By the fifth century BCE, Athens had become a democracy and an imperial power. In a city where citizens debated in the Assembly and argued their own cases in court, the ability to speak persuasively was valuable. Into this market came the Sophists, traveling teachers who taught rhetoric and the skills of public life for a fee.

The Sophists

The best known was Protagoras of Abdera, who famously said that “man is the measure of all things.” This is often read as a kind of relativism: what seems true to me is true for me. Gorgias of Leontini was a celebrated speaker who praised the almost magical power of words. Sophists also raised a lasting debate between nomos (custom or convention) and physis (nature): are justice and morality natural, or merely human agreements?

The Sophists have had a poor reputation, largely because our main source is Plato, who disliked them. To be fair, they were serious thinkers who spread education, questioned inherited beliefs and took democratic debate seriously. Plato's charge was that they taught people to win arguments rather than find the truth, and that they charged money for it.

Socrates

Socrates (about 469 to 399 BCE) was an Athenian stonemason's son who spent his life in conversation in the marketplace. He wrote nothing. We know him through the dialogues of his student Plato, the memoirs of Xenophon, and a mocking portrait in Aristophanes' comedy The Clouds. Separating the historical Socrates from the character in Plato is one of the oldest puzzles in philosophy.

Socrates' friend Chaerephon once asked the oracle at Delphi whether anyone was wiser than Socrates, and the answer was no. Puzzled, Socrates questioned politicians, poets and craftsmen, and concluded that his only wisdom was this: he knew that he did not know, while others wrongly believed they did. This is often called Socratic ignorance.

The elenchus

His method is called the elenchus, a Greek word meaning cross-examination or refutation. Socrates would ask someone to define a virtue, such as courage or piety. He then asked further questions until the person's answers contradicted one another, showing that the definition failed. Many dialogues end in aporia, a state of puzzlement with no agreed answer. The goal was not humiliation but clearing away false confidence, so the real search could begin. Socrates compared himself to a midwife who helps others give birth to ideas, and to a gadfly stinging a large, sluggish horse (Athens) into life.

Socrates also held some striking views. He argued that no one does wrong willingly: people do wrong because they mistake what is good for them, so virtue is a kind of knowledge. He thought caring for one's soul mattered more than wealth or reputation.

The trial and death

In 399 BCE Socrates was tried before a jury of about 500 citizens. The charges were impiety (not recognizing the city's gods and introducing new divinities) and corrupting the young. Background politics mattered: Athens had recently lost the long Peloponnesian War, and some of Socrates' associates, such as Critias, had been among the Thirty Tyrants who briefly overthrew the democracy. Plato's Apology presents his defense speech, in which he says, in Jowett's translation, that “the unexamined life is not worth living.”

He was convicted and sentenced to death. In the Crito, friends offer to help him escape, but he refuses, arguing that he must not break the laws of the city that raised him. In the Phaedo, he drinks hemlock calmly among his friends. His death made him a model of the philosopher who will not give up the search for truth, even at the cost of his life.

Worked example: a short elenchus

Here is an invented conversation in the style of Plato's early dialogues. Socrates meets a young man, Lysander, who has just won a prize for courage.

Socrates: You must know what courage is, then. What is it?

Lysander: Courage is standing your ground in battle and not running away.

Socrates: But are cavalry who retreat and wheel about to attack again cowards? And is a person who faces illness or poverty bravely not courageous, though there is no battle?

Lysander: They are courageous. Let me say instead: courage is endurance of the soul.

Socrates: Is all endurance fine and good? Suppose someone foolishly endures, refusing to leave a burning house to save his lute. Is that courage?

Lysander: No, that is foolish.

Socrates: So courage is wise endurance? But then what kind of wisdom is it? Knowledge of what is truly to be feared?

Lysander: I suppose so. But now I am not sure that I know what courage is at all.

This short exchange (loosely modeled on Plato's Laches) shows the elenchus at work. Each definition is tested against examples and against Lysander's other beliefs until a contradiction appears. The conversation ends in aporia, puzzlement. Yet Lysander has gained something: he has moved from a confident but narrow definition to a better question. This is why Socrates thought exposing ignorance was the start of wisdom, and also why many powerful Athenians found him exasperating.