Plato

Plato shaped Western philosophy's headwaters and has influenced thought for over 2,400 years. Born around 427 BC into Athenian aristocracy, his real name was Aristocles; Plato was a wrestling nickname. He was athletic enough to compete at the Isthmian Games and once considered politics.

Meeting Socrates around age 20 changed everything. When Athens sentenced Socrates to death in 399 BC for impiety, the 28-year-old Plato gained both a distrust of democracy and a need to define justice.

He then traveled to Egypt and southern Italy, absorbing Pythagorean mathematics and Parmenidean ontology. Around 387 BC he founded the Academy outside Athens, often called the West's first higher-learning institution; it lasted roughly nine centuries.

The Theory of Forms is Plato's core idea. Every beautiful object, he argued, participates in an eternal Form of Beauty. Particulars change; Forms do not. The Cave allegory in Republic VII captures the point: prisoners mistake wall shadows for reality, as people mistake sense data for truth.

In politics, the Republic argues that a wise philosopher should rule, a retort to the mob justice that killed Socrates. Plato tried to implement this at the court of Dionysius in Syracuse, failed, and was nearly sold into slavery.

His works are dialogues with Socrates as lead speaker, reflecting the belief that truth emerges through inquiry, not lecture. He died c. 347 BC. Aristotle critiqued and extended his legacy; Neoplatonism carried his ideas into Christian, Jewish, and Islamic thought.