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Ideas of A.J. Ayer, by Text

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

1936 Language,Truth and Logic
p.15 Humeans rejected the a priori synthetic, and so rejected even Kantian metaphysics
     Full Idea: Thinkers from Hume to the logical positivists took exception to Kant's view that some synthetic propositions could be known a priori, and so rejected the possibility of metaphysics as Kant conceived of it.
     From: report of A.J. Ayer (Language,Truth and Logic [1936]) by Cynthia Macdonald - Varieties of Things Ch.1
     A reaction: See Idea 7918 for Kant's epistemological view of metaphysics. This strikes me as a big misunderstanding by empiricists, even though they are quite right to insist on evidence and proof. Metaphysics is essential, but its excess is the worst nonsense.
p.123 Empiricism lacked a decent account of the a priori, until Ayer said it was entirely analytic
     Full Idea: Ayer's gives an account of the a priori (as analytic) that readily meshes with empiricism, and empiricism had long been lacking an adequate account of the a priori
     From: comment on A.J. Ayer (Language,Truth and Logic [1936]) by Paul O'Grady - Relativism Ch.4
     A reaction: Ayer's logical positivist view was based on Hume's 'relations of ideas', as opposed to 'matters of fact'. Personally I see no reason why some facts about reality shouldn't be self-evident to thought, just as others are self-evident to the senses.
p.227 Positivists prefer sense-data to objects, because the vocabulary covers both illusions and perceptions
     Full Idea: Positivists prefer the sense-datum vocabulary because it is more inclusive than physical object vocabulary; it can report after-images, hallucinations, illusions and bodily sensations, as well as veridical perceptions.
     From: report of A.J. Ayer (Language,Truth and Logic [1936]) by Howard Robinson - Perception IX.4
     A reaction: The assumption of this is that illusions and perceptions are frequently indistinguishable, but that is just nonsense. Illusions usually appeal to one sense only, when you are ill, and in an unclear way. Sensible people know objects when they see them.
p.227 Logical positivists could never give the sense-data equivalent of 'there is a table next door'
     Full Idea: Logical positivist phenomenalism has few supporters these days; ..no one ever seemed clear what the sense-datum equivalent of 'there is a table in the next room' could be.
     From: comment on A.J. Ayer (Language,Truth and Logic [1936]) by Howard Robinson - Perception IX.4
     A reaction: But do the critics know what they mean by 'there is a table in the next room'? Does it just mean 'I am hoping there is'? You can't refer to the table in the next room without sticking your ontological neck out - and that is 'best explanation'.
p.227 Positivists regard ontology as either meaningless or stipulated
     Full Idea: Positivists tend to be prejudiced against ontology, regarding very general questions about what sort of things exist either as meaningless, or as questions to be settled by stipulation.
     From: report of A.J. Ayer (Language,Truth and Logic [1936]) by Howard Robinson - Perception IX.4
     A reaction: So much the worse for positivists, because they are missing all the fun. I consider one of the central activities of philosophy to be speculating about explanations. Ontology is at the heart of what explanation aims at.
Ch.1 p.45 Philosophy deals with the questions that scientists do not wish to handle
     Full Idea: If there are any questions which science leaves it to philosophy to answer, a straightforward process of elimination must lead to their discovery.
     From: A.J. Ayer (Language,Truth and Logic [1936], Ch.1)
     A reaction: This is characteristic of the feeble-mindedness that British philosophy slipped into in the age of Wittgenstein, and for a while thereafter. Personally I regard scientists as servants, who are sent off on exploratory errands, and must report back.
Ch.1 p.45 All propositions (especially 'metaphysics') must begin with the senses
     Full Idea: One way to attack a metaphysician would be to enquire from what premises his propositions were deduced. Must he not begin, as other men do, with the evidence of his senses?
     From: A.J. Ayer (Language,Truth and Logic [1936], Ch.1)
     A reaction: This simple idea is the core of empiricism. This is a heavily criticised doctrine, but you must start somewhere. Hume and Russell agreed. Don't forget, though, that Descartes's first move is to reject the senses as untrustworthy.
Ch.1 p.48 A sentence is factually significant to someone if they know how to verify its proposition
     Full Idea: A sentence is factually significant to any given person, if, and only if, he knows how to verify the proposition which it purports to express.
     From: A.J. Ayer (Language,Truth and Logic [1936], Ch.1)
     A reaction: 'I can't verify it, but I know a bloke who can'? 'If only I could think of a way to verify x'? 'This is unverifiable, but it is the only remaining possibility'? 'X is unverifiable, but it would nice if it was true'? Etc.
Ch.1 p.51 Only tautologies can be certain; other propositions can only be probable
     Full Idea: No proposition, other than a tautology, can possibly be anything more than a probable hypothesis.
     From: A.J. Ayer (Language,Truth and Logic [1936], Ch.1)
     A reaction: A nice clear empiricist rejection of all attempts to assert necessary truths about nature. This also seems to be a rejection of empiricist foundationalism. A problem case seems to be introspective observations, which seem irrefutable and obvious.
Ch.1 p.52 Factual propositions imply (in conjunction with a few other premises) possible experiences
     Full Idea: The mark of a genuinely factual proposition is that some experiential propositions can be deduced from it in conjunction with certain other premises without being deducible from those premises alone.
     From: A.J. Ayer (Language,Truth and Logic [1936], Ch.1)
     A reaction: I.Berlin showed that any statement S could pass this test, because if you assert 'S' and 'If S then O', these two statements entail O, which could be some random observation. Verificationism kept meeting problems of this kind.
Ch.1 p.53 It is further sense-experience which informs us of the mistakes that arise out of sense-experience
     Full Idea: It is further sense-experience which informs us of the mistakes that arise out of sense-experience.
     From: A.J. Ayer (Language,Truth and Logic [1936], Ch.1)
     A reaction: This is a wonderfull plain-spoken challenge to anyone who thinks they can demonstrate facts a priori about reality. 'I see this object in two places at once'? 'This object appears to be both red and green'?
Ch.1 p.56 Tautologies and empirical hypotheses form the entire class of significant propositions
     Full Idea: Tautologies and empirical hypotheses form the entire class of significant propositions.
     From: A.J. Ayer (Language,Truth and Logic [1936], Ch.1)
     A reaction: This appears to be false. Possibly the problem is that Ayer takes the whole proposition to be the unit of meaning, but actually meaninfulness only requires that we build up a claim about a possible world from semantic units. Blue bees live on square suns.
Ch.1 p.58 When we ascribe an attribute to a thing, we covertly assert that it exists
     Full Idea: When we ascribe an attribute to a thing, we covertly assert that it exists.
     From: A.J. Ayer (Language,Truth and Logic [1936], Ch.1)
     A reaction: This is an unsurprising endorsement from logical positivism that Kant's claim that the ontological argument is probably tautological is correct. We could of course say "Imagine a non-existent being with dirty toenails".
Ch.2 p.65 Philosophers should abandon speculation, as philosophy is wholly critical
     Full Idea: We can overthrow speculative philosophy, and see that the function of philosophy is wholly critical.
     From: A.J. Ayer (Language,Truth and Logic [1936], Ch.2)
     A reaction: This seems to imply that we CAN speculate, which appeared to be rendered impossible by the verification principle. Personally I think speculation is central to philosophy, but Ayer should always stand as a warning against bogus truth-claims.
Ch.2 p.66 The induction problem is to prove generalisations about the future based on the past
     Full Idea: The problem of induction is (roughly) finding a way to prove that certain empirical generalisations which are derived from past experience will hold good also in the future.
     From: A.J. Ayer (Language,Truth and Logic [1936], Ch.2)
     A reaction: This doesn't seem to be the only problem. It seems self-evident (since Hume) that you cannot use deductive reasoning to prove that the future will be like the past. In fact, we should obviously be cautious, as things could easily change.
Ch.2 p.66 We can't use the uniformity of nature to prove induction, as that would be circular
     Full Idea: It is often said that we can justify induction by invoking the uniformity of nature, but that principle merely states (in a misleading fashion) the assumption that past experience is a reliable guide to the future.
     From: A.J. Ayer (Language,Truth and Logic [1936], Ch.2)
     A reaction: That is correct, but it seems to me that if you take the uniformity of nature as a provisional unproven axiom, then induction is an account of how rational creatures cope with the situation. If nature ceases to be uniform, our reason cannot cope.
Ch.2 p.71 Causal and representative theories of perception are wrong as they refer to unobservables
     Full Idea: The fact that all causal and representative theories of perception treat material things as if they were unobservable entities entitles us to rule them out a priori.
     From: A.J. Ayer (Language,Truth and Logic [1936], Ch.2)
     A reaction: It seems to me that we can accept a causal/representative account of perception if we think of it in terms of 'best explanation' rather than observables. Explanation requires speculation, which logical positivists can't cope with.
Ch.2 p.75 Critics say analysis can only show the parts, and not their distinctive configuration
     Full Idea: Critics say an analyst is obliged by his atomistic metaphysics to regard an object consisting of parts a, b, c and d in a distinctive configuration as being simply a+b+c+d, and thus giving an entirely false account of its nature.
     From: A.J. Ayer (Language,Truth and Logic [1936], Ch.2)
     A reaction: Ayer refers the critics to gestatl psychology. Personally I prefer to talk about the ontology rather than the psychology. If we include (as Russell suggests) relations as part of the analysis, there seems to be no problem.
Ch.2 p.76 Philosophy is a department of logic
     Full Idea: Philosophy is a department of logic.
     From: A.J. Ayer (Language,Truth and Logic [1936], Ch.2)
     A reaction: Personally I would invert that. Philosophy is concerned with human rationality, of which precise logic appears to be a rather limited subdivision. I see philosophy as the 'master' subject, not the 'servant' subject (as Locke had implied).
Ch.2 p.77 We could verify 'a thing can't be in two places at once' by destroying one of the things
     Full Idea: It is possible to challenge the proposition 'a material thing cannot be in two places at once' empirically; if you destroy one object, the other should also instantly be destroyed if they are a single thing.
     From: comment on A.J. Ayer (Language,Truth and Logic [1936], Ch.2) by Virgil Ierubino - works
     A reaction: This leaves us having to decide whether the proposition is metaphysically necessary, or is empirical, or is tautological. This idea inclines me towards the view that it is empirical. Imagine two 'separate' objects which responded identically to stimuli.
Ch.2 p.77 By changing definitions we could make 'a thing can't be in two places at once' a contradiction
     Full Idea: The proposition that 'a material thing cannot be in two places at once' is not empirical at all, but linguistic; ..we could so alter our definitions that the proposition came to express a self-contradiction instead of a necessary truth.
     From: A.J. Ayer (Language,Truth and Logic [1936], Ch.2)
     A reaction: This seems a striking anticipation of Quine's famous challenge to the analytic/synthetic distinction.
Ch.4 p.96 Empiricism, it is said, cannot account for our knowledge of necessary truths
     Full Idea: The objection which is commonly brought against empiricism is that it is impossible on empiricist principles to account for our knowledge of necessary truths.
     From: A.J. Ayer (Language,Truth and Logic [1936], Ch.4)
     A reaction: This criticism goes back at least to Leibniz. Ayer's distinctive contribution to empiricism (with help) is to emphasise that we can only know necessities if they are tautologies. Hume always challenged our knowledge of natural necessities.
Ch.4 p.98 The main claim of rationalism is that thought is an independent source of knowledge
     Full Idea: The fundamental tenet of rationalism is that thought is an independent source of knowledge.
     From: A.J. Ayer (Language,Truth and Logic [1936], Ch.4)
     A reaction: Presumably one should add that thought gives synthetic knowledge. Thought is also an experience, so empiricists will always acknowledge that we could have some knowledge (of thought) by thought alone.
Ch.4 p.103 Maths and logic are true universally because they are analytic or tautological
     Full Idea: The principles of logic and mathematics are true universally simply because we never allow them to be anything else; …in other words, they are analytic propositions, or tautologies.
     From: A.J. Ayer (Language,Truth and Logic [1936], Ch.4)
     A reaction: This is obviously a very appealing idea, but it doesn's explain WHY we have invented these particular tautologies (which seem surprisingly useful). The 'science of patterns' can be empirical and a priori and useful (but not tautological).
Ch.4 p.110 Whether geometry can be applied to reality is an empirical question outside of geometry
     Full Idea: Whether a geometry can be applied to the actual physical world or not, is an empirical question which falls outside the scope of the geometry itself.
     From: A.J. Ayer (Language,Truth and Logic [1936], Ch.4)
     A reaction: This is a key objection to rationalism by empiricists. You may say that geometry applies to your car, but your car may have been pulverised while you were talking. Why, though, did Einstein find non-Euclidean geometry so useful?
Ch.4 p.115 To say that a proposition is true a priori is to say that it is a tautology
     Full Idea: To say that a proposition is true a priori is to say that it is a tautology.
     From: A.J. Ayer (Language,Truth and Logic [1936], Ch.4)
     A reaction: This is Ayer's splendidly clearcut anti-rationalism. However, one might concede that one cannot know a priori about remote possible worlds (though I'm not so sure), but still claim a priori extrapolations from our current experiences.
Ch.5 p.118 We cannot analyse the concept of 'truth', because it is simply a mark that a sentence is asserted
     Full Idea: When one says that "Queen Anne is dead" is true or false, these terms 'true' and 'false' connote nothing, but function in the sentence simply as marks of assertion and denial, so there is no sense in asking us to analyse the concept of 'truth'.
     From: A.J. Ayer (Language,Truth and Logic [1936], Ch.5)
     A reaction: "I am ill" may be true when you say it, and false when I say it. The word 'true' has a useful function in 'x is true if y'. "If that is true, Freddie, I will hit you".
Ch.6 p.17 Ayer defends the emotivist version of expressivism
     Full Idea: Ayer defends emotivism, which is his own favoured form of expressivism.
     From: report of A.J. Ayer (Language,Truth and Logic [1936], Ch.6) by Michael Smith - The Moral Problem 2.1
     A reaction: A helpful distinction of terminology. Expressivism is the broad theory, and emotivism is a sub-type, saying that it is emotions which are expressed. The alternative (such as Prescriptivism) is to express pro- and con- attitudes.
Ch.6 p.141 Moral intuition is worthless if there is no criterion to decide between intuitions
     Full Idea: Unless it is possible to provide some criterion by which one may decide between conflicting intuitions, a mere appeal to intuition is worthless as a test of a proposition's validity.
     From: A.J. Ayer (Language,Truth and Logic [1936], Ch.6)
     A reaction: It is a bit much to expect a 'proof' of its 'validity'! If moral judgements are reflected in consequences, then reliable intuitions (i.e. wisdom) could be demonstrated by getting it right (for happiness, or flourishing).
Ch.6 p.142 To say an act is wrong makes no further statement about it, but merely expresses disapproval
     Full Idea: In adding 'You acted wrongly in…' to 'you stole my money' I am not making any further statement about it; I am simply evincing my moral disapproval of it.
     From: A.J. Ayer (Language,Truth and Logic [1936], Ch.6)
     A reaction: A basic claim of emotivism. Perhaps an understandable response to (e.g.) Kantian claims that we have duties, but to no one in particular. Most people mean by moral criticism that there will be long-term bad consequences, or virtue is lacking.
Ch.6 p.153 If theism is non-sensical, then so is atheism.
     Full Idea: If the assertion that there is a god is non-sensical, then the atheist's assertion that there is no god is equally non-sensical.
     From: A.J. Ayer (Language,Truth and Logic [1936], Ch.6)
     A reaction: Ayer urgently needs the concept of 'best explanation'. If we observe only footprints, we infer creatures; if there are no footprints, lack of creatures looks like a good theory. The design argument is perfectly meaningful.
Ch.6 p.154 A person with non-empirical attributes is unintelligible.
     Full Idea: The notion of a person whose essential attributes are non-empirical is not an intelligible notion at all.
     From: A.J. Ayer (Language,Truth and Logic [1936], Ch.6)
     A reaction: Non-empirical and non-causal are not quite the same thing. A being which never had any effects is a bizarre, and probably pointless, fantasy. A being which affected our world (through ideas, say) but is unobservable is a perfectly good theory.
Ch.6 p.155 The 'truths' expressed by theists are not literally significant
     Full Idea: There cannot be any transcendent truths of religion, for the sentences which the theist uses to express such 'truths' are not literally significant.
     From: A.J. Ayer (Language,Truth and Logic [1936], Ch.6)
     A reaction: Ayer claims that only tautologies or empirically verifiable statements have literal significance. I say speculations, wild theories and fantasies are perfectly meaningful. Nevertheless, the words of many hymns and prayers look like empty rhetoric.
Ch.7 p.161 My empiricism logically distinguishes analytic and synthetic propositions, and metaphysical verbiage
     Full Idea: The empiricist doctrine to which we are committed is a logical doctrine concerning the distinction between analytic propositions, synthetic propositions, and metaphysical verbiage.
     From: A.J. Ayer (Language,Truth and Logic [1936], Ch.7)
     A reaction: This is the tough logical positivist version of empiricism. The whole project stumbles on the relationship between a synthetic proposition and its verifying experiences. How close? What of wild speculations? The analytic part is interesting, though.
Ch.7 p.162 Material things are constructions from actual and possible occurrences of sense-contents
     Full Idea: The existence of a material thing is defined in terms of the actual and possible occurrence of the sense-contents which constitute it as a logical construction.
     From: A.J. Ayer (Language,Truth and Logic [1936], Ch.7)
     A reaction: Obviously we need 'possible' experiences so that unperceived trees can still exist, but it is a can of worms. Is speculation about a possible world an account of possible experiences? Realists want to know WHY we think certain experiences are possible.
Ch.7 p.164 The supposed 'gulf' between mind and matter is based on the senseless concept of 'substances'
     Full Idea: The problems of bridging the 'gulf' between mind and matter, in knowledge or in action, are all fictitious problems arising out of the senseless metaphysical conception of mind and matter as 'substances'.
     From: A.J. Ayer (Language,Truth and Logic [1936], Ch.7)
     A reaction: He is presumably implying that there is only one 'substance', the stuff of physics, thus voting for Spinoza's dual aspect theory. There could still be a 'gulf', between incommensurable properties, or untranslatable levels of description.
Ch.7 p.165 If the self is meaningful, it must be constructed from sense-experiences
     Full Idea: The self, if it is not to be treated as a metaphysical entity, must be held to be a logical construction out of sense-experiences.
     From: A.J. Ayer (Language,Truth and Logic [1936], Ch.7)
     A reaction: It is striking how people differ in their reports when they try to see the self by introspection. The self could be beyond sense-experience, and yet still be the best explanation of what we actually DO experience. It is a 'transcendental sensation'?
Ch.7 p.165 Two experiences belong to one self if their contents belong with one body
     Full Idea: For any two sense-experiences to belong to the sense-history of the same self it is necessary and sufficient that they should contain organic sense-contents which are elements of the same body.
     From: A.J. Ayer (Language,Truth and Logic [1936], Ch.7)
     A reaction: This makes more sense if you are a realist about organic bodies, but less sense if (like Ayer) you define the body in terms of sense-experiences. It is a stab at what is now called 'animalism', but needs an account of brain transplant thought-experiments.
Ch.7 p.168 Empiricists can define personal identity as bodily identity, which consists of sense-contents
     Full Idea: We have solved Hume's problem by defining personal identity in terms of bodily identity, and bodily identity is to be defined in terms of the resemblance and continuity of sense-contents.
     From: A.J. Ayer (Language,Truth and Logic [1936], Ch.7)
     A reaction: This is a phenomenalist account of personal identity, so it has no independent account of the body apart from the contents of the mind. Personally I think we must distinguish 'central' mental events from 'peripheral' ones.
Ch.7 p.170 Other minds are 'metaphysical' objects, because I can never observe their experiences
     Full Idea: On the view that we are discussing, I must regard other people as metaphysical objects; for it is assumed that their experiences are completely inaccessible to my observation.
     From: A.J. Ayer (Language,Truth and Logic [1936], Ch.7)
     A reaction: 'Metaphysical' is here a dirty word. This is the strictly empirical view of other minds, which pushes Ayer towards behaviourism on this subject. He should have asked about the 'best explanation' of the behaviour of others'.
Ch.7 p.172 A conscious object is by definition one that behaves in a certain way, so behaviour proves consciousness
     Full Idea: If I know that an object behaves in every way as a conscious being must, by definition, behave, then I know that it is really conscious. This is an analytical proposition.
     From: A.J. Ayer (Language,Truth and Logic [1936], Ch.7)
     A reaction: This treats the Turing test as proof of consciousness, and is open to all the usual objections to behaviourism. To say behaviour IS consciousness is ridiculous. It just counts as evidence. Presumably Ayer would later have become a functionalist.
1940 The Foundations of Empirical Knowledge
p.303 No one has defended translational phenomenalism since Ayer in 1940
     Full Idea: I know of no serious defence of 'translational phenomenalism' since Ayer's in 1940.
     From: report of A.J. Ayer (The Foundations of Empirical Knowledge [1940]) by Jaegwon Kim - What is 'naturalized epistemology'? 303-4+n
     A reaction: We can think of Ayer as a hero who explored how far extreme empiricism would go. We still have anti-realists who are singing from a revised version of the song-sheet. Personally I am with Russell, that we must embrace the best explanation.
IV.18 p.186 The attribution of necessity to causation is either primitive animism, or confusion with logical necessity
     Full Idea: How are we to explain the word 'must' [about causation]? The answer is, I think, that it is either a relic of animism, or else reveals an inclination to treat causal connexion as if it were a form of logical necessity.
     From: A.J. Ayer (The Foundations of Empirical Knowledge [1940], IV.18)
     A reaction: The animism proposal just about makes sense (as a primitive feature of minds), but why would anyone, if they had the time and understanding, dream of treating a regular connection as a 'logical' necessity?
1946 Introduction to 'Language Truth and Logic'
p.10 p.10 Sentences only express propositions if they are meaningful; otherwise they are 'statements'
     Full Idea: I suggest that every grammatically significant indicative sentence expresses a 'statement', but the word 'proposition' will be reserved for what is expressed by sentences that are literally meaningful.
     From: A.J. Ayer (Introduction to 'Language Truth and Logic' [1946], p.10)
     A reaction: We don't have to accept Ayer's over-fussy requirements for what is meaningful to accept that this is a good distinction. Every day we hear statements from people (e.g. politicians) in which we can fish in vain for the underlying proposition.
p.13 p.13 Basic propositions refer to a single experience, are incorrigible, and conclusively verifiable
     Full Idea: There is a class of empirical propositions, which I call 'basic propositions', which can be verified conclusively, since they refer solely to the contents of a single experience, which are incorrigible.
     From: A.J. Ayer (Introduction to 'Language Truth and Logic' [1946], p.13)
     A reaction: A classic statement of empirical foundationalism. I sort of agree that 'single experiences' are a 'given' for philosophy, but is questionable whether there is anything which could both be a single experience AND give rise to a proposition.
p.15 p.15 A statement is meaningful if observation statements can be deduced from it
     Full Idea: In the improved version, a statement was verifiable, and consequently meaningful, if 'some observation-statement can be deduced from it in conjunction with certain other premises, without being deducible from those other premises alone'.
     From: A.J. Ayer (Introduction to 'Language Truth and Logic' [1946], p.15)
     A reaction: I.Berlin showed that any statement S could pass this test, because if you assert 'S' and 'If S then O', these two statements entail O, which could be some random observation. Hence a 1946 revised version had to be produced.
p.17 p.17 Directly verifiable statements must entail at least one new observation statement
     Full Idea: A statement is directly verifiable if it is either itself an observation-statement,or is such that in conjunction with one or more observation-statements it entails at least one observation-statement which is not deducible from these other premises alone.
     From: A.J. Ayer (Introduction to 'Language Truth and Logic' [1946], p.17)
     A reaction: This is the 1946 revised version of the Verification Principle, which was then torpedoed by an elaborate counterexample from Alonzo Church. Ayer thereafter abandoned attempts to find a precise statement of it.
p.21 p.21 The principle of verification is not an empirical hypothesis, but a definition
     Full Idea: I wish the principle of verification to be regarded, not as an empirical hypothesis, but as a definition.
     From: A.J. Ayer (Introduction to 'Language Truth and Logic' [1946], p.21)
     A reaction: This is Ayer's attempt to meet the well known objection of 'turning the tables' on his theory (by asking whether it is tautological or empirically verifiable). However, if it is just a definition, then presumably it is completely arbitrary…
p.26 p.26 The argument from analogy fails, so the best account of other minds is behaviouristic
     Full Idea: There are too many objections to the argument from analogy, so I am inclined to revert to a 'behaviouristic' interpretation of propositions about other people's experiences.
     From: A.J. Ayer (Introduction to 'Language Truth and Logic' [1946], p.26)
     A reaction: It seems odd to vote for behaviourism on one issue, if you aren't a general subscriber. It is one thing to say that behaviour is the best evidence for your explanation, quite another to equate the other mind with its behaviour.
p.27 p.27 Moral approval and disapproval concerns classes of actions, rather than particular actions
     Full Idea: The common objects of moral approval and disapproval are not particular actions so much as classes of actions.
     From: A.J. Ayer (Introduction to 'Language Truth and Logic' [1946], p.27)
     A reaction: This 1946 revision of his pure emotivism looks like a move towards Hare's prescriptivism, where classes, rules and principles are seen as the window-dressing of emotivism. It's still a bad theory.
1947 Phenomenalism
§1 p.125 Modern phenomenalism holds that objects are logical constructions out of sense-data
     Full Idea: Nowadays phenomenalism is held to be a theory of perception which says that physical objects are logical constructions out of sense-data.
     From: A.J. Ayer (Phenomenalism [1947], §1)
§1 p.131 The concept of sense-data allows us to discuss appearances without worrying about reality
     Full Idea: The introduction of the term 'sense-datum' is a means of referring to appearances without prejudging the question of what it is, if anything, that they are appearances of.
     From: A.J. Ayer (Phenomenalism [1947], §1)
1949 On the analysis of moral judgements
p.246 Moral theories are all meta-ethical, and are neutral as regards actual conduct
     Full Idea: All moral theories, intuitionist, naturalistic, objectivist, emotive, and the rest, in so far as they are philosophical theories, are neutral as regards actual conduct; they belong to the field of meta-ethics, not ethics proper.
     From: A.J. Ayer (On the analysis of moral judgements [1949])
     A reaction: Interestingly, Ayer doesn't seem willing to accept 'ethics proper' as being 'philosophical'. Given the modern rise of applied ethics, it seems suprising to say that even normative ethics is not philosophical. Utilitarianism seems not to be philosophical.
p.233 p.233 Some people think there are ethical facts, but of a 'queer' sort
     Full Idea: If someone wishes to say that ethical statements are statements of fact, only it is a queer sort of fact, he is welcome to do so.
     From: A.J. Ayer (On the analysis of moral judgements [1949], p.233)
     A reaction: The word 'queer' was picked up by Mackie and developed into his error theory, that moral facts are a misunderstanding. Personally I think that moral facts might be teleological facts, but that is rather hard to demonstrate.
p.237 p.237 Approval of historical or fictional murders gives us leave to imitate them
     Full Idea: In saying that Brutus or Raskolnikov acted rightly, I am giving myself and others leave to imitate them should similar circumstances arise.
     From: A.J. Ayer (On the analysis of moral judgements [1949], p.237)
     A reaction: This seems to be a reply to the Frege-Geach Problem, of why we have emotional attitudes to crimes that mean nothing to us. Such crimes, however, involve our virtues, and don't depend on awaiting 'similar circumstances'.
p.238 p.238 Moral judgements are not expressions, but are elements in a behaviour pattern
     Full Idea: To say, as I once did, that moral judgements are merely expressive of certain feelings is an oversimplification; ..moral attitudes consist in certain patterns of behaviour, and the expression of a judgement is an element in the pattern.
     From: A.J. Ayer (On the analysis of moral judgements [1949], p.238)
     A reaction: This seems to switch from emotivism to what Frank Jackson calls 'moral functionalism', where morality is what gets us from certain emotional responses to willed actions. This strikes me, like most functional explanations, as wrong.
p.239 p.239 I would describe intuitions of good as feelings of approval
     Full Idea: I suspect that the experiences which some philosophers want to describe as intuitions, or a quasi-sensory apprehensions, of good are not significantly different from those that I want to describe as feelings of approval.
     From: A.J. Ayer (On the analysis of moral judgements [1949], p.239)
     A reaction: This is the standard ground for rejecting intuitionism, along with the point that even if intuitions are not just feelings of approval, it seems impossible to tell the difference.
p.244 p.244 A right attitude is just an attitude one is prepared to stand by
     Full Idea: Asking whether the attitude that one has adopted is the right attitude comes down to asking whether one is prepared to stand by it.
     From: A.J. Ayer (On the analysis of moral judgements [1949], p.244)
     A reaction: I would have thought that someone who persisted in being ruthlessly selfish might nevertheless distinguish their behaviour from the grudging concession that the 'right' thing to do might be quite different.
p.247 p.247 Moral judgements cannot be the logical consequence of a moral philosophy
     Full Idea: A moral philosopher will have his moral standards and will sometimes make moral judgements, but these moral judgements cannot be a logical consequence of his philosophy.
     From: A.J. Ayer (On the analysis of moral judgements [1949], p.247)
     A reaction: I take this to be an assertion of the is-ought distinction. Personally this strikes me as totally false. Ayer needs to think more deeply about moral philosophy!
1956 The Problem of Knowledge
2.iii p.45 To say 'I am not thinking' must be false, but it might have been true, so it isn't self-contradictory
     Full Idea: To say 'I am not thinking' is self-stultifying since if it is said intelligently it must be false: but it is not self-contradictory. The proof that it is not self-contradictory is that it might have been false.
     From: A.J. Ayer (The Problem of Knowledge [1956], 2.iii)
     A reaction: If it doesn't imply a contradiction, then it is not a necessary truth, which is what it is normally taken to be. Is 'This is a sentence' necessarily true? It might not have been one, if the rules of English syntax changed recently.
2.iii p.48 'I know I exist' has no counterevidence, so it may be meaningless
     Full Idea: If there is no experience at all of finding out that one is not conscious, or that one does not exist, ..it is tempting to say that sentences like 'I exist', 'I am conscious', 'I know that I exist' do not express genuine propositions.
     From: A.J. Ayer (The Problem of Knowledge [1956], 2.iii)
     A reaction: This is, of course, an application of the somewhat discredited verification principle, but the fact that strictly speaking the principle has been sort of refuted does not mean that we should not take it seriously, and be influenced by it.
2.iii p.52 Knowing I exist reveals nothing at all about my nature
     Full Idea: To know that one exists is not to know anything about oneself any more than knowing that 'this' exists is knowing anything about 'this'.
     From: A.J. Ayer (The Problem of Knowledge [1956], 2.iii)
     A reaction: Descartes proceeds to define himself as a 'thinking thing', inferring that thinking is his essence. Ayer casts nice doubt on that.
2.viii p.7 Induction assumes some uniformity in nature, or that in some respects the future is like the past
     Full Idea: In all inductive reasoning we make the assumption that there is a measure of uniformity in nature; or, roughly speaking, that the future will, in the appropriate respects, resemble the past.
     From: A.J. Ayer (The Problem of Knowledge [1956], 2.viii)
     A reaction: I would say that nature is 'stable'. Nature changes, so a global assumption of total uniformity is daft. Do we need some global uniformity assumptions, if the induction involved is local? I would say yes. Are all inductions conditional on this?
2.viii p.72 Induction passes from particular facts to other particulars, or to general laws, non-deductively
     Full Idea: Inductive reasoning covers all cases in which we pass from a particular statement of fact, or set of them, to a factual conclusion which they do not formally entail. The inference may be to a general law, or by analogy to another particular instance.
     From: A.J. Ayer (The Problem of Knowledge [1956], 2.viii)
     A reaction: My preferred definition is 'learning from experience' - which I take to be the most rational behaviour you could possibly imagine. I don't think a definition should be couched in terms of 'objects' or 'particulars'.
2.viii p.74 We only discard a hypothesis after one failure if it appears likely to keep on failing
     Full Idea: Why should a hypothesis which has failed the test be discarded unless this shows it to be unreliable; that is, having failed once it is likely to fail again? There is no contradiction in a hypothesis that was falsified being more likely to pass in future.
     From: A.J. Ayer (The Problem of Knowledge [1956], 2.viii)
     A reaction: People may become more likely to pass a test after they have failed at the first attempt. Birds which fail to fly at the first attempt usually achieve total mastery of it. There are different types of hypothesis here.
1963 The Concept of a Person
§I p.84 We identify experiences by their owners, so we can't define owners by their experiences
     Full Idea: Normally we identify experiences in terms of the persons whose experiences they are; but this will lead to a vicious circle if persons themselves are to be analysed in terms of their experiences.
     From: A.J. Ayer (The Concept of a Person [1963], §I)
     A reaction: This (from a leading empiricist) is a nice basic challenge to all empiricist accounts of personal identity. One might respond my saying that the circle is not vicious. There are two interlinked concepts (experience and persons), like day and night.
§I p.87 Maybe induction could never prove the existence of something unobservable
     Full Idea: Some people hold that no inductive argument can give us any reason to believe in the existence of something which could not even in principle be observed.
     From: A.J. Ayer (The Concept of a Person [1963], §I)
     A reaction: I see nothing illogical in inferring the existence of a poltergeist from the recurrent flight of objects around my lounge. Only an excessive empiricism (which used to afflict Ayer) could lead to this claim.
§IV p.113 Consciousness must involve a subject, and only bodies identify subjects
     Full Idea: It may not make sense to talk of states of consciousness except as the experiences of some conscious subject; and it may well be that this conscious subject can not be identified except by reference to his body.
     From: A.J. Ayer (The Concept of a Person [1963], §IV)
     A reaction: It strikes me that Ayer deserves more credit as a pioneer of this view. It tracks back to what may turn out to be the key difficulty for Descartes - how do you individuate a mental substance? I may identify me, but how do I identify you?
§IV p.114 Memory is the best proposal as what unites bundles of experiences
     Full Idea: The most promising suggestion is that the bundles are tied together by means of memory.
     From: A.J. Ayer (The Concept of a Person [1963], §IV)
     A reaction: This is interesting for showing how Locke was essentially trying to meet (in advance) Hume's 'bundle' scepticism. Hume proposed associations as the unifying factor, instead of memories. Ayer proposes concepts as a candidate.
§IV p.114 Not all exerience can be remembered, as this would produce an infinite regress
     Full Idea: Not every experience can be remembered; otherwise each piece of remembering, which is itself an experience, would have to be remembered, and each remembering of a remembering and so ad infinitum.
     From: A.J. Ayer (The Concept of a Person [1963], §IV)
     A reaction: See Idea 5667. Ayer takes for granted two sorts of consciousness - current awareness, and memory. Ayer brings out a nice difficulty for Locke's proposal, but also draws attention to what may be a very basic misunderstanding about the mind.
§IV p.116 People own conscious states because they are causally related to the identifying body
     Full Idea: I think personal identity depends on the identity of the body, and that a person's ownership of states of consciousness consists in their standing in a special causal relation to the body by which he is identified.
     From: A.J. Ayer (The Concept of a Person [1963], §IV)
     A reaction: I think with this is right, with the slight reservation that Ayer talks as if there were two things which have a causal relationship, implying that the link is contingent. Better to think of the whole thing as a single causal network.
§IV p.128 Personal identity can't just be relations of experiences, because the body is needed to identify them
     Full Idea: A Humean theory, in which a person's identity is made to depend upon relations between experiences ..is not tenable unless the experiences themselves can be identified, and that is only possible through their association with the body.
     From: A.J. Ayer (The Concept of a Person [1963], §IV)
     A reaction: This seems to me a very fruitful response to difficulties with the 'bundle' view of a person - a better response than the a priori claims of Butler and Reid, or the transcendental argument of Kant. Only a philosopher could ignore the body.
1973 The Central Questions of Philosophy
§VI.A p.112 Self-consciousness is not basic, because experiences are not instrinsically marked with ownership
     Full Idea: Self-consciousness is not a primitive datum, or in other words the observer's experiences are not intrinsically marked as his own.
     From: A.J. Ayer (The Central Questions of Philosophy [1973], §VI.A)
     A reaction: This is a very Humean, ruthlessly empiricist view of the matter. Plenty of philosophers (existentialists, or Charles Taylor) would say that our experiences have our interests or values built into them. Why are they experiences, and not just events?
§VI.B p.116 Bodily identity and memory work together to establish personal identity
     Full Idea: In general the two criteria of memory and bodily identity work together.
     From: A.J. Ayer (The Central Questions of Philosophy [1973], §VI.B)
     A reaction: This seems better than any simplistic one-criterion approach. In life we use different criteria for our own identity, as when dreaming, or waking with a hangover, or wondering if we are dead after an accident.
§VI.B p.118 Qualia must be united by a subject, because they lead to concepts and judgements
     Full Idea: The ground for thinking that qualia are only experiences because they relate to a unifying subject is that they have to be identified, by being brought under concepts, and giving rise to judgements which usually go beyond them.
     From: A.J. Ayer (The Central Questions of Philosophy [1973], §VI.B)
     A reaction: Thus one of Hume's greatest fans gives the clearest objection to Hume. It strikes me as a very powerful objection, better than anything Carruthers offers (1394,1395,1396). The conceptual element is very hard to disentangle from the qualia.
§VI.B p.118 Is something an 'experience' because it relates to other experiences, or because it relates to a subject?
     Full Idea: Is the character of being an item of experience one that can accrue to a quale through its relation to other qualia, or must it consist in a relation to a subject, which is conscious of these elements and distinct from them?
     From: A.J. Ayer (The Central Questions of Philosophy [1973], §VI.B)
     A reaction: When nicely put like this, it is hard to see how qualia could be experiences just because they relate to one another. It begs the question of what is causing the relationship. There seems to be a Cogito-like assumption of a thinker.
§VI.C p.125 Temporal gaps in the consciousness of a spirit could not be bridged by memories
     Full Idea: If there were temporal gaps in the consciousness of disembodied spirits, the occurrences of memory-experiences would not be sufficient to bridge them.
     From: A.J. Ayer (The Central Questions of Philosophy [1973], §VI.C)
     A reaction: Ayer is very sympathetic to the idea that the body is a key ingredient in personal identity. Without a body, there would be no criteria at all for the continuity of a spirit which lost consciousness for a while, since consciousness is all it is.
§VI.D p.126 Originally I combined a mentalistic view of introspection with a behaviouristic view of other minds
     Full Idea: In 1936 I combined a mentalistic analysis of the propositions in which one attributes experiences to oneself with a behaviouristic analysis of the propositions in which one attributes experiences to others.
     From: A.J. Ayer (The Central Questions of Philosophy [1973], §VI.D)
     A reaction: He then criticises his view for inconsistency. Ryle preferred a behaviouristic account of introspection, but Ayer calls this 'ridiculous'. Ayer hunts for a compromise, but then settles for the right answer, which makes mentalism the 'best explanation'.
§VI.D p.130 Why shouldn't we say brain depends on mind? Better explanation!
     Full Idea: If mind and brain exactly correspond we have as good ground for saying the brain depends on the mind as the other way round; if predominance is given to the brain, the reason is that it fits into a wider explanatory system.
     From: A.J. Ayer (The Central Questions of Philosophy [1973], §VI.D)
     A reaction: A small but significant point. If an 'identity' theory is to be developed, then this step in the argument has to be justified. It is tempting here to move to the eliminativist view, because we no longer have to worry about a 'direction of priority'.
§VI.E p.132 Physicalism undercuts the other mind problem, by equating experience with 'public' brain events
     Full Idea: The acceptance of physicalism undercuts the other minds problem by equating experiences with events in the brain, which are publicly observable.
     From: A.J. Ayer (The Central Questions of Philosophy [1973], §VI.E)
     A reaction: It strikes me that if we could actually observe the operations of one another's brains, a great many of the problems of philosophy would never have appeared in the first place. Imagine a transparent skull and brain, with coloured waves moving through it.
§VI.E p.134 The theory of other minds has no rival
     Full Idea: The theory that other people besides oneself have mental states is one that has no serious rival.
     From: A.J. Ayer (The Central Questions of Philosophy [1973], §VI.E)
     A reaction: See 3463, where Searle says there is no such thing as our "theory" about other minds. In a science fiction situation (see 'Blade Runner'), this unrivalled theory could quickly unravel. It could even be a fact that you are the only humanoid with a mind.
§VI.E p.134 You can't infer that because you have a hidden birth-mark, everybody else does
     Full Idea: My knowing that I had a hidden birth-mark would not entitle me to infer with any great degree of confidence that the same was true of everybody else.
     From: A.J. Ayer (The Central Questions of Philosophy [1973], §VI.E)
     A reaction: This is the notorious 'induction from a single case' which was used by Mill to prove that other minds exist. It is a very nice illustration of the weakness of arguments from analogy. Probably analogy on its own is useless, but is a key part of induction.
9.A.5 p.197 We see properties necessary for a kind (in the definition), but not for an individual
     Full Idea: We can significantly ask what properties it is necessary for something to possess in order to be a thing of such and such a kind, since that asks what properties enter into the definition of the kind. But there is no such definition of the individual.
     From: A.J. Ayer (The Central Questions of Philosophy [1973], 9.A.5)
     A reaction: [Quoted, not surprisingly, by Wiggins] Illuminating. If essence is just about necessary properties, I begin to see why the sortal might be favoured. I take it to concern explanatory mechanisms, and hence the individual.
IX.C p.204 It is currently held that quantifying over something implies belief in its existence
     Full Idea: It is currently held that we are committed to a belief in the existence of anything over which we quantify.
     From: A.J. Ayer (The Central Questions of Philosophy [1973], IX.C)
IX.C p.208 Talk of propositions is just shorthand for talking about equivalent sentences
     Full Idea: Our talk of propositions should not be regarded as anything more than a concise way of talking about equivalent sentences.
     From: A.J. Ayer (The Central Questions of Philosophy [1973], IX.C)
     A reaction: Wrong, though I can see why he says it. We struggle to express difficult propositions by offering several similar (but not equivalent) sentences. What is the criterion for deciding his 'equivalence'?