Plato
Socrates' student and the West's most influential philosopher, who founded the Academy and designed rule by philosopher-kings in The Republic.
Plato is the philosopher every later philosopher argues with. Born into the Athenian aristocracy around 428 BC, he watched the democracy he distrusted execute his teacher Socrates, and he spent the rest of his life trying to design a world where that could not happen: a just society ruled by knowledge rather than by the shifting appetites of the mob. His answer, the rule of philosopher-kings, has inspired and unsettled political thinkers for 2,400 years. The 20th-century philosopher Alfred North Whitehead called the entire European tradition "a series of footnotes to Plato," and he was not really exaggerating.
The Academy and the Forms
Around 387 BC Plato founded a school in a grove outside Athens sacred to the hero Academus. This Academy, which ran in some form for nearly 900 years, is the ancestor of the university and the source of the word "academic." There Plato developed his most famous idea, the theory of Forms. The chairs, circles, and just acts we see in the physical world, he argued, are imperfect copies of perfect, eternal templates, the Forms, which exist beyond the senses and can be grasped only by reason. In the Allegory of the Cave he pictures ordinary people as prisoners chained in the dark, mistaking shadows on the wall for reality, while the philosopher is the one who escapes into the sunlight and sees things as they truly are. Knowledge, for Plato, means turning away from appearances toward that hidden order.
The Republic
Plato's boldest book, The Republic, applies this conviction to politics. If most people mistake shadows for reality, he reasoned, then letting them vote on how to run a state is like letting untrained passengers steer a ship. The just city should instead be ruled by those who have seen the truth: philosopher-kings, an elite trained for decades in mathematics and philosophy, who own no private property, keep no private families, and rule not for their own benefit but because they alone know what the good actually is. Below them stand guardian soldiers, and below those the producers. It is a vision of order, wisdom, and expertise placed permanently above popular opinion.
Seductive and dangerous
That vision has never stopped appealing to people who look at democracy and see chaos, and it has never stopped alarming people who prize freedom. In 1945, writing in the shadow of Hitler and Stalin, the philosopher Karl Popper attacked The Republic in The Open Society and Its Enemies as an early blueprint for totalitarianism: a rigid caste system, censorship of art and poetry, state-managed breeding, and a ruling class answerable to no one. Defenders reply that Popper read a 20th-century nightmare back into a 4th-century thought experiment, and that Plato was diagnosing the failures of democracy rather than drafting a police state. The argument stays unresolved because it is really an argument about us: whether wisdom or consent should hold ultimate authority.
The footnote that swallowed the tradition
Plato's reach is hard to overstate. He wrote philosophy as drama, in dialogues where Socrates questions his way toward truth, and in doing so set the agenda for metaphysics, ethics, politics, and theology for two millennia. Christian theologians borrowed his eternal Forms, the Renaissance rediscovered him, and every modern quarrel about elites versus the people, or expertise versus democracy, still runs along channels he dug. When Whitehead called the tradition a footnote to Plato, he meant that the big questions were largely posed by the time Plato finished asking them. We are all, still, arguing with the man from the Academy.