Aristotle

Aristotle designed Western scholarship's template virtually alone. Born in 384 BC in Stagira, son of the Macedonian court physician Nicomachus, he absorbed the medical habits of observation and classification that became his empiricist foundation.

At 17 he entered Plato's Academy and stayed 20 years. A core divergence emerged: Plato placed true reality in transcendent Forms; Aristotle held that essence resides in individual things. The later saying, "Plato is dear to me, but dearer still is truth," captures his respectful independence.

After Plato's death in 347 BC he left Athens. On Lesbos he dissected marine creatures and classified over 500 species, the ancient world's most systematic biological survey. Around 343 BC Philip II asked him to tutor the 13-year-old Alexander.

Back in Athens by 335 BC, he founded the Lyceum. He created formal logic through the syllogism, the first explicit framework for deduction. The Nicomachean Ethics centered virtue on the mean: courage sits between recklessness and cowardice. This character-based ethics differs from rule-based and outcome-based alternatives.

The Politics defined humans as political animals, insisting individual and communal good are inseparable. His Metaphysics, with matter-form theory and four causes, was absorbed by Aquinas into Christian philosophy. Anti-Macedonian sentiment drove him from Athens after Alexander's death; he reportedly vowed to prevent Athens from sinning against philosophy twice. He died in 322 BC at 62. Translated into Arabic, his works returned to medieval Europe and set the stage for modern science.