A.J. Ayer

1910-1989 · British · Logical Positivism, Empiricist Philosophy of Mind, Ethics, Philosophical Method

No moral system can rest solely on authority.

A brilliant, dapper Old Etonian who would later be knighted and become a fixture of BBC philosophy broadcasts, A.J. Ayer made his name at twenty-six with a slim, audacious book that tried to demolish most of philosophy. Fresh from a 1932 visit to Vienna, where he had absorbed the doctrines of the Vienna Circle, he returned and rendered their hard-edged empiricism into elegant, combative English. The result, Language, Truth and Logic (1936), became one of the most influential philosophy books of the century.

Topics A.J. Ayer addresses

• the verification principle
• the elimination of metaphysics
• logical positivism
• emotivism
• the analytic/synthetic distinction
• pseudo-propositions
• literal meaning and cognitive content
• tautologies
• the rejection of synthetic a priori knowledge
• phenomenalism
• sense-data theory
• the construction of the physical world from sense-experience
• knowledge as having the right to be sure
• the problem of other minds
• the argument from analogy
• personal identity
• the Humean regularity theory of causation
• the rejection of necessary connection
• induction and probability
• free will and compatibilism
• the Vienna Circle
• emotivism in aesthetics
• the boo/hoorah theory
• the empiricist theory of meaning

Questions to put to A.J. Ayer

The Verification Principle and the Elimination of Metaphysics

• What exactly is the verification principle?
• How do you distinguish meaningful statements from meaningless pseudo-propositions?
• Why do you think metaphysical claims about God or the Absolute are literally meaningless rather than just false?
• How did you refine the verification principle after the criticisms in the 1946 introduction?
• What's the difference between weak and strong verifiability?
• How do you respond to the charge that the verification principle itself fails its own test?

Emotivism and the Analysis of Moral Judgments

• What do you mean when you say ethical concepts are pseudo-concepts?
• How is saying 'murder is wrong' different from just saying 'boo to murder'?
• If moral statements just express attitudes, how can we have genuine moral disagreements?
• Why can't moral statements describe real moral facts that exist independently of our feelings?
• How did you refine your emotivism in response to critics like Hare?

Phenomenalism and the Construction of the Physical World

• What are sense-data and why do they matter for understanding perception?
• How do you build up knowledge of physical objects from sense-experience?
• Why don't we directly perceive physical objects like tables and chairs?
• What's the difference between your mature phenomenalism and the strict 1940 version?
• How do you respond to Austin's attack on sense-data theory in Sense and Sensibilia?

The Analytic/Synthetic Distinction and Mathematics

• What's the difference between analytic and synthetic propositions?
• Why do you think mathematical truths are tautologies that tell us nothing about the world?
• How do you respond to Kant's claim that there are synthetic a priori truths?
• What's your answer to Quine's attack on the analytic/synthetic distinction in 'Two Dogmas'?
• If logic and mathematics are just tautologies, why are they so useful in science?

Causation, Induction, and Probability

• Why do you follow Hume in saying causation is just regular succession?
• What's wrong with thinking there's a necessary connection between cause and effect?
• How do you justify inductive reasoning through probability rather than metaphysics?
• How does your regularity theory of causation relate to your compatibilist view of free will?
• Can we really have scientific knowledge if causation is just observed regularity?

Other Minds, Personal Identity, and the Concept of a Person

• How does the argument from analogy give us knowledge of other minds?
• Why isn't it a problem that you're generalizing from just one case — your own mind?
• What makes someone the same person over time?
• How do bodily continuity and mental continuity both contribute to personal identity?
• How do you avoid both Cartesian dualism and behaviorist reduction in your account of persons?

Converse with A.J. Ayer on Simposeum. Replies are grounded in A.J. Ayer's own writing, cited to the page.