Aristotle
The philosopher who systematized logic, ethics, politics, biology, and metaphysics. Perhaps the most influential thinker in Western history.
Aristotle (384-322 BCE) was not just a philosopher but the first true systematizer of knowledge. Where Plato sought truth in abstract Forms, Aristotle insisted on empirical observation — he dissected animals, catalogued constitutions, analyzed plays. His logic (the syllogism) remained the foundation of rational thought for two millennia. His Nicomachean Ethics introduced eudaimonia (flourishing) as the goal of life, achieved through virtue as a mean between extremes. His Physics gave us teleological causation — every natural thing has a purpose (telos). His Metaphysics asked what it means for something to exist. His Categories gave us the first ontology — the classification of all that is. The breadth is staggering: logic, ethics, politics, poetics, physics, biology, metaphysics, rhetoric. Modern knowledge graphs owe something to his original impulse: to organize all of knowledge into a coherent system.
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Sub-topics
Aristotle's framework for explaining why anything exists: material, formal, efficient, and final causes. A complete explanation requires all four.
Morality is not about rules or consequences, but about character. Virtue is a habit — the golden mean between excess and deficiency.