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Branches of Philosophy: The Six Roots and All 131 Questions
Most lists give five to eight branches. Here are the six roots of philosophy, their core questions, and all 131 branches and sub-branches.
On this page
- How many branches of philosophy are there?
- Metaphysics: what exists, and what is it like?
- Epistemology: what can be known, and how?
- Ethics and axiology: what is good, and what should I do?
- Logic: what follows validly from what?
- Aesthetics: what is beauty, and why does art move us?
- The philosophy of X: the same questions, aimed at one part of life
- Where political philosophy, philosophy of mind and other branches fit
- All 131 branches and sub-branches of philosophy
The branches of philosophy are usually listed as five: metaphysics (what is real), epistemology (what we can know), ethics (how we should live), logic (what makes reasoning good) and aesthetics (beauty and art). A sixth family, the “philosophy of X”, turns those questions on particular fields such as science, religion, law, politics, language and mathematics.
Most lists stop there, or add two or three popular fields and call it eight. This page goes further. The Coordinates, the map at the heart of this site, divides philosophy into six roots and 131 branches and sub-branches, each stated as a question, with its rival answers and the thinkers who gave them across every tradition. Below, each root is explained in turn, followed by where the familiar named fields sit and the complete list.
How many branches of philosophy are there?
There is no official number. Divisions of philosophy are tools for finding your way, and different eras drew them differently. The Stoics split philosophy into three parts: logic, physics and ethics. Modern textbooks commonly give five main branches, which is why “5 branches of philosophy” is such a common search, and many add political philosophy, philosophy of mind or philosophy of religion to reach seven or eight.
Other traditions cut the field in other places. The Nyaya school of India built its system around the pramāṇas, the reliable means of knowledge, so that epistemology and the theory of inference grew up together. Classical Chinese thought gave ethics and government a central place. Any list of the branches of philosophy is a choice about emphasis.
The Coordinates uses six roots. Five are the classical branches; the sixth gathers the “philosophy of” fields. Together they hold 131 questions.
- IMetaphysicsWhat exists, and what is it like?24 questions
- IIEpistemologyWhat can be known, and how?18 questions
- IIIEthics and AxiologyWhat is good, and what should I do?21 questions
- IVLogicWhat follows validly from what?16 questions
- VAestheticsWhat is beauty, and why does art move us?11 questions
- VIThe Philosophy of XThe questions above, aimed at one part of life.41 questions
The main branches of philosophy at a glance
| Branch | Core question | Example sub-branches |
|---|---|---|
| Metaphysics | What exists, and what is it like? | Ontology, philosophy of mind, philosophy of time, free will and determinism |
| Epistemology | What can be known, and how? | Theories of knowledge, sources of knowledge, skepticism, truth |
| Ethics and Axiology | What is good, and what should I do? | Meta-ethics, normative ethics, applied ethics, value theory |
| Logic | What follows validly from what? | Formal logic, informal logic, modal logic, non-classical logics |
| Aesthetics | What is beauty, and why does art move us? | Theories of beauty, philosophy of art, taste and judgement, the sublime |
| The Philosophy of X | The questions above, aimed at one part of life | Philosophy of science, political philosophy, philosophy of religion, philosophy of language |
Metaphysics: what exists, and what is it like?
Metaphysics studies the most general features of reality: what kinds of thing exist, what time and space are, what a cause is, whether the mind is something physical, and whether our choices are free. Its questions are not settled by looking harder, because they concern how anything we observe should be understood. It is the largest of the five classical roots, with 24 cards, including:
- Ontology: What is there? Materialism, idealism, dualism, neutral monism and pluralism give rival answers.
- Philosophy of Mind: What is a mind, and how does it relate to the body and the world?
- Philosophy of Time: Does time pass, or does it only seem to?
- Free Will and Determinism △: Could you have done otherwise?
- Cosmology (Philosophical): Why is there something rather than nothing?
Its key figures run from Parmenides and Aristotle to Nagarjuna, Śaṅkara, Ibn Sina, Quine and Heidegger. Read the full guide: what is metaphysics?
Epistemology: what can be known, and how?
Epistemology is the theory of knowledge. It asks what separates knowing from merely believing, where knowledge comes from, how a belief is held up by reasons, and whether the sceptic who doubts everything can be answered. Its 18 cards include:
- Theories of Knowledge: What has to be added to a true belief to make it knowledge?
- Sources of Knowledge: Which ways of finding things out actually work? Here the Indian schools are central: the Carvaka accepted perception alone, Buddhist logicians following Dignāga accepted perception and inference, and the Nyaya school four sources, including testimony.
- Skepticism: How do you know you are not being deceived about everything?
- Truth: What makes a statement true?
- Social Epistemology: Much of what you know depends on other people. What follows?
Read the full guide: what is epistemology?
Ethics and axiology: what is good, and what should I do?
Ethics asks how we ought to act and live; axiology, from the Greek axios, “worthy”, is the wider theory of value. The root works at three levels: meta-ethics asks what a moral claim is, normative ethics asks what makes acts right or wrong, and applied ethics works on real cases. It has 21 cards, including:
- Meta-Ethics: When you say cruelty is wrong, what kind of statement are you making?
- Normative Ethics: What should I look at to tell whether an act is right? Rival answers include consequences, duty, character, contract, care, divine command, Confucian role ethics and Ubuntu.
- Applied Ethics: What should be done in this case? Its sub-branches include Bioethics and Medical Ethics △, Environmental Ethics and Animal Ethics.
- Value Theory: What would make your life go well, apart from being moral?
Read the full guide: what is ethics?
Logic: what follows validly from what?
Logic is the study of good reasoning. Formal logic asks which inferences are valid by their structure alone; informal logic studies arguments as people actually make them, with unstated premises and conclusions that are supported rather than guaranteed. Logic was developed independently in Greece, by Aristotle and the Stoics, and in India, by the Nyaya school and Buddhist logicians such as Dignāga. Its 16 cards include:
- Formal Logic: What makes an argument work, regardless of its subject?
- Predicate Logic: Why could two thousand years of logic not handle “every boy loves some girl”?
- Fallacies: When is a bad-looking argument actually bad?
- Modal Logic: How do you reason validly about what must be, and what merely might?
- Philosophy of Logic: Is logic discovered or invented?
Read the full guide: what is logic?
Aesthetics: what is beauty, and why does art move us?
Aesthetics studies beauty, art and taste, and the experiences they produce in us. It asks whether beauty is in the object or in the response, what makes something art, and whether one person’s taste can be better than another’s. Its 11 cards include:
- Theories of Beauty: Is beauty in the object or in the eye?
- Philosophy of Art: What is art, what does it do, and why does it matter? Answers range from imitation and expression to institutional theories and the Indian theory of rasa, first set out in Bharata’s Nāṭyaśāstra and developed by Abhinavagupta.
- Taste and Judgement: Is someone who prefers worse art making a mistake?
- The Sublime: Why do we seek out what frightens us?
- Everyday and Natural Aesthetics: Is a mountain beautiful in the same way a painting is?
Read the full guide: what is aesthetics?
The philosophy of X: the same questions, aimed at one part of life
The sixth root is the largest, with 41 cards. Each “philosophy of” field takes the questions of the other five, about what exists, what can be known, what is good and what follows, and aims them at one domain: a science, an institution, or an ordinary part of human life. It includes:
- Philosophy of Science: What makes a claim scientific?
- Political Philosophy △: When is political power legitimate, and what may it rightly do?
- Philosophy of Religion: What kind of claim is a religious claim?
- Philosophy of Language: How do noises come to be about things?
- Meaning in Life: Does a life need a point, and where would it come from?
It also reaches newer and less obvious fields: artificial intelligence, disability, food and humour. Read the full guide: the philosophy of X.
Where political philosophy, philosophy of mind and other branches fit
Lists of the types of philosophy often name fields that do not appear among the classical five. Here is where the most searched-for ones sit.
- Political philosophy is card 6.4 in the philosophy of X family, with its own sub-branches on distributive justice, rights and liberty and sovereignty and the state. Many lists treat it as a main branch in its own right; it draws heavily on ethics. Conversations: Society & Politics.
- Philosophy of mind sits under metaphysics (1.3), because its central question, what a mind is, is a question about what exists. Its close neighbours, philosophy of psychology and philosophy of artificial intelligence, sit in the sixth root. Conversations: Mind & Self.
- Philosophy of science is 6.8, with sub-branches on explanation, scientific realism and scientific revolutions. It borders epistemology closely. Conversations: Science & Technology.
- Philosophy of religion is 6.1, but its questions are spread across the map: natural theology (1.8) sits in metaphysics and revelation (2.2.5) in epistemology. Conversations: Religion & the Sacred.
- Philosophy of language is 6.10, a near neighbour of logic. Conversations: Logic, Language & Mathematics.
Some things called “types of philosophy” are not branches at all. Stoicism, existentialism and pragmatism are schools; Indian, Chinese, Islamic and African philosophy are traditions. A branch is a set of questions. Schools and traditions are families of answers, and each of them takes positions across many branches at once.
All 131 branches and sub-branches of philosophy
Here is the complete list, grouped by root, each with its question. The cards come from The Coordinates of Thought by Syed Raheel Shahzad, which sets out every side and takes none. Questions marked △ are contested: philosophers disagree about the question itself, not only about the answer. Open any card to see its rival answers, the thinkers behind them, and the conversation on this site.
Root I — Metaphysics 24 cards
- 1.1 OntologyWhat is there?
- 1.1.1 Substance TheoryIs a river a thing, or an event?
- 1.1.2 Universals and ParticularsA tomato and a fire engine are both red. Is there something they share?
- 1.1.3 MereologyWhen do some things make one thing?
- 1.1.4 Abstract ObjectsDoes the number seven exist?
- 1.2 Cosmology (Philosophical)Why is there something rather than nothing?
- 1.2.1 Origins and First CauseDid anything ever start, or has it always been running?
- 1.2.2 Fine-Tuning and NecessityCould the universe have had different laws?
- 1.3 Philosophy of MindWhat is a mind, and how does it relate to the body and the world?
- 1.3.1 The Mind–Body ProblemHow can a thought move an arm?
- 1.3.2 Personal IdentityAre you the same person you were at five?
- 1.3.3 IntentionalityHow can one thing be about another thing?
- 1.3.4 Qualia and the Hard Problem △ contestedWhy isn't it all dark inside?
- 1.4 Philosophy of TimeDoes time pass, or does it only seem to?
- 1.4.1 Persistence and ChangeIf you are bent when sitting and straight when standing, how can both be true of you?
- 1.4.2 CausationWhat do you actually see when you see one thing cause another?
- 1.5 Philosophy of SpaceIf every object vanished, would space still be there?
- 1.6 ModalityWhat does it mean to say something could have been different?
- 1.6.1 Possible WorldsWhen you say something could have gone differently, what are you talking about?
- 1.7 Free Will and Determinism △ contestedCould you have done otherwise?
- 1.8 Natural Theology △ contestedCan argument alone settle whether God exists?
- 1.9 Laws of NatureDo laws of nature make things happen, or only describe what happens?
- 1.10 Meta-Metaphysics △ contestedAre metaphysical arguments about anything?
- 1.11 Emergence and ReductionIs chemistry just physics, and biology just chemistry?
Root II — Epistemology 18 cards
- 2.1 Theories of KnowledgeWhat has to be added to a true belief to make it knowledge?
- 2.1.1 The Gettier ProblemCan you be right for the wrong reasons and still count as knowing?
- 2.2 Sources of KnowledgeWhich ways of finding things out actually work?
- 2.2.1 PerceptionWhen you see a tree, what are you actually seeing?
- 2.2.2 Reason and IntuitionHow, if at all, do you know that a surface cannot be wholly red and wholly green at the same time and in the same respect?
- 2.2.3 MemoryIs remembering a kind of perceiving, or a kind of imagining?
- 2.2.4 TestimonyDo you need a reason to trust, or a reason not to?
- 2.2.5 Revelation △ contestedCan something be known because it was disclosed rather than discovered?
- 2.3 Structure of JustificationWhy do you believe that? And why do you believe that?
- 2.3.1 Foundationalism vs CoherentismIs knowledge a building or a raft?
- 2.3.2 Internalism vs ExternalismDo you have to know why you know?
- 2.4 SkepticismHow do you know you are not being deceived about everything?
- 2.4.1 Global vs Local SkepticismCan you doubt everything, or only something?
- 2.5 TruthWhat makes a statement true?
- 2.6 RationalityIs it rational to believe what the evidence supports, or what serves you?
- 2.7 Social EpistemologyMuch of what you know depends on other people. What follows?
- 2.7.1 Disagreement and ExpertiseShould the fact that someone disagrees with you change your mind?
- 2.8 Formal EpistemologyBy how much should this evidence move you?
Root III — Ethics and Axiology 21 cards
- 3.1 Meta-EthicsWhen you say cruelty is wrong, what kind of statement are you making?
- 3.1.1 Moral Realism vs Anti-RealismIf everyone approved of torturing children, would it still be wrong?
- 3.1.2 Moral SemanticsDoes "wrong" describe an act, or do something to the listener?
- 3.1.3 Moral EpistemologyHow would you check whether a moral claim is true?
- 3.1.4 Moral MotivationCan you know an act is wrong and be entirely unmoved?
- 3.2 Normative EthicsWhat should I look at to tell whether an act is right?
- 3.2.1 Consequence-Based ApproachesIf an act produces the best outcome, can it be wrong?
- 3.2.2 Duty-Based ApproachesAre some things wrong even when they would do good?
- 3.2.3 Character-Based ApproachesShould ethics ask what to do, or who to be?
- 3.2.4 Contract-Based ApproachesCould you justify this to everyone it affects?
- 3.2.5 Care and Relational ApproachesDoes morality start with rules, or with the people you are responsible for?
- 3.2.6 Divine Command ApproachesHow does a command create an obligation?
- 3.3 Applied EthicsWhat should be done in this case?
- 3.3.1 Bioethics and Medical Ethics △ contestedWho counts, who decides, and who gets it?
- 3.3.2 Environmental EthicsDoes a forest matter only because people value it?
- 3.3.3 Business and Economic EthicsDoes a company owe anything to anyone but its owners?
- 3.3.4 Ethics of Technology and AIWho is responsible when a machine causes harm and no one intended it?
- 3.3.5 War and Political Violence △ contestedCan killing be permitted when it would otherwise be murder?
- 3.3.6 Animal EthicsWhat is it about humans that makes us count?
- 3.4 Moral PsychologyAre people naturally good, naturally selfish, or naturally neither?
- 3.5 Value TheoryWhat would make your life go well, apart from being moral?
Root IV — Logic 16 cards
- 4.1 Formal LogicWhat makes an argument work, regardless of its subject?
- 4.1.1 Propositional LogicWhat follows from "if this, then that"?
- 4.1.2 Predicate LogicWhy could two thousand years of logic not handle "every boy loves some girl"?
- 4.1.3 Syllogistic LogicWhat follows from two statements about classes of things?
- 4.2 Informal LogicWhy does formal logic tell you so little about whether an argument is any good?
- 4.2.1 FallaciesWhen is a bad-looking argument actually bad?
- 4.2.2 Argumentation TheoryWhat does an argument have to do, besides be valid?
- 4.2.3 RhetoricIs persuading someone different from giving them a reason?
- 4.3 Modal LogicHow do you reason validly about what must be, and what merely might?
- 4.3.1 Deontic LogicWhat follows logically from "you must"?
- 4.3.2 Epistemic LogicIf you know something, do you know that you know it?
- 4.3.3 Temporal LogicIs it already true that it will rain tomorrow?
- 4.4 Non-Classical Logics △ contestedWhich parts of classical logic, if any, should be revised — and for which problems?
- 4.4.1 Many-Valued and Fuzzy LogicCan a statement be partly true?
- 4.4.2 Paraconsistent LogicIf you believe one contradiction, must you believe everything?
- 4.5 Philosophy of LogicIs logic discovered or invented?
Root V — Aesthetics 11 cards
- 5.1 Theories of BeautyIs beauty in the object or in the eye?
- 5.2 Philosophy of ArtWhat is art, what does it do, and why does it matter?
- 5.2.1 Definition and BoundariesCan anything be art if someone says it is?
- 5.2.2 Artistic IntentionDoes the artist get to say what the work means?
- 5.2.3 InterpretationCan you misread a poem?
- 5.3 Taste and JudgementIs someone who prefers worse art making a mistake?
- 5.4 The SublimeWhy do we seek out what frightens us?
- 5.5 Aesthetic ExperienceWhy is the sadness of a sad song enjoyable?
- 5.6 Art and MoralityCan a beautiful work be evil, and still beautiful?
- 5.7 Everyday and Natural AestheticsIs a mountain beautiful in the same way a painting is?
- 5.8 Philosophy of Music and LiteratureHow can a piece of music be sad?
Root VI — The Philosophy of X Family 41 cards
- 6.1 Philosophy of ReligionWhat kind of claim is a religious claim?
- 6.1.1 Religious ExperienceIf someone tells you they have met God, what have you learned?
- 6.2 Philosophy of LawIs an unjust law still a law?
- 6.3 Philosophy of EducationIs education filling someone up, or drawing something out?
- 6.4 Political Philosophy △ contestedWhen is political power legitimate, and what may it rightly do?
- 6.4.1 Distributive Justice △ contestedWho should get what — and why?
- 6.4.2 Rights and LibertyAre you free when nobody stops you, or when you could actually do it?
- 6.4.3 Sovereignty and the StateWho holds final authority, and what makes it final?
- 6.5 Philosophy of EconomicsAre economic models describing people, or a convenient fiction about them?
- 6.6 Philosophy of HistoryIs history going anywhere?
- 6.7 Social OntologyWhat makes social facts and entities real, and how do they depend on individuals?
- 6.8 Philosophy of ScienceWhat makes a claim scientific?
- 6.8.1 Scientific ExplanationWhen have you explained something, rather than just described it?
- 6.8.2 Scientific RealismDo electrons exist, or do they just work?
- 6.8.3 Scientific RevolutionsDoes science build on what came before, or replace it?
- 6.9 Philosophy of MathematicsAre numbers discovered or invented?
- 6.10 Philosophy of LanguageHow do noises come to be about things?
- 6.10.1 ReferenceWhat makes your word for a thing refer to that thing?
- 6.10.2 Speech ActsHow does saying "I promise" make a promise?
- 6.11 Philosophy of PhysicsWhat is quantum theory telling us about the world?
- 6.12 Philosophy of BiologyIs there purpose in living things?
- 6.13 Philosophy of MedicineWhat makes something a disease rather than a difference?
- 6.14 Philosophy of PsychologyCan a science study something only one person can observe?
- 6.15 Philosophy of Social ScienceCan there be laws of human behaviour?
- 6.16 Philosophy of TechnologyDo we shape our tools, or do they shape us?
- 6.17 Philosophy of Artificial Intelligence △ contestedWhat would a machine have to do to count as thinking?
- 6.18 Philosophy of InformationIs information something in the world, or something we bring to it?
- 6.19 Philosophy of Love and FriendshipDo you love someone for their qualities, or for being them?
- 6.20 Philosophy of DeathCan something be bad for you if you are not there for it?
- 6.21 Meaning in LifeDoes a life need a point, and where would it come from?
- 6.22 Philosophy of WorkIs work a cost to be minimised or a good in itself?
- 6.23 Philosophy of EmotionCan an emotion be wrong?
- 6.24 Philosophy of ActionWhat is the difference between your arm rising and your raising it?
- 6.25 Philosophy of Sport and PlayWhy does it matter whether the ball crossed a line we drew?
- 6.26 Philosophy of FoodCan you be wrong about what tastes good?
- 6.27 Philosophy of HumourWhy is anything funny?
- 6.28 Philosophy of DisabilityIs the difficulty in the body or in the world it meets?
- 6.29 Philosophy of Gender △ contestedWhat kind of thing is a gender category?
- 6.30 Philosophy of Race △ contestedIf race is not biological, what is it?
- 6.31 Philosophy of CultureCan you understand a culture from outside it?
- 6.32 Philosophy of Film and MediaHow do images argue?
Where do you stand?
Every question here has serious answers on more than one side. Pick a card, read the rival answers, then say which you find strongest and why. Members ask, reply and take sides; reading is free for everyone.