Cambridge philosopher Iain King begins a new series looking at how great thinkers were shaped by war. He begins with Socrates, the 5th century Athenian intellectual considered the founder of Western philosophy.

Socrates was once a soldier, and his military experiences certainly shaped his revolutionary approach to philosophy. But finding the truth about Socrates’ service record is not easy. Despite being one of the most influential philosophers ever, everything we know about the man comes from just three sources: a satirist, a military historian, and one of Socrates’ own pupils. They offer wildly different accounts.

Aristophanes wrote satirical plays, and his 423 BC comedy The Clouds ridicules Socrates. Instead of describing Socrates service as an infantryman, Aristophanes makes Socrates out to be unpatriotic. The insulting caricature may even have helped persuade jurors to sentence Socrates to death 24 years later.

The second source is Xenophon, a practical-minded soldier-historian, with a military focus. Xenophon is more sympathetic to Socrates, and largely corroborates the third source: Plato. It is Plato – a student of Socrates who went on to became a prominent philosopher himself – who tells us most about Socrates’ courage in the Athenian front-line.

Socrates had two years’ military training in his early twenties. He would have become familiar with fighting as part of a phalanx, and been trained to fight with a spear. As a heavy infantryman, a hoplite, Socrates would have been protected by a shield and body armour which could have weighed up to 30kg, although equipment varied from soldier to soldier. Like other young Athenian servicemen, Socrates probably had some short peacetime deployments to the borders of Athenian territory, but spent most of his time in Athens itself.

Active service

Socrates’ first proper engagement was at Potidaea in 432 BC – a city-state threatening to break away from Athens. Already aged 37, Socrates played a role in the initial battle, and also in the subsequent siege of the city. The campaign kept him away from Athens for almost three years, and it was on the way home, as part of a victorious army, that Socrates distinguished himself.

The Athenian army was ambushed near Spartolos and suffered serious losses. Socrates, though, saved the life and armour of Alcibiades, a man who went on to become one of Athens’ leading strategists and politicians.

Five years after his return from Potidaea, with the first phase of the Peloponnesian Wars at its height, Socrates fought at the Battle of Delium. The battle, in 424 BC, provides the first recorded incident of fratricide – or what might now be called ‘friendly fire’ casualties – when confused hoplites began fighting each other, unable to distinguish fellow Athenians from their enemies, the Boeotians.

After some early successes, the Athenians were routed. Socrates, though, seems to have maintained some order in his retreat. Plato wrote ‘when you behave in war as he did, then (the enemy) do not even touch you; instead they pursue those who turn in headlong flight’.

The Athenian general Laches was even more generous: ‘If all the Athenians had fought as bravely as Socrates, the Boeotians would have erected no (victory) statues.’

Socrates’ last military service was at Amphipolis. Approaching 48 by then, his role in the battle is unclear. Spartan victory at Amphipolis soon led to an armistice with Athens, and the first phase of the war was over.

War on the mind

Did fighting in the front-line influence Socrates’ ideas? Socrates’ service record certainly makes him seem brave, perhaps even reckless, and the same boldness is clear in his philosophy: he showed great courage taking on Athens’ authority figures and received wisdom.

Socrates’ philosophy may also have been inspired by the ideals of Athens. Stirred by rhetoric about free expression and democracy on the battlefield, Socrates proved a pugnacious controversialist on the home front – even though it caused great offence to some of Athens’ citizens.

Could Socrates have been suffering from post-traumatic stress disorder (PTSD)? He is often described as ‘wide-eyed’, but other evidence for this suggestion is slim. Plato suggests Socrates was interested in radical ideas before he went to war. Although it is possible, it is hard to attribute Socrates’ ‘strangeness’ to his experience of combat. There is much reason to think that it is the exceptional stress of modern industrialised warfare that is responsible for the epidemic of PTSD among soldiers over the last century.

The clearest impact of Socrates’ wartime service on his thinking was surely the way in which he approached death. During his trial, he used his military record to prove his patriotism. He demonstrated his loyalty to the ideals of Athens by refusing to evade the death penalty it bestowed on him. Finally, by drinking the hemlock, Socrates proved his fearlessness. The soldier-philosopher had become a martyr, securing his fame and influence, which lasts to this day.

The Peloponnesian War (431-404 BC)

From a 21st century viewpoint, the Peloponnesian War may seem like a civil conflict: a long-running feud between different parts of Greece. But it spread far beyond the borders of modern Greece: there was action in Sicily, the Dardenelles, and Cyprus; and the stakes were much higher – for some, it was about nothing less than the survival of civilisation itself.

On one side, Athens, the world’s greatest naval power, saw itself fighting for democracy and to defend the flourishing of culture that was Greece’s ‘golden age’. On the opposing side was Sparta, an austere military regime with a grim view of human life (they left their weaker babies to die on mountain tops), supported, in the final phase of the war, by the Persian Empire; a super-power which had only recently tried to subjugate the West.

The Peloponnesian War broke out when city-states once allied with Athens in self-defence against the Persians tried to assert their autonomy. The Athenian Empire struck back, besieging Potidaea in 432BC, where Socrates first saw action.

A decade of skirmishing, raids, and temporary occupations followed. Rather than face the crack infantry of Sparta in an open land battle, Athens concentrated on maritime operations. The city suffered more from a great plague which halved its manpower in 430 BC than from any military attack.

A fragile truce held from 421 BC to 415 BC, when Athens came to the defence of allies in Sicily who were under siege by Syracuse, an ally of Sparta. Athens’ expeditionary force was destroyed, making Athens itself vulnerable.

But they held off the assaults, knocking out the Spartan fleet at the Battle of Cyzicus in 410 BC, and winning further victories until 406 BC. Then Sparta, under inspired leadership from Lysander, and with a new navy funded by the Persians, attacked Athens’ grain supply in the Hellespont (the Dardenelles).

The Athenian fleet was lured into a trap and captured. Lysander followed up with actions along the coast that forced the surrender of Athenian allies whom Athens could no longer protect. Deprived of both grain and ships, Athens itself surrendered in March 404 BC. Athen’s walls were destroyed, the city was humbled, and Sparta had become the new master of Greece.

Socrates: martyr of Western philosophy

Socrates is one of the world’s most famous philosophers, and for good reason: he revolutionised our approach to ideas.

Earlier thinkers – known as ‘Pre-Socratic’ philosophers – had really just made suggestions. They pondered whether all matter was made of particles, thought about the importance of time, and wondered whether knowledge was just a matter of opinion. Some made advances in mathematics, or used paradoxes to show that the world was not as it seemed.

Socrates’ genius was not to suggest new ideas, but to challenge conventional ones. Socrates would quiz people in the market-place to see whether their beliefs held true; usually they did not. Socrates phrased his questions to make them sound silly, even infantile, while in fact he was exposing the stupidity of the person he was questioning.

Many felt embarrassed after being interrogated by Socrates – a strange, unwashed, pug-nosed man. He was the ancient equivalent of a disrespectful journalist asking direct questions to a politician. Indeed, the whole process of using questions and follow-up questions to get to the truth, a style which dominates modern teaching, is an approach started by Socrates.

Socrates applied his ‘method’ to all sorts of cherished beliefs, including courage, wealth, and wisdom. It was a process of dialogue and discovery, sometimes teasing participants, but also enlisting them in pursuit of the truth.

Socrates concluded many things, including that virtue could not be taught, extra riches would not bring extra happiness, and that the only real knowledge was that we know nothing.

Exposing the ignorance of authority figures became dangerous, especially as Athens suffered political turmoil after its defeat by Sparta. Socrates’ enemies put him on trial for ‘irreverence’ to the gods and misleading the youth of the city, and he was sentenced to death.

The ageing philosopher, now 70 years old, could have escaped. Indeed, most of his enemies assumed, even hoped, that he would. But Socrates took hemlock. Death allowed him to stay true to his philosophy, and to immortalise his ‘Socratic method’.