1. RENÉ DESCARTES — Radical Doubt and Foundational Certainty
| Dimension | Position |
|---|
| Core idea | Knowledge must begin from indubitable certainty |
| Orientation | Rationalist foundationalism |
| Method | Methodic doubt |
| Ontology | Dualism (mind vs matter) |
| Key principle | “Cogito ergo sum” (I think, therefore I am) |
| Reality structure | Res cogitans (mind) + res extensa (matter) |
| Epistemology | Innate ideas + deductive reasoning |
| Philosophical goal | Secure absolute foundation for knowledge |
2. GEORGE BERKELEY — Idealism and the Immaterial World
| Dimension | Position |
|---|
| Core idea | To be is to be perceived (esse est percipi) |
| Orientation | Empirical idealism |
| Method | Radical empiricism |
| Ontology | Only minds and ideas exist |
| Matter | Denied as independent substance |
| Key principle | Reality depends on perception |
| God’s role | Infinite perceiver sustaining existence |
| Philosophical aim | Eliminate material substance to avoid skepticism |
3. DAVID HUME — Radical Empiricism and Skeptical Naturalism
| Dimension | Position |
|---|
| Core idea | All knowledge derives from experience |
| Orientation | Empiricist skepticism |
| Method | Psychological analysis of perception |
| Ontology | Bundle theory of self (no fixed identity) |
| Causality | Habit, not necessity |
| Self | No stable “I,” only impressions and ideas |
| Key principle | Knowledge limited to impressions |
| Philosophical outcome | Deep skepticism about metaphysics |
4. IMMANUEL KANT — Critical Philosophy and Conditions of Knowledge
| Dimension | Position |
|---|
| Core idea | Knowledge is shaped by mind’s structures |
| Orientation | Transcendental idealism |
| Method | Critique of pure reason |
| Ontology | Phenomena vs noumena distinction |
| Key principle | Mind structures experience (categories of understanding) |
| Space & time | A priori forms of intuition |
| Causality | Necessary category of cognition |
| Philosophical goal | Solve rationalism vs empiricism conflict |
5. GEORG WILHELM FRIEDRICH HEGEL — Dialectical Absolute Idealism
| Dimension | Position |
|---|
| Core idea | Reality is unfolding rational process |
| Orientation | Absolute idealism |
| Method | Dialectical logic (thesis–antithesis–synthesis) |
| Ontology | Reality = Spirit (Geist) developing itself |
| History | Rational unfolding of Spirit |
| Self | Achieves self-consciousness through others |
| Knowledge | Absolute knowing through dialectic |
| Philosophical goal | Complete unity of thought and being |
6. STRUCTURAL EVOLUTION OF MODERN PHILOSOPHY
| Stage | Thinker | Core Shift |
|---|
| Certainty foundation | Descartes | Knowledge grounded in self-conscious subject |
| Perception idealism | Berkeley | Reality depends on perception |
| Skeptical breakdown | Hume | Knowledge reduced to habit and impressions |
| Critical reconstruction | Kant | Mind structures experience |
| Dialectical totality | Hegel | Reality as self-developing reason |
7. EPISTEMOLOGICAL SHIFT: WHAT IS KNOWLEDGE?
| Thinker | Source of Knowledge | Certainty Level |
|---|
| Descartes | Reason + innate ideas | Absolute certainty (cogito) |
| Berkeley | Perception | Certainty via divine guarantee |
| Hume | Sensory impressions | Probabilistic skepticism |
| Kant | Structured cognition | Conditional certainty (phenomena only) |
| Hegel | Dialectical reason | Absolute but historical unfolding |
8. CONCEPT OF SELF (SUBJECTIVITY)
| Thinker | Model of Self |
|---|
| Descartes | Thinking substance (res cogitans) |
| Berkeley | Spiritual perceiving mind |
| Hume | Bundle of perceptions (no essence) |
| Kant | Transcendental unity of apperception |
| Hegel | Self-conscious Spirit through recognition |
9. REALITY STRUCTURE (ONTOLOGY)
| Thinker | Structure of Reality |
|---|
| Descartes | Dualism: mind and matter |
| Berkeley | Idealism: only minds and ideas |
| Hume | Phenomenalism: only impressions |
| Kant | Dual structure: phenomena vs noumena |
| Hegel | Monism: Absolute Spirit unfolding |
10. HISTORY OF REASON (INTELLECTUAL TRAJECTORY)
| Stage | Movement of Thought |
|---|
| Descartes | Establish certainty through subject |
| Berkeley | Collapse matter into perception |
| Hume | Dissolve causality and self |
| Kant | Rebuild knowledge via cognitive structure |
| Hegel | Resolve contradictions in total system |
FINAL SYNTHESIS: STRUCTURAL ARC OF MODERN PHILOSOPHY
Across these thinkers, modern philosophy moves through a deep transformation:
Core trajectory:
Certainty → Perception → Skepticism → Critique → Absolute System
Or more structurally:
- Descartes: Foundation of subject
- Berkeley: Collapse of matter into mind
- Hume: Collapse of stable knowledge
- Kant: Reconstruction via conditions of possibility
- Hegel: Totalization into historical reason
META-INSIGHT
This sequence represents a full philosophical cycle:
- From foundational subjectivity (Descartes)
- To idealism and perception (Berkeley)
- To radical skepticism (Hume)
- To critical philosophy (Kant)
- To absolute system (Hegel)
Deep structure:
Certainty → Illusion → Collapse → Critique → Totality