Classical. The Sophists made rhetoric a subject that could be taught. They also made it controversial. Athens' greatest philosopher, Plato, attacked rhetoric as dangerous flattery, while his rival Isocrates founded a school that defended it as the heart of a good education. Their argument still shapes how we think about persuasion.

Gorgias and the power of speech

Gorgias left a short showpiece called the Encomium of Helen, a praise of Helen of Troy, whose elopement with Paris was blamed for the Trojan War. Gorgias set out to defend her, arguing that she must have gone either by the will of the gods, by force, by love, or because she was persuaded by speech, and in no case was she to blame. In the passage on persuasion, he declares that speech is a mighty lord, which with the smallest and least visible body accomplishes the most divine works: it can stop fear, remove grief, create joy and increase pity. He compares the effect of words on the soul to the effect of drugs on the body. At the end he calls the speech his plaything, a game. It was both a demonstration of skill and a theory of rhetoric's power.

Dissoi Logoi

A short anonymous text from around 400 BCE, known as the Dissoi Logoi, “Double Arguments,” shows the Sophists' method in action. It argues both sides of questions such as whether good and bad are the same, whether justice and injustice are the same, and whether wisdom can be taught. For each, it first presents the case for one view, then the case against. Arguing both sides was a central training method, meant to sharpen the mind and prepare a speaker for whatever his opponent might say.

Plato's attack

Plato saw great danger in this. In his dialogue Gorgias, Socrates questions Gorgias and his followers and argues that rhetoric as they practice it is not an art at all but a knack, a form of flattery. It aims at pleasure, not at truth or the good. Socrates compares it to cookery: as cookery pretends to be medicine, offering pleasant food rather than healthy treatment, so rhetoric pretends to be justice, offering pleasant speeches rather than what is truly good for the soul. A rhetorician, Socrates argues, can persuade an ignorant crowd better than an expert can, precisely because the crowd cannot tell knowledge from its imitation.

In the Phaedrus, Plato offers a more hopeful picture. A true art of rhetoric is possible, he suggests, but only for someone who knows the truth about the subject, understands the different kinds of human souls, and knows which kinds of speech move which kinds of soul. Rhetoric, rightly practiced, would be a way of leading souls toward truth.

Isocrates' answer

Isocrates (436 to 338 BCE) took a different view. Born into a wealthy Athenian family that lost its fortune in the Peloponnesian War, he began as a speechwriter and around the 390s opened one of the most successful schools in Greece. He had a weak voice and a nervous temperament, so he rarely spoke in public; instead he wrote speeches meant to be read and circulated, on the great political questions of the day.

In a pamphlet called Against the Sophists, Isocrates attacked teachers who promised too much. Natural ability came first, he said, then practice, and only then instruction; no teacher could turn a dull student into a great speaker. He called his own teaching philosophia, a word he used for a practical wisdom developed through studying and composing speeches on important public matters. He believed that learning to speak well and learning to think well were the same discipline, and that a man who spoke on noble subjects would become nobler himself. He charged substantial fees, reportedly a thousand drachmas for a full course, and his students included generals, statesmen and historians.

Kairos

Both Gorgias and Isocrates stressed kairos, a word meaning the right or opportune moment. A speech that would succeed at one moment might fail at another; what to say, and when, depended on the occasion, the audience and the mood of the moment. Kairos could not be reduced to rules. It had to be learned through experience and judgment, which is one reason Isocrates thought natural talent and practice mattered more than handbooks.

Worked example: argue both sides

Here is an exercise in the manner of the Dissoi Logoi. The question: Is it ever right to deceive?

• First argument, yes: A doctor who tells a frightened patient that a bitter medicine is sweet deceives him, yet does him good. A general who tricks the enemy saves his own city. A parent who hides danger from a small child protects her. Deception, then, is sometimes right.
• Second argument, no: Every deceiver claims to deceive for the other's good, and so the tyrant excuses himself as easily as the doctor. If we permit deception whenever someone thinks it helpful, no one can trust any word. Trust is the foundation of the city; therefore deception destroys what it claims to protect.

Compose both sides yourself before deciding which you believe. This was how Greek students trained. Plato would ask the next question: once you can argue both sides, how do you find out which is true? The tension between the Sophists' skill and Plato's demand for truth runs through all rhetoric. A good speaker needs both: the ability to see every side, and the honesty to defend the side that is right.