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All the ideas for 'fragments/reports', 'Language,Truth and Logic' and 'Potentiality'

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77 ideas

1. Philosophy / D. Nature of Philosophy / 3. Philosophy Defined
Philosophy is a department of logic [Ayer]
     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 [Ayer]
     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 [Ayer, by Macdonald,C]
     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 [Ayer]
     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 [Ayer]
     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.
2. Reason / E. Argument / 1. Argument
Slippery slope arguments are challenges to show where a non-arbitrary boundary lies [Vetter]
     Full Idea: Slippery slope arguments are not intended as demonstrative arguments, but rather as a challenge to show where a boundary is, and to show that the boundary is not arbitrary.
     From: Barbara Vetter (Potentiality [2015], 5.3.3)
     A reaction: [extracted from details of its context] You could respond by saying that a slippery slope levels off, rather than hitting a wall or plunging to perdition.
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 [Ayer]
     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".
4. Formal Logic / D. Modal Logic ML / 3. Modal Logic Systems / c. System D
Deontic modalities are 'ought-to-be', for sentences, and 'ought-to-do' for predicates [Vetter]
     Full Idea: Deontic modality can be divided into sentence-modifying 'ought-to-be' modals, and predicate-modifying 'ought-to-do' modals.
     From: Barbara Vetter (Potentiality [2015], 6.9.2)
     A reaction: [She cites Brennan 1993] These two seem to correspond to what is 'good' (ought to be), and what is 'right' (ought to do). Since I like that distinction, I also like this one.
4. Formal Logic / D. Modal Logic ML / 3. Modal Logic Systems / h. System S5
S5 is undesirable, as it prevents necessities from having contingent grounds [Vetter]
     Full Idea: Wedgwood (2007:220) argues that S5 is undesirable because it excludes that necessary truths may have contingent grounds.
     From: Barbara Vetter (Potentiality [2015], 6.4 n5)
     A reaction: Cameron defends the possibility of necessity grounded in contingency, against Blackburn's denial of it. It's interesting that we choose the logic on the basis of the metaphysics. Shouldn't there be internal reasons for a logic's correctness?
4. Formal Logic / D. Modal Logic ML / 7. Barcan Formula
The Barcan formula endorses either merely possible things, or makes the unactualised impossible [Vetter]
     Full Idea: Subscribers to the Barcan formula must either be committed to the existence of mere possibilia (such as possible unicorns), or deny many unactualised possibilities of existence.
     From: Barbara Vetter (Potentiality [2015], 7.5)
     A reaction: It increasingly strikes me that the implications of the Barcan formula are ridiculous. Williamson is its champion, but I'm blowed if I can see why. What could a possible unicorn be like? Without them, must we say unicorns are impossible?
6. Mathematics / C. Sources of Mathematics / 6. Logicism / a. Early logicism
Maths and logic are true universally because they are analytic or tautological [Ayer]
     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 / A. Nature of Existence / 1. Nature of Existence
The world is either a whole made of its parts, or a container which contains its parts [Vetter]
     Full Idea: We can think of the world as a 'whole' that has everything as its parts, like raisins in a cake, or we can think of the world as a 'container', which is disjoint from everything there is, like a bottle containing water.
     From: Barbara Vetter (Potentiality [2015], 7.3)
     A reaction: [compressed] Space and time seem to have a special role here, and it is hard to think of any other candidates for being the 'container'. I think I will apply my 'what's it made of' test to ontology, and opt for the world as a 'whole'.
7. Existence / C. Structure of Existence / 1. Grounding / b. Relata of grounding
Grounding can be between objects ('relational'), or between sentences ('operational') [Vetter]
     Full Idea: 'Relational' grounding is between entities, best expressed by the two-place predicate 'x grounds y'. 'Operational' grounding is between sentences, best expressed by the two-place sentence operator read as 'because of' or 'in virtue of'.
     From: Barbara Vetter (Potentiality [2015], 1.6)
7. Existence / C. Structure of Existence / 5. Supervenience / d. Humean supervenience
The Humean supervenience base entirely excludes modality [Vetter]
     Full Idea: Humean supervenience excludes modality - the whole modal package - from the supervenience base. The Humean world is, at root, thoroughly non-modal.
     From: Barbara Vetter (Potentiality [2015], 1.2)
     A reaction: This sums up my problem with David Lewis with perfect clarity. He is just excessively empirical. Hume himself also excluded modality from the basic impressions. Locke allows powerful essences (even if they are well hidden).
7. Existence / D. Theories of Reality / 1. Ontologies
Positivists regard ontology as either meaningless or stipulated [Ayer, by Robinson,H]
     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.
8. Modes of Existence / B. Properties / 3. Types of Properties
A determinate property must be a unique instance of the determinable class [Vetter]
     Full Idea: The crucial feature of the determinates / determinables relation is that to possess the determinable property, an object must possess exactly one of the determinate properties.
     From: Barbara Vetter (Potentiality [2015], 5.7.2)
     A reaction: This sounds like a determinable being a function, and the determinate being its output. If 'scarlet' is a determinate of the determinables 'red' or 'coloured', it is not obvious that there is only one possible shade of scarlet. This schema oversimplifies.
8. Modes of Existence / C. Powers and Dispositions / 6. Dispositions / a. Dispositions
I have an 'iterated ability' to learn the violin - that is, the ability to acquire that ability [Vetter]
     Full Idea: I do not have the ability to play the violin. Nor does my desk. Unlike my desk, however, I possess the ability to learn to play the violin - the ability, that is, to acquire the ability to play the violin. I have an 'iterated ability' to play the violin.
     From: Barbara Vetter (Potentiality [2015], 4.6)
     A reaction: An important idea, though the examples are more likely to come from human behaviour than from the non-human physical world.
8. Modes of Existence / C. Powers and Dispositions / 6. Dispositions / c. Dispositions as conditional
We should think of dispositions as 'to do' something, not as 'to do something, if ....' [Vetter]
     Full Idea: We should think in terms of dispositions in terms of the manifestation alone - not as a disposition to ...if..., but as a disposition to ..., full stop.
     From: Barbara Vetter (Potentiality [2015], 1.7)
     A reaction: This way of individuating dispositions seems plausible. Some dispositions only have one trigger, but others have many. All sorts of things are inclined to trigger a human smile, but we are just disposed to smile. Some people smile at disasters.
8. Modes of Existence / C. Powers and Dispositions / 6. Dispositions / d. Dispositions as occurrent
Nomological dispositions (unlike ordinary ones) have to be continually realised [Vetter]
     Full Idea: Nomological dispositions such as electric charge seem different from ordinary dispositions. A particle's being electrically charged is not just a possibility of exerting a certain force. Rather, the particle has to exert a force in certain circumstances.
     From: Barbara Vetter (Potentiality [2015], 2.7)
     A reaction: I can only pull when there is something to pull, but a magnet seems to have a 'field' of attraction which is pullish in character. Does it detect something to pull (like a monad)? Can there be a force which has no object?
8. Modes of Existence / C. Powers and Dispositions / 7. Against Powers
How can spatiotemporal relations be understood in dispositional terms? [Vetter]
     Full Idea: Spatiotemporal relations are a prime example of properties that are difficult to understand in dispositional terms.
     From: Barbara Vetter (Potentiality [2015], 1.6)
     A reaction: [Vetter refers to A.Bird 2007 Ch.8 for an attempt] One approach would be to question whether they are 'properties'. I don't think of relations as properties, even if they are predicates. Is space a property of something?
9. Objects / E. Objects over Time / 12. Origin as Essential
Why does origin matter more than development; why are some features of origin more important? [Vetter]
     Full Idea: Not every feature of an individual's origin is plausibly considered necessary, so we can distinguish two questions: 'why origin, rather than development?', and 'why these particular features of origin?'.
     From: Barbara Vetter (Potentiality [2015], 6.2)
     A reaction: [she cites P. Mackie 1998] The point is that exactly where someone was born doesn't seem vital. If it is nothing more than that every contingent object must have an origin, that is not very exciting.
We take origin to be necessary because we see possibilities as branches from actuality [Vetter]
     Full Idea: The plausibility of the necessity of origin is a symptom of our general tendency to think of possibility in terms of the 'branching model' - that unactualised possibilities must branch off from actuality, at some point.
     From: Barbara Vetter (Potentiality [2015], 7.9)
     A reaction: [she cites P. Mackie 1998] It is hard to see how we could flatly deny some possibilities which had absolutely no connection with actuality, and were probably quite unimaginable for us.
10. Modality / A. Necessity / 2. Nature of Necessity
The modern revival of necessity and possibility treated them as special cases of quantification [Vetter]
     Full Idea: Necessity and possibility had a revival with the development of modal logic, treating them as special cases of the existential and universal quantifiers, ranging over an infinity of possible worlds.
     From: Barbara Vetter (Potentiality [2015], 1.1)
     A reaction: The problem seems to be that possible worlds offer a very useful and interesting 'model' of modality, but say nothing at all about its nature. Any more than a weather map will show you what weather is.
It is necessary that p means that nothing has the potentiality for not-p [Vetter]
     Full Idea: Necessities mark the limits of the potentialities that objects have. More precisely, it is necessary that p just in case nothing has, or had, or will have a potentiality to be such that not-p.
     From: Barbara Vetter (Potentiality [2015], 6.2)
     A reaction: [See Vetter's other ideas for her potentiality account of modality] If we wish to build a naturalistic account of modality (and if you don't want that then your untethered metaphysics will drift away in logical space) then this is the way to go.
10. Modality / B. Possibility / 1. Possibility
Possibilities are potentialities of actual things, but abstracted from their location [Vetter]
     Full Idea: When we speak of possibility, we speak of potentiality in abstraction from its possessor; a possibility is a potentiality somewhere or other in the world, no matter where.
     From: Barbara Vetter (Potentiality [2015], 6.1)
     A reaction: I note that, as so often, this is psychological abstraction, which is usually sneered at by modern philosophers (e.g. Geach), and yet is employed all the time. This is Vetter's key thesis, which I like.
All possibility is anchored in the potentiality of individual objects [Vetter]
     Full Idea: Potentiality is, metaphorically speaking, possibility anchored in individual objects; I claim that all possibility is thus anchored in some individual object(s) or other.
     From: Barbara Vetter (Potentiality [2015], 1.1)
     A reaction: This will be fine for specific physical possibilities, but may become tricky for possibilities that are increasingly abstract, or universal, or idealised. I agree with the general approach. Anchor modality in reality (which is physical!).
Possibility is a generalised abstraction from the potentiality of its bearer [Vetter]
     Full Idea: We should think of possibility as potentiality in abstraction from its bearer. So 'it is possible that p' is defined as 'something has an iterated potentiality for it to be the case that p'.
     From: Barbara Vetter (Potentiality [2015], 1.4)
     A reaction: If possibilities are abstractions from potentialities, I am inclined the treat potentialities as abstractions from dispositions, and dispositions (and properties) as abstractions from powers. Powers are not abstractions - they are the reality.
10. Modality / B. Possibility / 4. Potentiality
Potentiality is the common genus of dispositions, abilities, and similar properties [Vetter]
     Full Idea: Potentiality can now be recognised as the common genus of dispositions and such related properties as abilities.
     From: Barbara Vetter (Potentiality [2015], 4.1)
     A reaction: This is the reason why Vetter defends a metaphysics of modality based on potentialities, rather than on narrower concepts such as dispositions, powers or essences. She can evade the problems which those narrower concepts raise.
Water has a potentiality to acquire a potentiality to break (by freezing) [Vetter]
     Full Idea: Water has no potentiality to break. But water has a potentiality to be frozen and turn into ice, which does have a potentiality to break. So water has a potentiality to acquire a potentiality to break.
     From: Barbara Vetter (Potentiality [2015], 4.6)
     A reaction: Thus potentially has an 'iterated' character to it, and an appropriate modal logic for it will have to allow for those iterations. She suggests a version of System T modal logic.
A potentiality may not be a disposition, but dispositions are strong potentialities [Vetter, by Friend/Kimpton-Nye]
     Full Idea: Although not all potentialities are dispositions, Vetter claims that all dispositions are potentialities which are had to a sufficiently high degree.
     From: report of Barbara Vetter (Potentiality [2015]) by Friend/Kimpton-Nye - Dispositions and Powers 2.4.2
     A reaction: This sounds plausible. A potentiality could be faint or negligible, but once it is a serious possibility it becomes a 'disposition'. ...I suppose. But if the meteor is probably going to hit my house, it doesn't mean it has a disposition to do so.
Potentiality does the explaining in metaphysics; we don't explain it away or reduce it [Vetter]
     Full Idea: This book is a plea for recognising potentiality as an explanans in the metaphysics of modality, rather than as something in need of explanation or reduction.
     From: Barbara Vetter (Potentiality [2015], 1.1)
     A reaction: Something has to do the explaining, and it is obviously much better to have some aspect of the real world do the job, rather than remote abstractions such as laws, possible worlds or Forms. Personally I like the potentiality of 'powers'.
Potentiality logic is modal system T. Stronger systems collapse iterations, and necessitate potentials [Vetter]
     Full Idea: The logic for potentiality corresponds to modal system T, the minimum for metaphysics. The S4 axiom ◊◊φ → ◊φ says iterated potentialities collapse, and the S5 ◊φ → □◊φ says potentialities can't be lost.
     From: Barbara Vetter (Potentiality [2015], 5.9)
     A reaction: [compressed] This seems persuasive. I nice example of modern analytic metaphysics, that you have to find a logic that suits your theory. N.Salmon defends system T for all of metaphysics, though most people favour S5.
There are potentialities 'to ...', but possibilities are 'that ....'. [Vetter]
     Full Idea: Potentialities are 'potentialities to ....', while possibilities are 'possibilities that ....'.
     From: Barbara Vetter (Potentiality [2015], 6.4)
     A reaction: This feels a bit like a stipulation, rather than a precise description of normal usage. That said, it is quite a nice distinction. It sounds as if an event follows a potentiality, and a state of affairs follows a possibility. Active and passive?
Potentialities may be too weak to count as 'dispositions' [Vetter]
     Full Idea: Potentialities may get exercised despite having a degree that is too low for them to qualify as dispositions.
     From: Barbara Vetter (Potentiality [2015], 5.7.4)
     A reaction: The key reason why her book is called 'Potentialities', rather than 'Dispositions'. She still wants to offer a naturalistic picture which ties potentialities to individual objects, but I am wondering whether potentialities are too abstract for the job.
10. Modality / E. Possible worlds / 2. Nature of Possible Worlds / c. Worlds as propositions
If worlds are sets of propositions, how do we know which propositions are genuinely possible? [Vetter]
     Full Idea: If possible worlds are sets of propositions, we need some way to distinguish those sets of propositions that do from those that do not correspond to genuine possibilities.
     From: Barbara Vetter (Potentiality [2015], 1.2)
     A reaction: The idea of a 'genuine' possibility does not seem to play a role in the conceptual scheme of those who treat possibility entirely in terms of possible worlds. If possibility is primitive, or is a set of worlds, there can be no criterion for 'genuine'.
10. Modality / E. Possible worlds / 3. Transworld Objects / e. Possible Objects
Are there possible objects which nothing has ever had the potentiality to produce? [Vetter]
     Full Idea: Is it not possible that there be objects with (natural) properties that no actual thing ever had the potentiality to have, to produce, or constitute? (Call such properties 'super-alien properties').
     From: Barbara Vetter (Potentiality [2015], 7.5)
     A reaction: This is a problem for her potentiality account of possibility. Her solution is (roughly) to either deny the super-aliens, or have chains of iterated possibility which take this case back to actuality. That sounds OK to me.
11. Knowledge Aims / B. Certain Knowledge / 1. Certainty
Only tautologies can be certain; other propositions can only be probable [Ayer]
     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' [Robinson,H on Ayer]
     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 [Ayer]
     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 [Ierubino on Ayer]
     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 [Ayer]
     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 [Ayer]
     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 [Ayer]
     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 [Ayer, by Robinson,H]
     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 [Ayer]
     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 [Ayer]
     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 [O'Grady on Ayer]
     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 [Ayer]
     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 [Ayer]
     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 [Ayer]
     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 [Ayer]
     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 [Ayer]
     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 [Ayer]
     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.
14. Science / D. Explanation / 2. Types of Explanation / a. Types of explanation
Explanations by disposition are more stable and reliable than those be external circumstances [Vetter]
     Full Idea: Patterns of behaviour may be explained by circumstances external to the individual, but dispositional explanations, based on the instrinsic make-up of individuals are typically more reliable and stable.
     From: Barbara Vetter (Potentiality [2015], 3.5)
     A reaction: [compressed] This is very nice support for the view I have been defending. She doesn't deal in essences, and prefers 'potentialities' (as broader) to 'dispositions'. The point is to explain events by the natures of the ingredients.
Grounding is a kind of explanation, suited to metaphysics [Vetter]
     Full Idea: Grounding is a kind of explanation - and specifically, the kind of metaphysical explanation that metaphysicians are after.
     From: Barbara Vetter (Potentiality [2015], 4.5)
     A reaction: Depending on how you interpret 'grounding', it is plausible that it is the sort of explanation that physicists and economists are after as well. If the aim is to understand the structure of everything, the target is to know what grounds what.
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 [Ayer]
     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 [Ayer]
     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 [Ayer]
     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 [Ayer]
     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 [Ayer]
     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' [Ayer]
     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 [Ayer]
     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 [Ayer]
     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 [Ayer]
     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 [Ayer]
     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 [Ayer, by Smith,M]
     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 [Ayer]
     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.
23. Ethics / C. Virtue Theory / 2. Elements of Virtue Theory / e. Character
Virtue comes more from habit than character [Critias]
     Full Idea: More men are good through habit than through character.
     From: Critias (fragments/reports [c.440 BCE], B09), quoted by John Stobaeus - Anthology 3.29.41
26. Natural Theory / D. Laws of Nature / 5. Laws from Universals
The view that laws are grounded in substance plus external necessity doesn't suit dispositionalism [Vetter]
     Full Idea: The Armstrong/Tooley/Dretske view, which takes laws to be substantial but grounded in a relation of nomic necessitation external to the properties themselves, is not an attractive option for the dispositionalist.
     From: Barbara Vetter (Potentiality [2015], 7.8)
     A reaction: The point is that the dispositionalist sees laws as grounded in the properties. I prefer her other option, of dispositionalism plus a 'shallow' view of laws (which she attributes to Mumford). The laws are as Lewis says, but powers explain them.
26. Natural Theory / D. Laws of Nature / 8. Scientific Essentialism / b. Scientific necessity
Dispositional essentialism allows laws to be different, but only if the supporting properties differ [Vetter]
     Full Idea: Even on the dispositional essentialist view the world might have been governed by different laws, if those laws involved different properties. What is excluded is the possibility of different laws involving the same properties as our actual laws.
     From: Barbara Vetter (Potentiality [2015], 7.8)
     A reaction: Important. Critics of dispositional essentialism accuse it of promoting the idea that the laws of nature are necessary, a claim for which we obviously have no evidence. I prefer to say they are necessary given that 'stuff', rather than those properties.
27. Natural Reality / D. Time / 1. Nature of Time / f. Eternalism
If time is symmetrical between past and future, why do they look so different? [Vetter]
     Full Idea: Any defender of the symmetry of time will have to provide some explanation of the obstinate appearance that the future is very different from the past.
     From: Barbara Vetter (Potentiality [2015], 5.8)
     A reaction: Presumably you have to say that it is all there, but only one end of the time spectrum is revealed to us, namely the past. But how do we get this uniquely lopsided view? Being an ominiscient god is more obvious than being a lopsided human.
27. Natural Reality / D. Time / 1. Nature of Time / h. Presentism
Presentists explain cross-temporal relations using surrogate descriptions [Vetter]
     Full Idea: Presentists usually deal with the lack of cross-temporal relations by the construction of a surrogate, by way of paraphrasing the objectionable relation ascriptions. 'I admire Socrates' becomes 'I admire the Socrates properties'.
     From: Barbara Vetter (Potentiality [2015], 7.9)
     A reaction: [compressed. The cites Markosian 2004:63] Why can't I just say 'I admire Socrates, who no longer exists'? The present includes tensed facts, and memories and evidence-based theories. Admiring is not a direct relation between objects.
28. God / A. Divine Nature / 4. Divine Contradictions
A person with non-empirical attributes is unintelligible. [Ayer]
     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 [Ayer]
     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
Fear of the gods was invented to discourage secret sin [Critias]
     Full Idea: When the laws forbade men to commit open crimes of violence, and they began to do them in secret, a wise and clever man invented fear of the gods for mortals, to frighten the wicked, even if they sin in secret.
     From: Critias (fragments/reports [c.440 BCE], B25), quoted by Sextus Empiricus - Against the Professors (six books) 9.54
If theism is non-sensical, then so is atheism. [Ayer]
     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 [Ayer]
     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.