The Historical Significance of Plato’s Military Service

In short. What is and is not known about Plato's military service, the wars of his lifetime, and what the guardians of the Republic show about how he thought about soldiers.

The significance of Plato’s military service is smaller, and less certain, than popular accounts suggest. The only direct testimony is Diogenes Laertius (III.8), writing more than five centuries after Plato’s death and citing Aristoxenus, who says Plato fought in three campaigns, at Tanagra, Corinth and Delium, and won a prize for valour at Delium. Delium was fought in 424 BC, when Plato (born c. 428/427 BC) was a small child, so at least part of the report is mistaken, perhaps confused with Socrates, who did fight there. Plato’s own writings never mention military service of his. That an Athenian citizen of his background served at some point during the Peloponnesian War or the Corinthian War is likely, but the specific battles, any rank, and any heroism are uncertain tradition. The war itself, by contrast, is solidly documented, and it is the war, more than the service, that matters historically.

Historical Context of Plato’s Era

Plato was born around 428/427 BC, in the fourth year of the Peloponnesian War between Athens and Sparta and their allies, which ran from 431 to 404 BC. He was therefore a child and a young man during the war, and aged about twenty-three when Athens surrendered. The Thucydidean account of the war lasting twenty-seven years (V.26) is the standard framework. Plato’s adult life then ran through the oligarchy of the Thirty (404–403 BC), the restored democracy, the execution of Socrates in 399 BC, and the Corinthian War (395–387/6 BC), in which Athens fought Sparta again with Thebes, Corinth and Argos as allies. For the wider setting see why Socrates and Plato were important to Greece.

The war plainly formed the political world Plato wrote about. In the Seventh Letter (324b–326b), whose authenticity is debated, he says that the rule of the Thirty and then the democracy’s killing of Socrates led him to conclude that cities would not be well governed until philosophers ruled. Those are claims about political disillusion, and the letter does not describe any battle he took part in. Whether service in the field also coloured his work is a matter of interpretation.

Athens had no professional standing army. Its land forces were made up of citizen hoplites and cavalry, drawn from the propertied classes and mustered by lists when a campaign was called, with the poorest citizens serving in the fleet. Plato’s family was wealthy and aristocratic, so he would have been liable for hoplite or cavalry service from the age of eighteen and for many years after.

Military service was bound up with citizenship and standing, and cavalry in particular was a mark of status. It would be going beyond the evidence to say that Athenians who had not served were socially despised, or that victors were routinely rewarded with land. The formal two-year ephebeia training of eighteen- and nineteen-year-olds is attested for Athens only in the later fourth century BC, after Plato’s death, so it should not be read back into his youth.

Philosophical Contributions of Plato

Plato, renowned for his philosophical insights, made enduring contributions that continue to influence Western thought. His dialogues delved into various aspects of human existence, ethics, metaphysics, and epistemology. Through allegories and dialectic exchanges, Plato explored the nature of reality and the pursuit of knowledge. The “Theory of Forms,” one of his major philosophical ideas, posited that there exist abstract, perfect ideals that shape the material world.

In the Republic (441e–442c) the soul has three parts, reason, spirit and appetite, and justice is each part doing its own work under the rule of reason. In the Phaedrus (246a–254e) the soul’s parts appear in the image of a charioteer driving two horses. Plato uses the spirited part, the home of anger, honour and courage, as the seat of the military virtues. His exploration of justice, virtue and the ideal state in the Republic laid the groundwork for ethical and political philosophy.

Integration of Military Principles in Plato’s Philosophical Teachings

The Republic builds its ideal city around a class of soldiers, so Plato was plainly interested in military life, although we cannot show that this came from experience. The city has three classes: the producers, the auxiliaries, who defend it, and the guardians in the full sense, who rule (412b–414b). The auxiliaries get a demanding education in gymnastics and music, and are compared to well-bred guard dogs, gentle to friends and fierce to enemies (374e–376c). The rulers are drawn from the guardians who prove wisest, and are trained in philosophy as well as in soldiering. Courage is the virtue of the soldier-class, and wisdom the virtue of the rulers.

A reader may find these military principles, discipline, shared hardship and obedience to a command structure, built into Plato’s picture of justice. Whether the picture comes from his own service, from admiration of Sparta, or from the practice of Athenian citizen armies, the texts do not say.

Plato’s Views on War and Peace

In the Republic Plato does not treat war as an end. War arises when a city wants more than it needs (373d–e), and the Republic (466e–471c) sets limits on conduct in war between Greeks: Greeks should not enslave other Greeks or despoil the dead beyond taking their arms, and a conflict between Greek cities is to be treated as a quarrel among kin to be ended in reconciliation, unlike war with non-Greeks. The Laws (I 625e-631a) says more strongly that the lawgiver should aim at peace and the whole of virtue, rather than at courage in war alone. It is fair to say that Plato thinks war should serve the city’s peace and justice.

Examination of Plato’s Beliefs on Military Conflict

Plato does not say that war is only a last resort after diplomacy has failed, and the claim that he is a pacifist is wrong. The ideal city of the Republic keeps a trained military class, and the Laws requires citizens of both sexes to be trained for war and prepared to defend the state. What the dialogues add is the argument that military excellence is not the highest human excellence, and that soldiers need education in virtue so that they do not turn on their own people. In that sense his discussion of the military is about restraint as much as strength.

Why is it important to understand Plato’s military service in the context of his philosophy?
Why was Plato’s military service significant in shaping his philosophical ideas?