16 ideas
5331 | You can't infer that because you have a hidden birth-mark, everybody else does [Ayer] |
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. |
14238 | A class is an aggregate of objects; if you destroy them, you destroy the class; there is no empty class [Frege] |
Full Idea: A class consists of objects; it is an aggregate, a collective unity, of them; if so, it must vanish when these objects vanish. If we burn down all the trees of a wood, we thereby burn down the wood. Thus there can be no empty class. | |
From: Gottlob Frege (Elucidation of some points in E.Schröder [1895], p.212), quoted by Oliver,A/Smiley,T - What are Sets and What are they For? | |
A reaction: This rests on Cantor's view of a set as a collection, rather than on Dedekind, which allows null and singleton sets. |
2611 | It is currently held that quantifying over something implies belief in its existence [Ayer] |
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) | |
A reaction: In a fairy tale we quantify over fairies, so some further criterion will obviously be needed. |
16520 | We see properties necessary for a kind (in the definition), but not for an individual [Ayer] |
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. |
8840 | There are five possible responses to the problem of infinite regress in justification [Cleve] |
Full Idea: Sceptics respond to the regress problem by denying knowledge; Foundationalists accept justifications without reasons; Positists say reasons terminate is mere posits; Coherentists say mutual support is justification; Infinitists accept the regress. | |
From: James Van Cleve (Why coherence is not enough [2005], I) | |
A reaction: A nice map of the territory. The doubts of Scepticism are not strong enough for anyone to embrace the view; Foundationalist destroy knowledge (?), as do Positists; Infinitism is a version of Coherentism - which is the winner. |
8841 | Modern foundationalists say basic beliefs are fallible, and coherence is relevant [Cleve] |
Full Idea: Contemporary foundationalists are seldom of the strong Cartesian variety: they do not insist that basic beliefs be absolutely certain. They also tend to allow that coherence can enhance justification. | |
From: James Van Cleve (Why coherence is not enough [2005], III) | |
A reaction: It strikes me that they have got onto a slippery slope. How certain are the basic beliefs? How do you evaluate their certainty? Could incoherence in their implications undermine them? Skyscrapers need perfect foundations. |
2613 | The theory of other minds has no rival [Ayer] |
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. |
5328 | Originally I combined a mentalistic view of introspection with a behaviouristic view of other minds [Ayer] |
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'. |
5330 | Physicalism undercuts the other mind problem, by equating experience with 'public' brain events [Ayer] |
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. |
5325 | Is something an 'experience' because it relates to other experiences, or because it relates to a subject? [Ayer] |
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. |
5326 | Qualia must be united by a subject, because they lead to concepts and judgements [Ayer] |
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. |
5324 | Bodily identity and memory work together to establish personal identity [Ayer] |
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. |
5322 | Self-consciousness is not basic, because experiences are not instrinsically marked with ownership [Ayer] |
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? |
5327 | Temporal gaps in the consciousness of a spirit could not be bridged by memories [Ayer] |
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. |
5329 | Why shouldn't we say brain depends on mind? Better explanation! [Ayer] |
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'. |
2610 | Talk of propositions is just shorthand for talking about equivalent sentences [Ayer] |
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'? |