Major Schools of Philosophy

Why This Matters

Philosophy isn't just abstract theorizing—it's the foundation of how humans have answered the biggest questions: What can we know? What is real? How should we live? In Introduction to Humanities, you're being tested on your ability to trace how these ideas evolved, how they influenced art, literature, politics, and science, and how different schools respond to and critique one another. Understanding philosophy means understanding the intellectual DNA of Western civilization.

The schools below aren't isolated islands of thought. They form a conversation across centuries, with each movement emerging partly as a response to what came before. Empiricists challenged Rationalists. Existentialists rejected systematic philosophy. Postmodernists questioned everyone. Don't just memorize names and dates—know what epistemological question (how do we know?) or metaphysical claim (what is real?) each school is answering, and how they'd argue with each other.

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The Foundations: Ancient Origins

Western philosophy begins with the Greeks, who established the very methods and questions that every later school would either build upon or rebel against. Their emphasis on reason, systematic inquiry, and the search for universal truths set the template.

Ancient Greek Philosophy

• Socrates, Plato, and Aristotle established the foundational methods of Western thought—dialectic questioning, systematic reasoning, and empirical observation
• Plato's Theory of Forms proposed that abstract, perfect ideals exist beyond the physical world, influencing later Idealism and Rationalism
• Aristotle's emphasis on observation and classification of the natural world laid groundwork for Empiricism and the scientific method

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The Knowledge Debate: How Do We Know What We Know?

One of philosophy's central battles concerns epistemology—the study of knowledge itself. These schools offer competing answers to a fundamental question: Does knowledge come from the mind or from the senses?

Rationalism

• Reason and intellect are the primary sources of knowledge—sensory experience is unreliable and potentially deceptive
• Descartes, Spinoza, and Leibniz championed innate ideas—truths the mind possesses independently of experience (think: "I think, therefore I am")
• Deductive reasoning moves from general principles to specific conclusions, contrasting with empirical methods that build from observations

Empiricism

• All knowledge derives from sensory experience—the mind begins as a tabula rasa (blank slate) that experience writes upon
• Locke, Berkeley, and Hume rejected innate ideas, arguing that even complex concepts trace back to simple sensory impressions
• Hume's skepticism pushed empiricism to its limits, questioning whether we can truly know causation or even the existence of the self

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The Reality Debate: What Actually Exists?

Metaphysics asks what the fundamental nature of reality is. These schools offer radically different answers: Is reality ultimately mental or physical?

Idealism

• Reality is fundamentally mental or spiritual—the physical world depends on perception and consciousness for its existence
• Berkeley's famous claim "esse est percipi" (to be is to be perceived) argues that objects only exist insofar as they are experienced
• Hegel expanded Idealism into a comprehensive system where history itself is the unfolding of Absolute Spirit through dialectical progression

Materialism

• Only physical matter exists—consciousness, thought, and culture are ultimately reducible to material processes
• Democritus proposed ancient atomism; Marx applied materialism to history, arguing that economic conditions shape ideas and social structures
• Challenges Idealism directly by asserting that the physical world exists independently of any mind perceiving it

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The Modern Turn: Experience, Meaning, and Action

By the 19th and 20th centuries, philosophers increasingly turned away from grand metaphysical systems toward lived experience, practical consequences, and individual existence. These schools prioritize how philosophy connects to actual human life.

Existentialism

• Individual existence precedes essence—you aren't born with a fixed nature; you create meaning through choices and actions
• Sartre, Kierkegaard, and Nietzsche explored themes of absurdity, authenticity, and radical freedom—and the anxiety that comes with it
• Rejects systematic philosophy in favor of confronting life's fundamental questions: death, meaning, responsibility, and the absence of inherent purpose

Pragmatism

• Truth is what works—ideas are validated by their practical consequences and usefulness, not correspondence to abstract reality
• Peirce, James, and Dewey developed this distinctly American philosophy, emphasizing experimentation, action, and social problem-solving
• Challenges both Rationalism and Empiricism by shifting the question from "Is this true?" to "What difference does believing this make?"

Phenomenology

• Studies consciousness itself—how things appear to us, bracketing assumptions about whether they exist objectively
• Husserl's method of "bracketing" (epoché) suspends judgments about external reality to examine pure experience
• Heidegger extended phenomenology to ask about Being itself, influencing Existentialism and hermeneutics

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The Contemporary Landscape: Language, Logic, and Critique

20th-century philosophy split into two broad traditions: one focused on rigorous logical analysis, the other on cultural critique and deconstruction. Both question whether traditional philosophy asked the right questions.

Analytic Philosophy

• Clarity and logical precision are paramount—philosophical problems often dissolve when we analyze language carefully
• Russell, Wittgenstein, and Quine emphasized that many metaphysical puzzles arise from linguistic confusion rather than genuine mysteries
• Dominates English-speaking philosophy and connects closely to formal logic, philosophy of science, and cognitive science

Postmodernism

• Rejects grand narratives and objective truth—all knowledge is shaped by power, culture, and historical context
• Foucault, Derrida, and Lyotard critique Enlightenment assumptions, exposing how "universal truths" often mask particular interests
• Deconstruction reveals hidden contradictions and assumptions in texts, challenging the stability of meaning itself

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Quick Reference Table

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Self-Check Questions

1. Both Rationalism and Empiricism address epistemology—what is the fundamental disagreement between them about the source of knowledge?

2. If an essay asks you to compare two schools with opposite metaphysical views, which pairing would best illustrate the mind-matter debate, and why?

3. How do Existentialism and Pragmatism both reject abstract philosophical systems, yet differ in what they prioritize instead?

4. A passage describes a philosopher who argues that "truth" is always shaped by power structures and cultural context. Which school does this represent, and how does it contrast with Analytic Philosophy's approach?

5. Compare and contrast: How would a Phenomenologist and an Empiricist each approach studying human perception? What would each prioritize, and what would each bracket or ignore?