- A Treatise Concerning the Principles of Human Knowledge
- Abstract and concrete
- Abstract object theory
- Action (philosophy)
- Action theory (sociology)
- Activity theory
- Alexius Meinong
- Alfred North Whitehead
- Alfred R. Mele
- Alfred Schütz
- Alvin I. Goldman
- Alvin Plantinga
- Anima mundi
- Anthony Kenny
- Aristotle
- Arnold Gehlen
- Arthur Schopenhauer
- August Cieszkowski
- Axiology
- Baruch Spinoza
- Being and Nothingness
- Being and Time
- Bernard Bolzano
- Bertrand Russell
- Brian O'Shaughnessy (philosopher)
- Candace Vogler
- Carl Ginet
- Carl Hempel
- Category of being
- Causal closure
- Causality
- Charles Sanders Peirce
- Charles Taylor (philosopher)
- Christian Wolff (philosopher)
- Christine Korsgaard
- Cogito, ergo sum
- Concept
- Concluding Unscientific Postscript to Philosophical Fragments
- Constantine Sandis
- Cosmology
- Critique of Pure Reason
- Cybernetics
- Daneshnameh-ye Alai
- Daniel Dennett
- David Charles (philosopher)
- David Hume
- David Lewis (philosopher)
- David Malet Armstrong
- David Velleman
- De rerum natura
- Derek Parfit
- Derk Pereboom (philosopher)
- Doi (identifier)
- Donald Davidson (philosopher)
- Duns Scotus
- Economics
- Edward N. Zalta
- Efficient cause
- Elijah Millgram
- Embodied cognition
- Empirical test
- Enactivism
- Enneads
- Essence
- Essentialism
- Ethics (Spinoza book)
- Existence
- Experience
- Feminist metaphysics
- Francisco Suárez
- Fred Dretske
- Friedrich Nietzsche
- G. E. M. Anscombe
- G. E. Moore
- Galen Strawson
- Georg Henrik von Wright
- Georg Wilhelm Friedrich Hegel
- George Berkeley
- Gilbert Ryle
- Gilles Deleuze
- Gottfried Wilhelm Leibniz
- Hannah Arendt
- Hans Joas
- Harry Frankfurt
- Hector-Neri Castañeda
- Henri Bergson
- Hermann Lotze
- Hilary Putnam
- Humeanism
- Hypostatic abstraction
- ISBN (identifier)
- Idea
- Identity (philosophy)
- Ignacio Ellacuría
- Immanuel Kant
- Index of metaphysics articles
- Information
- Insight
- Intelligence
- Intention
- Internet Encyclopedia of Philosophy
- Interpretations of quantum mechanics
- Isaac Newton
- Jaegwon Kim
- Jean-Paul Sartre
- Jennifer Hornsby
- John Hyman (philosopher)
- John Locke
- John Martin Fischer
- John McDowell
- John Searle
- Jonathan Bennett (philosopher)
- Jonathan Dancy
- Joseph Raz
- Juan Antonio Pérez López
- Judith Jarvis Thomson
- Jurisprudence
- Jürgen Habermas
- Liberty
- Linguistic modality
- List of academic disciplines
- List of metaphysicians
- Loet Leydesdorff
- Lucy O'Brien
- Ludwig von Mises
- Martin Heidegger
- Matter (philosophy)
- Maurice Blondel
- Max Weber
- Meaning (existential)
- Meaning of life
- Meditations on First Philosophy
- Mental representation
- Mereology
- Meta
- Metaphysical necessity
- Metaphysics (Aristotle)
- Michael A. Smith (philosopher)
- Michael Bratman
- Michael Dummett
- Michel Crozier
- Mind
- Monadology
- Motion
- Motor system
- Nature (philosophy)
- Neuroscience
- Nicolas Malebranche
- Nicomachean Ethics
- Nyāya Sūtras
- Object (philosophy)
- P. F. Strawson
- Parmenides
- Pattern
- Paul Ricoeur
- Perception
- Phenomenalism
- Philosophy of psychology
- Philosophy of self
- Philosophy of space and time
- Physical object
- Plato
- Plotinus
- Praxeology
- Principle
- Proclus
- Prolegomena to Any Future Metaphysics
- Property (philosophy)
- Psychology
- Qualia
- Quality (philosophy)
- R. G. Collingwood
- R. Jay Wallace
- Rational choice
- Rationality
- Raymond Reiter
- Relations (philosophy)
- René Descartes
- Richard Taylor (philosopher)
- Robert Audi
- Robert Kane (philosopher)
- Rosalind Hursthouse
- Rudolf Carnap
- Sam Harris
- Saul Kripke
- Scott Sehon
- Simulacra and Simulation
- Social action
- Social science
- Sociological
- Sophist (dialogue)
- Soul
- Stanford Encyclopedia of Philosophy
- Subject (philosophy)
- Substance theory
- Substantial form
- Susan Wolf
- Tadeusz Kotarbiński
- Talcott Parsons
- Teleology
- Telos
- The Phenomenology of Spirit
- The Philosophy of Freedom
- The World as Will and Representation
- Theory
- Theory of forms
- Thomas Aquinas
- Thomas Nagel
- Thomas Reid
- Thought
- Timaeus (dialogue)
- Time
- Truth
- Truthmaker theory
- Type theory
- Type–token distinction
- Universal (metaphysics)
- Unobservable
- Value (ethics)
- Wilfrid Sellars
- Will (philosophy)
- Willard Van Orman Quine
- William H. Dray
- Xavier Zubiri