Ideas of A.J. Ayer, by Theme

[British, 1910 - 1989, Born London. Taught by Gilbert Ryle. Visited Vienna Circle in early 1930s. Professor at Universities of London and Oxford.]

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1. Philosophy / D. Nature of Philosophy / 3. Philosophy Defined

5196	Philosophy is a department of logic

1. Philosophy / D. Nature of Philosophy / 5. Aims of Philosophy / e. Philosophy as reason

5189	Philosophers should abandon speculation, as philosophy is wholly critical

1. Philosophy / E. Nature of Metaphysics / 7. Against Metaphysics

7919	Humeans rejected the a priori synthetic, and so rejected even Kantian metaphysics [Macdonald,C]

1. Philosophy / F. Analytic Philosophy / 7. Limitations of Analysis

5195	Critics say analysis can only show the parts, and not their distinctive configuration

1. Philosophy / G. Scientific Philosophy / 3. Scientism

5179	Philosophy deals with the questions that scientists do not wish to handle

2. Reason / E. Argument / 3. Analogy

5331	You can't infer that because you have a hidden birth-mark, everybody else does

2. Reason / F. Fallacies / 1. Fallacy

19463

Induction assumes some uniformity in nature, or that in some respects the future is like the past

3. Truth / H. Deflationary Truth / 2. Deflationary Truth

4749	We cannot analyse the concept of 'truth', because it is simply a mark that a sentence is asserted

6. Mathematics / C. Sources of Mathematics / 6. Logicism / a. Early logicism

5202	Maths and logic are true universally because they are analytic or tautological

7. Existence / D. Theories of Reality / 1. Ontologies

6523	Positivists regard ontology as either meaningless or stipulated [Robinson,H]

7. Existence / D. Theories of Reality / 11. Ontological Commitment / b. Commitment of quantifiers

2611	It is currently held that quantifying over something implies belief in its existence

9. Objects / D. Essence of Objects / 3. Individual Essences

16520

We see properties necessary for a kind (in the definition), but not for an individual

11. Knowledge Aims / B. Certain Knowledge / 1. Certainty

5183	Only tautologies can be certain; other propositions can only be probable

11. Knowledge Aims / B. Certain Knowledge / 5. Cogito Critique

19459

To say 'I am not thinking' must be false, but it might have been true, so it isn't self-contradictory

19460

'I know I exist' has no counterevidence, so it may be meaningless

19461

Knowing I exist reveals nothing at all about my nature

11. Knowledge Aims / C. Knowing Reality / 2. Phenomenalism

6525	Logical positivists could never give the sense-data equivalent of 'there is a table next door' [Robinson,H]

5170	Material things are constructions from actual and possible occurrences of sense-contents

8824	No one has defended translational phenomenalism since Ayer in 1940 [Kim]

2614	Modern phenomenalism holds that objects are logical constructions out of sense-data

12. Knowledge Sources / A. A Priori Knowledge / 4. A Priori as Necessities

5198	We could verify 'a thing can't be in two places at once' by destroying one of the things [Ierubino]

12. Knowledge Sources / A. A Priori Knowledge / 5. A Priori Synthetic

2619	Whether geometry can be applied to reality is an empirical question outside of geometry

12. Knowledge Sources / A. A Priori Knowledge / 7. A Priori from Convention

5197	By changing definitions we could make 'a thing can't be in two places at once' a contradiction

12. Knowledge Sources / A. A Priori Knowledge / 8. A Priori as Analytic

5204	To say that a proposition is true a priori is to say that it is a tautology

12. Knowledge Sources / B. Perception / 4. Sense Data / a. Sense-data theory

6524	Positivists prefer sense-data to objects, because the vocabulary covers both illusions and perceptions [Robinson,H]

2615	The concept of sense-data allows us to discuss appearances without worrying about reality

12. Knowledge Sources / B. Perception / 7. Causal Perception

5193	Causal and representative theories of perception are wrong as they refer to unobservables

12. Knowledge Sources / C. Rationalism / 1. Rationalism

5200	The main claim of rationalism is that thought is an independent source of knowledge

12. Knowledge Sources / D. Empiricism / 1. Empiricism

4729	Empiricism lacked a decent account of the a priori, until Ayer said it was entirely analytic [O'Grady]

5180	All propositions (especially 'metaphysics') must begin with the senses

5169	My empiricism logically distinguishes analytic and synthetic propositions, and metaphysical verbiage

12. Knowledge Sources / D. Empiricism / 4. Pro-Empiricism

5185	It is further sense-experience which informs us of the mistakes that arise out of sense-experience

12. Knowledge Sources / D. Empiricism / 5. Empiricism Critique

5199	Empiricism, it is said, cannot account for our knowledge of necessary truths

13. Knowledge Criteria / B. Internal Justification / 4. Foundationalism / c. Empirical foundations

5163	Basic propositions refer to a single experience, are incorrigible, and conclusively verifiable

14. Science / A. Basis of Science / 6. Falsification

19464

We only discard a hypothesis after one failure if it appears likely to keep on failing

14. Science / C. Induction / 2. Aims of Induction

5190	The induction problem is to prove generalisations about the future based on the past

19462

Induction passes from particular facts to other particulars, or to general laws, non-deductively

14. Science / C. Induction / 3. Limits of Induction

5191	We can't use the uniformity of nature to prove induction, as that would be circular

15. Nature of Minds / A. Nature of Mind / 4. Other Minds / b. Scepticism of other minds

5177	Other minds are 'metaphysical' objects, because I can never observe their experiences

5662	Maybe induction could never prove the existence of something unobservable

15. Nature of Minds / A. Nature of Mind / 4. Other Minds / c. Knowing other minds

5178	A conscious object is by definition one that behaves in a certain way, so behaviour proves consciousness

5167	The argument from analogy fails, so the best account of other minds is behaviouristic

5328	Originally I combined a mentalistic view of introspection with a behaviouristic view of other minds

5330	Physicalism undercuts the other mind problem, by equating experience with 'public' brain events

2613	The theory of other minds has no rival

16. Persons / B. Nature of the Self / 1. Self and Consciousness

5664	Consciousness must involve a subject, and only bodies identify subjects

16. Persons / B. Nature of the Self / 5. Self as Associations

5172	If the self is meaningful, it must be constructed from sense-experiences

5325	Is something an 'experience' because it relates to other experiences, or because it relates to a subject?

5326	Qualia must be united by a subject, because they lead to concepts and judgements

16. Persons / B. Nature of the Self / 7. Self and Body / a. Self needs body

5173	Two experiences belong to one self if their contents belong with one body

5176	Empiricists can define personal identity as bodily identity, which consists of sense-contents

5668	People own conscious states because they are causally related to the identifying body

5324	Bodily identity and memory work together to establish personal identity

16. Persons / C. Self-Awareness / 2. Knowing the Self

5322	Self-consciousness is not basic, because experiences are not instrinsically marked with ownership

16. Persons / C. Self-Awareness / 3. Limits of Introspection

5661	We identify experiences by their owners, so we can't define owners by their experiences

16. Persons / D. Continuity of the Self / 2. Mental Continuity / a. Memory is Self

5665	Memory is the best proposal as what unites bundles of experiences

5666	Not all exerience can be remembered, as this would produce an infinite regress

16. Persons / D. Continuity of the Self / 2. Mental Continuity / c. Inadequacy of mental continuity

5327	Temporal gaps in the consciousness of a spirit could not be bridged by memories

16. Persons / D. Continuity of the Self / 6. Body sustains Self

5669	Personal identity can't just be relations of experiences, because the body is needed to identify them

17. Mind and Body / A. Mind-Body Dualism / 8. Dualism of Mind Critique

5171	The supposed 'gulf' between mind and matter is based on the senseless concept of 'substances'

17. Mind and Body / E. Mind as Physical / 1. Physical Mind

5329	Why shouldn't we say brain depends on mind? Better explanation!

19. Language / A. Nature of Meaning / 5. Meaning as Verification

5181	A sentence is factually significant to someone if they know how to verify its proposition

5184	Factual propositions imply (in conjunction with a few other premises) possible experiences

5186	Tautologies and empirical hypotheses form the entire class of significant propositions

5164	A statement is meaningful if observation statements can be deduced from it

5165	Directly verifiable statements must entail at least one new observation statement

5166	The principle of verification is not an empirical hypothesis, but a definition

19. Language / D. Propositions / 1. Propositions

5162	Sentences only express propositions if they are meaningful; otherwise they are 'statements'

19. Language / D. Propositions / 6. Propositions Critique

2610	Talk of propositions is just shorthand for talking about equivalent sentences

22. Metaethics / A. Ethics Foundations / 1. Nature of Ethics / b. Defining ethics

6968	Some people think there are ethical facts, but of a 'queer' sort

6972	A right attitude is just an attitude one is prepared to stand by

22. Metaethics / A. Ethics Foundations / 1. Nature of Ethics / d. Ethical theory

6973	Moral theories are all meta-ethical, and are neutral as regards actual conduct

6974	Moral judgements cannot be the logical consequence of a moral philosophy

22. Metaethics / A. Ethics Foundations / 2. Source of Ethics / c. Ethical intuitionism

5205	Moral intuition is worthless if there is no criterion to decide between intuitions

6971	I would describe intuitions of good as feelings of approval

22. Metaethics / A. Ethics Foundations / 2. Source of Ethics / h. Expressivism

23725

Ayer defends the emotivist version of expressivism [Smith,M]

5206	To say an act is wrong makes no further statement about it, but merely expresses disapproval

6969	Approval of historical or fictional murders gives us leave to imitate them

6970	Moral judgements are not expressions, but are elements in a behaviour pattern

22. Metaethics / A. Ethics Foundations / 2. Source of Ethics / i. Prescriptivism

5168	Moral approval and disapproval concerns classes of actions, rather than particular actions

26. Natural Theory / C. Causation / 9. General Causation / d. Causal necessity

15251

The attribution of necessity to causation is either primitive animism, or confusion with logical necessity

28. God / A. Divine Nature / 4. Divine Contradictions

5208	A person with non-empirical attributes is unintelligible.

28. God / B. Proving God / 2. Proofs of Reason / b. Ontological Proof critique

5187	When we ascribe an attribute to a thing, we covertly assert that it exists

28. God / C. Attitudes to God / 5. Atheism

5207	If theism is non-sensical, then so is atheism.

29. Religion / D. Religious Issues / 1. Religious Commitment / c. Religious Verification

5209	The 'truths' expressed by theists are not literally significant