### Ancient
Socrates (469-399 BCE)
- Knowledge of ignorance, pursuit through dialogue. "Know thyself."
Plato (427-347 BCE)
- Theory of Forms, immortality of the soul, philosopher-king.
- Disciple of Socrates, developed his teacher's ideas.
Aristotle (384-322 BCE)
- Realism, metaphysics, logic, ethics, politics, natural science.
- Disciple of Plato, critiqued and developed beyond the Theory of Forms into realism.
### Medieval
Augustine (354-430)
- Fusion of Christian theology and Platonic philosophy, original sin and grace.
- Integrated Plato's ideas into Christian theology.
Thomas Aquinas (1225-1274)
- Synthesis of Aristotelian philosophy and Christian theology, Scholasticism.
- Integrated Aristotle's ideas into Christian theology.
### Modern
Descartes (1596-1650)
- Rationalism, methodological skepticism, "Cogito, ergo sum." Mind-body dualism.
- Criticized Medieval Scholasticism, proposed a new philosophical methodology.
Locke (1632-1704)
- Empiricism, social contract theory, natural rights, property rights.
- Opposed Descartes' rationalism, advocated empiricism.
Hume (1711-1776)
- Empiricism, skepticism, critique of causality, theory of moral sentiments.
- Developed Locke's empiricism, critiqued causality and religion.
Kant (1724-1804)
- Critical philosophy, transcendental idealism, moral law.
- Inspired by Hume's skepticism, restructured epistemology.
### 19th Century
Hegel (1770-1831)
- Dialectics, absolute spirit, philosophy of history.
- Expanded Kant's epistemology, emphasized historical development.
Kierkegaard (1813-1855)
- Existentialism, absurdity, leap of faith.
- Opposed Hegel's systematic philosophy, focused on individual existence.
Marx (1818-1883)
- Historical materialism, critique of capitalism, communism.
- Applied Hegel's dialectics to materialism, advocated social change.
Nietzsche (1844-1900)
- Critique of nihilism, Übermensch, will to power, eternal recurrence.
- Influenced by Hegel and Kierkegaard, critiqued traditional values.
### 20th Century
Husserl (1859-1938)
- Founder of phenomenology. Introduced concepts of intentionality and eidetic intuition.
- Developed Descartes' methodological skepticism into phenomenology.
Russell (1872-1970)
- Pioneer of analytic philosophy. Proposed logical atomism and theory of descriptions. Aimed to clarify the logical structure of language.
- Influenced by Frege, explored the philosophy of logic and mathematics.
Karl Barth (1886-1968)
- Major representative of dialectical theology. Emphasized the roles of revelation and faith. Asserted God's absolute transcendence.
- Reconstructed theology based on the tradition of the Reformation.
Heidegger (1889-1976)
- Innovator in ontology. Developed phenomenology into an analysis of Dasein and the meaning of Being.
- Disciple of Husserl, expanded phenomenology into ontology.
Wittgenstein (1889-1951)
- Philosophy of language, logical positivism, language games.
- Disciple of Russell, evolved from early logical positivism to later language game theory.
Quine (1908-2000)
- Analytic philosopher. Argued against reductionism and the indeterminacy of meaning thesis. Questioned the foundations of scientific knowledge.
- Influenced by Russell and Wittgenstein, critically examined language and science.
Sartre (1905-1980)
- Existentialism, freedom and responsibility, existence precedes essence.
- Developed existentialism from Heidegger's ontology.
Foucault (1926-1984)
- Post-structuralism, power theory, relationship between knowledge and power, disciplinary power.
- Influenced by Nietzsche, explored the interplay of power and knowledge.
### Contemporary
Rawls (1921-2002)
- Political philosophy, theory of justice, veil of ignorance, difference principle.
- Applied Kant's moral philosophy to political theory.
Jacques Derrida (1930-2004)
- Proponent of deconstruction. Explored the multiplicity of meanings and the indeterminacy of language. Critically dismantled the assumptions of Western metaphysics.
- Influenced by Heidegger and Foucault, aimed to deconstruct metaphysical assumptions.
Butler (1956-)
- Post-structuralism, feminism, gender theory, performativity.
- Influenced by Derrida and Foucault, analyzed gender and sexuality.