Ideas from 'Language,Truth and Logic' by A.J. Ayer [1936], by Theme Structure

[found in 'Language, Truth and Logic' by Ayer,A.J. [Penguin 1974,0-14-021200-0]].

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1. Philosophy / D. Nature of Philosophy / 3. Philosophy Defined
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).
1. Philosophy / D. Nature of Philosophy / 5. Aims of Philosophy / e. Philosophy as reason
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.
1. Philosophy / E. Nature of Metaphysics / 7. Against Metaphysics
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.
1. Philosophy / F. Analytic Philosophy / 7. Limitations of Analysis
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.
1. Philosophy / G. Scientific Philosophy / 3. Scientism
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.
3. Truth / H. Deflationary Truth / 2. Deflationary Truth
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".
6. Mathematics / C. Sources of Mathematics / 6. Logicism / a. Early logicism
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).
7. Existence / D. Theories of Reality / 1. Ontologies
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.
11. Knowledge Aims / B. Certain Knowledge / 1. Certainty
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.
11. Knowledge Aims / C. Knowing Reality / 2. Phenomenalism
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'.
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.
12. Knowledge Sources / A. A Priori Knowledge / 4. A Priori as Necessities
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.
12. Knowledge Sources / A. A Priori Knowledge / 5. A Priori Synthetic
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?
12. Knowledge Sources / A. A Priori Knowledge / 7. A Priori from Convention
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.
12. Knowledge Sources / A. A Priori Knowledge / 8. A Priori as Analytic
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.
12. Knowledge Sources / B. Perception / 4. Sense Data / a. Sense-data theory
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.
12. Knowledge Sources / B. Perception / 7. Causal Perception
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.
12. Knowledge Sources / C. Rationalism / 1. Rationalism
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.
12. Knowledge Sources / D. Empiricism / 1. Empiricism
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.
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.
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.
12. Knowledge Sources / D. Empiricism / 4. Pro-Empiricism
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'?
12. Knowledge Sources / D. Empiricism / 5. Empiricism Critique
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.
14. Science / C. Induction / 2. Aims of Induction
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.
14. Science / C. Induction / 3. Limits of Induction
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.
15. Nature of Minds / A. Nature of Mind / 4. Other Minds / b. Scepticism of other minds
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'.
15. Nature of Minds / A. Nature of Mind / 4. Other Minds / c. Knowing other minds
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.
16. Persons / B. Nature of the Self / 5. Self as Associations
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'?
16. Persons / B. Nature of the Self / 7. Self and Body / a. Self needs body
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.
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.
17. Mind and Body / A. Mind-Body Dualism / 8. Dualism of Mind Critique
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.
19. Language / A. Nature of Meaning / 5. Meaning as Verification
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.
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.
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.
22. Metaethics / A. Ethics Foundations / 2. Source of Ethics / c. Ethical intuitionism
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).
22. Metaethics / A. Ethics Foundations / 2. Source of Ethics / h. Expressivism
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.
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.
28. God / A. Divine Nature / 4. Divine Contradictions
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.
28. God / B. Proving God / 2. Proofs of Reason / b. Ontological Proof critique
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".
28. God / C. Attitudes to God / 5. Atheism
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.
29. Religion / D. Religious Issues / 1. Religious Commitment / c. Religious Verification
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.