Philosophy Glossary

40 key terms, each explained in plain words and checked against the Stanford Encyclopedia of Philosophy, the Internet Encyclopedia of Philosophy or Britannica, with the questions, thinkers and traditions it belongs to. More are added in checked batches.

A

A posteriori

Knowledge or justification that depends on experience, such as observation, experiment or introspection.

A priori

Knowledge or justification that does not depend on experience, such as knowing that all bachelors are unmarried.

Abduction (inference to the best explanation)

Inferring that a hypothesis is probably true because it would best explain the evidence in front of you.

Akrasia

Acting freely and deliberately against your own judgement about what is best: weakness of will.

Analytic–synthetic distinction

The contrast between statements true by meaning alone and statements whose truth also depends on how the world is.

Anattā (no-self)

The Buddhist teaching that there is no permanent, independent self underlying a person.

Ātman

In Hindu philosophy, the self: the inner core of a person, which some schools identify with ultimate reality, brahman.

B

Begging the question

Arguing for a conclusion with premises that already assume that conclusion is true.

C

Categorical imperative

Kant's supreme moral principle: a command that binds every rational agent unconditionally, whatever their desires.

Compatibilism

The view that free will and moral responsibility can exist even if determinism is true.

D

Dao

Chinese for 'way' or 'path': the guiding way of right conduct or, in Daoism, the way of the whole cosmos.

Determinism

The view that every event is fixed by earlier events together with the laws of nature.

Dualism

The view that mind and body, or the mental and the physical, are fundamentally different kinds of thing.

E

Epoché

Suspension of judgement: in ancient scepticism, withholding belief; in Husserl's phenomenology, bracketing the world's existence.

Eudaimonia

The ancient Greek idea of a flourishing human life, which Aristotle treated as the highest good.

F

Fallacy

An error in reasoning, especially an argument that seems better than it really is.

I

Induction

Reasoning from observed cases to unobserved ones or to general laws, giving conclusions that are probable rather than guaranteed.

Intentionality

The capacity of minds and mental states to be about, represent or be directed at something.

K

Kalām

Islamic speculative theology: the use of reasoned argument to defend and explain religious belief.

Karma

In Indian traditions, the principle that a person's intentional actions shape their future, including future lives.

L

Li (ritual propriety)

The Confucian practice of ritual and proper conduct, from sacrifices and funerals to everyday courtesy.

M

Moral realism

The view that moral claims state facts, and that some of them are actually true.

N

Necessary and sufficient conditions

A necessary condition must hold for something to be true; a sufficient condition guarantees that it is.

Nominalism

The view that there are no universals, or no abstract objects; only particular things exist.

P

Physicalism

The view that everything is physical, or depends in the right way on what is physical.

Pramāṇa

In Indian philosophy, a reliable source of knowledge, such as perception, inference or testimony.

Q

Qualia

The felt, subjective qualities of experience, such as the redness of seeing red or the hurt of pain.

R

Reductio ad absurdum

Establishing a claim by showing that denying it leads to a contradiction or an absurd result.

Ren

The central Confucian virtue, usually translated benevolence or humaneness: caring for others and treating them well.

S

Social contract

The idea that political authority or moral obligations rest on an agreement, real or hypothetical, among the people bound by them.

Soundness

A sound argument is a deductive argument that is valid and whose premises are all actually true.

Śūnyatā (emptiness)

The Buddhist teaching that nothing has an independent, intrinsic nature; all things exist only in dependence on others.

Supervenience

A relation between two sets of properties: one cannot differ without the other differing too.

U

Ubuntu

An African philosophical ideal of shared humanity, expressed in the saying that a person is a person through other persons.

Universals

Repeatable features, such as redness, that many separate things can share at once.

Utilitarianism

The ethical view that the right action is the one that produces the greatest overall good, counting everyone equally.

V

Validity

A deductive argument is valid when its form makes it impossible for the premises to be true and the conclusion false.

Veil of ignorance

Rawls's thought experiment: choose principles of justice without knowing what position you will hold in society.

Virtue (aretē)

An excellent and stable trait of character, such as courage or honesty, that disposes a person to act well.

W

Wu wei

The Daoist ideal of 'non-action': acting without forcing, in harmony with the natural way rather than from selfish desire.