The Timpson Lyceum · History of Philosophy (2024)

The Peloponnesian Wars – Lecture 15 (History of Philosophy)

Overview

This lecture bridges the intellectual history of the sophists into the political catastrophe that formed the backdrop of Socrates' Athens: the Peloponnesian Wars between Athens and her allies and Sparta and her allies, chronicled by the Athenian historian Thucydides. The wars take their name from the Peloponnese, the southern peninsula on which Sparta sits. After the Greco-Persian Wars (499–449 BC), Sparta and its Peloponnesian League withdrew to guard the homeland, while Athens organized the Delian League (478 BC) to press the offensive against Persia — a league that gradually hardened into the tributary Athenian Empire. Two rising powers where there had long been one made a collision almost inevitable, and once the pro-Spartan Cimon gave way to the anti-Spartan Pericles, the drift to war became irreversible.

The lecture traces the smaller First Peloponnesian War (c. 460–445 BC), the Thirty Years' Peace (445 BC), and then the Great (Second) Peloponnesian War (431–404 BC): the Periclean strategy of retreating behind the Long Walls, the devastating plague of Athens, the surrender of the Spartans at Sphacteria/Pylos, the fragile Peace of Nicias (421 BC), the disastrous Sicilian Expedition, the machinations of Alcibiades, and the final Spartan naval victory (funded by Persia) that starved Athens into surrender in 404 BC. The aftermath — Spartan hegemony, the rise of Thebes at Leuctra (371 BC), and the eventual conquest of Greece by Philip II and Alexander the Great of Macedon — sets the political stage for Socrates, Plato, and Aristotle.

Key Concepts

• Peloponnesian Wars — Conflicts between Athens (and the Delian League) and Sparta (and the Peloponnesian League), named after the Peloponnese peninsula. A smaller first war (c. 460–445 BC) preceded the Great Peloponnesian War (431–404 BC).
• Thucydides — The Athenian historian whose account is the primary source; the "Athenian" perspective is why the conflict is framed as war against the peoples of the Peloponnese.
• Delian League — Athenian-led alliance (478 BC) to continue the war on Persia. Members contributed ships or money; the treasury was first kept on the island of Delos (hence the name) before Athens moved it home.
• From league to empire — Athens suppressed attempted withdrawals by tearing down city walls (there was no effective siege warfare, so walls otherwise made a city nearly impregnable) and stripping votes. Allies increasingly became tribute-paying subjects — the Athenian Empire.
• Sparta's constraints — A tiny citizen population (roughly 10,000 at its height) and a large enslaved helot class meant Sparta needed quick, decisive campaigns and dreaded prolonged absences or troop losses.
• Naval vs. land asymmetry — Athens' advantages were wealth and a large fleet; Sparta's was a dominant land army. Fleets were expensive: crews vastly outnumbered soldiers (a ~2:1 ratio of sailors to marines/soldiers), and rowers were paid, not citizen-levies.
• Long Walls — After the first war Athens built walls connecting the city to its harbor, the Piraeus, so that its fleet could keep it supplied indefinitely — immune to a Spartan land siege as long as Athens ruled the sea.
• Cimon vs. Pericles — The pro-Spartan Cimon long restrained Athens; his fall and the rise of the anti-Spartan Pericles (c. 461 BC) made war with Sparta all but certain.
• Thirty Years' Peace (445 BC) — Attempted to prevent accidental escalation: neither league was to attack or recruit members of the other; disputes within a league were that league's own affair. It lasted only about 15 years.
• Trigger of the Great War — A chain of proxy disputes (Epidamnus → Corcyra → Corinth) drew Athens into conflict with Corinth, a Spartan ally. Athens' intervention violated the spirit of the peace; pressure from Corinth and others finally pushed Sparta to declare war (432/431 BC).
• Periclean strategy & the plague — Athens withdrew its rural population behind the Long Walls and raided the enemy coast by sea, refusing pitched land battle. Overcrowding bred a plague (430–429 BC) that killed a large fraction of the population — roughly a quarter to a third — and took Pericles himself.
• Sphacteria / Pylos (425 BC) — Athens trapped and captured 292 Spartans, an almost unheard-of surrender that was a severe blow given Sparta's tiny citizen body, and yielded prized hostages.
• Peace of Nicias (421 BC) — A treaty (exchange of cities and prisoners; Spartan recognition of the Athenian Empire) that never truly held, because subject cities and Thebes refused to honor the exchanges.
• Alcibiades — Charismatic, ambitious, well-connected Athenian (raised in Pericles' house) who championed the Sicilian Expedition, then defected to Sparta (revealing Athens' plans), later to Persia, and finally back to Athens — a serial turncoat eventually assassinated.
• Sicilian Expedition (415–413 BC) — Athens' overreach: an enormous fleet and army sent to take Syracuse. Crippled by Alcibiades' recall (over the mutilation of the Herms), his defection, and a cautious replacement commander, it ended in total destruction of the expeditionary force.
• Persian gold & Lysander — Persia funded a Spartan fleet (manned with paid crews and Syracusan ships); the able Spartan admiral Lysander finally won naval supremacy, blockaded the Piraeus, and starved Athens into surrender in 404 BC.
• Aftermath — Sparta imposed the Thirty Tyrants (soon overthrown; the restored democracy later condemned Socrates), then squandered its hegemony; Thebes shattered Spartan invincibility at Leuctra (371 BC), before Philip II and Alexander the Great of Macedon subdued all of Greece by 338–331 BC.

Worked Example

Why "the strong do what they can, and the weak suffer what they must." The Melian Dialogue (416 BC) is the war's sharpest statement of the "might makes right" logic met earlier in Thrasymachus. Athens demands that neutral Melos submit and pay tribute; the Melians, hoping for Spartan rescue, resist — and are besieged, their men executed and their women and children enslaved. The episode is naturally modeled as a two-player game. Let the payoff pairs be written $(\text{Athens},\ \text{Melos})$, on an ordinal scale where larger is better.

1. Athens has a dominant strategy. Compare Athens' payoffs column by column. If Melos submits, $3 > 2$ (Coerce beats Relent). If Melos resists, $1 > 0$ (Coerce beats Relent). Since $\text{Coerce}$ pays more in every column, it strictly dominates — Athens presses its demand regardless of what Melos does. This is the game-theoretic content of "the strong do what they can."
2. Melos best-responds to Coerce. Given Athens will Coerce, Melos compares its own top-row payoffs: submitting yields $-3$, resisting yields $-100$. Since $-3 > -100$, the rational reply is to submit — "the weak suffer what they must."
3. Unique equilibrium. The strategy profile $(\text{Coerce},\ \text{Submit})$ is the only Nash equilibrium: neither side can improve by a unilateral change ($3 \ge 1$ for Athens; $-3 \ge -100$ for Melos).
4. Modeling the Melians' actual gamble. The historical Melians resisted because they weighted a slim hope of Spartan aid. Let $p$ be the probability Sparta arrives and rescues them. Then the expected value of resisting is

1. The break-even probability. Resistance only beats submission ($-3$) when $\mathbb{E}[\text{Resist}] > -3$:

1. The tragic verdict. Rescue would have required better than an 88% chance of Spartan intervention — wildly optimistic for a distant island Sparta had every incentive to ignore. With realistic $p \approx 0.1$, $\mathbb{E}[\text{Resist}] = 110(0.1) - 100 = -89 \ll -3$. Submission was overwhelmingly the rational choice; Melos hoped instead of calculated, and paid the maximal price. $\blacksquare$

Summary

• The Peloponnesian Wars pitted the naval, wealthy Athenian Empire (grown out of the Delian League) against the land power of Sparta and the Peloponnesian League, with two rising hegemons making conflict nearly unavoidable.
• Athens' Long Walls and sea supremacy versus Sparta's land army produced a war of attrition in which neither side could force a decisive result — until external shocks broke the stalemate.
• The plague (killing roughly a quarter to a third of Athenians, including Pericles), the capture of 292 Spartans at Sphacteria, and the failed Peace of Nicias mark the grinding middle of the war.
• The catastrophic Sicilian Expedition, the treacheries of Alcibiades, and finally Persian-funded Spartan sea power under Lysander starved Athens into surrender in 404 BC.
• The victory bred a resented Spartan hegemony, overturned by Thebes at Leuctra (371 BC) and ultimately by Macedon under Philip II and Alexander the Great — the political world into which Socrates, Plato, and Aristotle were born.