1. Plato
and the Republic

2. History of Philosophy in Brief 5th Century BC & Peloponnesian War
“Good guys” = The Sophists
Heraclitus – “all is in flux”
Protagoras – values are relative; advised Pericles
Gorgias – in praise of Helen
Antiphon – rhetorician; leader of oligarchic coup
Thrasymachus – justice is interest of the stronger
- taught philosophy as a technical skill
Bad guy = Socrates
- taught philosophy as a way of life
Result: Followers of “Good guys” kill “bad guy” (Socrates)

3. History of Greek Philosophy, 5th Century BC
Sophist Socrates

4. Teachings of the sophists relevant to the Republic
1. Everything is in flux (Heraclitus).
2. “Justice is nothing other than the interest of the stronger” (Thuc., Hist.; Thrasymachus, Rep. I)
3. “Man is the measure of all things” (Protagoras), i.e., values not real, but relative and a matter of opinion.
4. A cynical view of human nature.
5. Sophists taught “how to make the weaker argument the stronger,” i.e., philosophy is a technical skill that helps you in your career, for example, as a lawyer.

5. Students of Sophists relevant to Republic
Thucydides ( BC)
student of Antiphon
put Sophistic reasoning in mouths of Athenians & Spartans in “Melian Dialogue” (v.89) & “End of Platea”
“Justice depends on the balance of power. In fact the stronger can do whatever they have the power to do, and the weak must accept whatever the stronger does” (Melian dialogue)
Melian Dialogue presents Thrasymachus’ teaching on justice 20 years before Republic

6. Students of Sophists relevant to Republic (cont.)
Thucydides represents Athenians & Spartans negatively by associating them with Sophistic teaching
But Thucydides also expresses Sophistic cynicism:
“Human nature…showed itself…as something incapable of controlling passion, insubordinate to the idea of justice, the enemy to anything superior to itself” (“Civil War in Corcyra,” iii.84).
Thuc. a kind of ancient Hobbes, regarded virtue as unattainable or illusory.

7. Students of Sophists relevant to Republic (cont.)
Thucydides’ cynicism about human nature is a pessimistic conclusion drawn from the Peloponnesian War, which devastated Greece and reduced many to barbarism.
Whether we regard Thucydides a Sophist is unimportant. What is important for Plato is that he expressed such cynicism about human nature

8. Influence of Sophists declines
History of Philosophy in Brief 4th Century BC & Aftermath of Peloponnesian War
Influence of Sophists declines
Influence of Socrates’ students, Plato & Aristotle rises
Plato writes dialogues criticizing Sophists, e.g., Republic
Now, Socrates = The good guy
Sophists = The bad guys

9. History of Greek Philosophy, 4th Century BC
Socrates Sophist

10. Socrates Taught philosophy as a way of life
“The unexamined life is not worth living.”

11. Plato’s goals To refute and destroy reputation of Sophists
To refute cynicism about human nature expressed by Thrasymachus & Thucydides
To advance optimistic model of human nature
In difficult times, we can rely on human dignity and act justly despite how others may be behaving

12. Soul as chariot (discussed in Plato, Phaedrus)

13. Clytemnestra kills Cassandra (scene from the Agamemnon of Aeschylus)

14. Scene from Verdi’s La Traviata

15. Sign at entrance of Academy

16. Fig. 1: The Platonic Solids

17. Role of study of geometry & mathematics
1) It transfers us from the material to the intellectual, and so frees us from domination of appetites and emotions.
2) It proves that even human reason is non-arbitrary, not relative, so that justice, for Plato, becomes a constructible, almost geometrical concept.

18. Fig. 3: Plato’s Model of the Soul

19. Fig. 4: Plato’s Model of the Guardian State

20. Ostracism
Ostracon recording vote to exile Themistocles