Key Greek Philosophers

Why This Matters

Greek philosophy isn't just a list of old names and abstract ideas—it's the foundation of nearly every intellectual tradition you'll encounter in Western thought. When you study these thinkers, you're tracing the origins of ethics, metaphysics, epistemology, natural science, and political theory. The exam will test whether you understand how these philosophers responded to each other, built competing systems, and shaped the intellectual landscape of the ancient Mediterranean world.

Don't just memorize who said what. Focus on the philosophical problems each thinker was trying to solve and how their answers differed. You're being tested on your ability to connect ideas across thinkers—to explain why Parmenides and Heraclitus represent opposing views on reality, or how Epicureans and Stoics offered competing paths to the good life. Master the relationships between these philosophers, and you'll be ready for any comparative question the exam throws at you.

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The Foundational Trio: Socrates, Plato, and Aristotle

These three thinkers form the backbone of classical philosophy, each building on—and sometimes rejecting—his teacher's ideas. Their intellectual lineage (Socrates taught Plato, Plato taught Aristotle) represents the most influential philosophical succession in Western history.

Socrates

• Father of Western philosophy—never wrote anything himself; we know him through Plato's dialogues and Xenophon's accounts
• The Socratic method uses cooperative questioning to expose contradictions in beliefs and stimulate critical thinking
• "The unexamined life is not worth living"—his trial and execution for "corrupting the youth" became a defining moment for philosophical martyrdom

Plato

• Founded the Academy in Athens (c. 387 BCE)—one of the earliest institutions of higher learning, operating for nearly 300 years
• Theory of Forms posits that non-material abstract forms (like Justice, Beauty, the Good) represent true reality, while physical objects are imperfect copies
• The Republic explores the ideal state, the tripartite soul, and the concept of the philosopher-king—essential reading for political philosophy

Aristotle

• Polymath who founded the Lyceum—contributed to logic, metaphysics, ethics, biology, physics, and political theory
• Virtue ethics emphasizes character development and achieving eudaimonia (human flourishing) through the "golden mean" between extremes
• Empirical methodology prioritized observation and classification, laying groundwork for the scientific method and breaking from Plato's abstract idealism

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The Pre-Socratics: Questioning the Nature of Reality

Before Socrates turned philosophy toward ethics, earlier thinkers asked fundamental questions about what exists and what is real. These Pre-Socratic philosophers established the metaphysical debates that Plato and Aristotle would later address.

Heraclitus

• Doctrine of flux—"You cannot step into the same river twice" captures his belief that change is the fundamental nature of reality
• Logos refers to the rational principle governing the cosmos, a unifying order beneath apparent chaos
• Unity of opposites—hot and cold, life and death exist in dynamic tension, influencing later dialectical thinking and existentialism

Parmenides

• Reality is unchanging—argued that change and motion are illusions; "what is, is" and cannot come from nothing
• Poem "On Nature" distinguishes between the Way of Truth (being is eternal and unchanging) and the Way of Opinion (deceptive appearances)
• Appearance vs. reality distinction directly influenced Plato's Theory of Forms and remains central to metaphysics

Pythagoras

• Mathematical-mystical philosophy—believed numbers and their relationships reveal the structure of the universe
• Founded a religious community that practiced asceticism and believed in metempsychosis (transmigration of souls through reincarnation)
• Harmony and proportion governed both music and cosmos—the "music of the spheres" concept influenced Plato's cosmology

Democritus

• Atomic theory—proposed that all matter consists of indivisible particles called atoms moving through void (empty space)
• Materialist worldview explained natural phenomena without divine intervention, anticipating modern scientific naturalism
• Ethics of cheerfulness—achieving euthymia (tranquility) through moderation and intellectual pursuit, not religious devotion

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Hellenistic Schools: Philosophy as a Way of Life

After Aristotle, philosophy became increasingly focused on practical ethics—how to live well in an uncertain world. These schools offered competing answers to the question: What is the path to happiness?

Epicurus

• Epicureanism teaches that pleasure (hedone) is the highest good—but true pleasure means absence of pain (ataraxia), not indulgence
• The gods exist but don't intervene—eliminating fear of divine punishment and death frees humans to pursue tranquil happiness
• Garden community emphasized friendship as essential to the good life; simple pleasures and philosophical conversation over wealth and power

Zeno of Citium

• Founded Stoicism (named for the Stoa Poikile, the painted porch where he taught)—virtue alone is sufficient for happiness
• Living according to nature and reason—accept what you cannot control; focus only on your own judgments and actions
• Virtue as the highest good—external circumstances (wealth, health, reputation) are "indifferent"; only character matters

Diogenes

• Cynicism's most famous practitioner—rejected social conventions, wealth, and comfort as obstacles to virtue
• Lived in a barrel (or large ceramic jar) and performed provocative public acts to expose hypocrisy and challenge norms
• Self-sufficiency and nature—true freedom comes from needing nothing; influenced Stoic emphasis on independence from externals

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Quick Reference Table

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Self-Check Questions

1. Compare and contrast Heraclitus and Parmenides on the nature of reality. How did Plato's Theory of Forms attempt to resolve their disagreement?

2. Which two Hellenistic schools both aimed at achieving tranquility but differed on whether pleasure or virtue was the path to get there? Explain their key differences.

3. Identify the philosopher: He never wrote anything himself, was executed for "corrupting the youth," and developed a questioning method still used today. What was his core ethical teaching?

4. How does Aristotle's empirical approach represent a departure from Plato's rationalism? Give a specific example of how their methods differed.

5. If an FRQ asked you to discuss ancient philosophical responses to materialism, which three philosophers would provide the strongest examples—and would they support or challenge a materialist worldview?