those divisions a love called left-handed, which it reproached with every justice. The other led us to the right-hand part of madness, discovered a love bearing the same name as the first but divine in character, held it before us, and praised it as the cause of our greatest blessings.”⁵⁷

Plato from the Phaedrus · 3

“What you say is entirely true.”

“I myself am a lover of these divisions and collections, Phaedrus, so that I may be able to speak and think. And if I judge someone else naturally able to look toward a unity and toward a plurality, I follow behind him, in his footsteps, as though he were a god.⁵⁸ As for those who can do this, whether the name I give them is right or wrong, a god knows; at any rate, so far I call them dialecticians.”

Archytas from On Being · 1

Those who say that two statements can be made about everything, opposed to one another and both true, seem to me entirely mistaken. First, I hold it impossible for them to be opposed to one another while both are trustworthy—as though the beautiful were opposed to the beautiful, and the white to the white. That is not how it is: the beautiful and the ugly are opposites, as are the white and the black. Likewise, we say, truth is opposed to falsehood. Two true statements cannot be made ⟨in opposition⟩, nor two false ones: one must be true, the other false.⁵⁹

Archytas from On Being · 2

For someone who praises a person’s soul and ⟨someone⟩ who finds fault with the body are not speaking about the same thing—unless speaking about the earth and the heavens would also concern the same thing. These are two things, not one. I wish to show this also by naming a particular case. Someone who says that the Athenians are good men in matters of speech, and someone who says that they are poor in matters of gratitude, are not making opposed statements. For opposites stand opposed to one another concerning the same matter, whereas these are two different matters.⁶⁰

From Iamblichus’s Letter to Dexippus on Dialectic · 1

It truly was a god who revealed dialectic and sent it down to human beings: according to some, Hermes, lord of eloquence, who carries in his hands its emblem of serpents looking toward one another.⁶¹ But the most approved and eminent among philosophers maintain that Calliope, the eldest of the Muses, bestowed the unfailing and irrefutable assurance of discourse, distinguished by “gentle reverence.”⁶²

Iamblichus to Dexippus · 2

As the deeds themselves show, the god at Delphi, neither declaring nor concealing, as Heraclitus says, but giving signs through his oracles, rouses their hearers to dialectical investigation. Through it, ambiguity and sameness of name have been sorted out, and every double meaning, when investigated, has kindled the light of knowledge. Themistocles too understood this well: by skillfully investigating the “wooden wall,” he became indisputably responsible for the Greeks’ deliverance.⁶³ The god at Branchidae likewise displays related works of dialectic, making induction quite evident when he says: “Neither a swift-flying arrow, nor a lyre, nor a ship, nor anything else could ever be useful without knowledgeable use.”⁶⁴

From Iamblichus’s Letter to Sopater on Dialectic · 1

All human beings engage in discussion. They possess this capacity innately from youth and share in it to some degree, some more, some less. We must in no way surrender this gift of the gods; rather, it deserves to be strengthened through practice, experience, and systematic skill.⁶⁵ Observe how exceptionally useful it remains throughout life: in our encounters, it converses with people on the basis of common conceptions and opinions; in the discovery of the arts, it finds their first principles; before actions, it reasons about how they should be performed; and through preliminary training it supplies wonderfully effective methods for the philosophical sciences.

Iamblichus to Sopater · 2

If we should also consider what is prior to these uses, no part of philosophy comes into being without dialectical reasoning. Even if we discover some doctrine about nature, we establish it by reasoning; and whatever we investigate concerning the gods, dialectical argument helps to establish it. In general, we can neither say nor hear anything once we dispense with this method. Even the claim that dialectic is not to be taught must itself be learned by arguing dialectically.⁶⁶