24 ideas
| 3993 | Arguments are nearly always open to challenge, but they help to explain a position rather than force people to believe [Lewis] |
| Full Idea: Philosophical arguments are never incontrovertible - well, hardly ever. Their purpose is to help expound a position, not to coerce agreement. | |
| From: David Lewis (Lewis: reduction of mind (on himself) [1994], p.419) | |
| A reaction: A bit over-cautious, perhaps. Most philosophers are converted to a position when they hear a single key argument, though it is probably 'tipping the balance' of previous discussions. |
| 21695 | The set scheme discredited by paradoxes is actually the most natural one [Quine] |
| Full Idea: Each proposed revision of set theory is unnatural, because the natural scheme is the unrestricted one that the antinomies discredit. | |
| From: Willard Quine (The Ways of Paradox [1961], p.16) | |
| A reaction: You can either takes this free-far-all version of set theory, and gradually restrain it for each specific problem, or start from scratch and build up in safe steps. The latter is (I think) the 'iterated' approach. |
| 21693 | Russell's antinomy challenged the idea that any condition can produce a set [Quine] |
| Full Idea: In the case of Russell's antinomy, the tacit and trusted pattern of reasoning that is found wanting is this: for any condition you can formulate, there is a class whose members are the things meeting the condition. | |
| From: Willard Quine (The Ways of Paradox [1961], p.11) | |
| A reaction: This is why Russell's Paradox is so important for set theory, which in turn makes it important for the foundations of mathematics. |
| 21691 | Antinomies contradict accepted ways of reasoning, and demand revisions [Quine] |
| Full Idea: An 'antinomy' produces a self-contradiction by accepted ways of reasoning. It establishes that some tacit and trusted pattern of reasoning must be made explicit and henceforward be avoided or revised. | |
| From: Willard Quine (The Ways of Paradox [1961], p.05) | |
| A reaction: Quine treats antinomies as of much greater importance than mere paradoxes. It is often possible to give simple explanations of paradoxes, but antinomies go to the root of our belief system. This was presumably Kant's intended meaning. |
| 21690 | Whenever the pursuer reaches the spot where the pursuer has been, the pursued has moved on [Quine] |
| Full Idea: The Achilles argument is that (if the front runner keeps running) each time the pursuer reaches a spot where the pursuer has been, the pursued has moved a bit beyond. | |
| From: Willard Quine (The Ways of Paradox [1961], p.03) | |
| A reaction: Quine is always wonderfully lucid, and this is the clearest simple statement of the paradox. |
| 21689 | A barber shaves only those who do not shave themselves. So does he shave himself? [Quine] |
| Full Idea: In a certain village there is a barber, who shaves all and only those men in the village who do not shave themselves. So does the barber shave himself? The barber shaves himself if and only if he does not shave himself. | |
| From: Willard Quine (The Ways of Paradox [1961], p.02) | |
| A reaction: [Russell himself quoted this version of his paradox, from an unnamed source] Quine treats his as trivial because it only concerns barbers, but the full Russell paradox is a major 'antinomy', because it concerns sets. |
| 21694 | Membership conditions which involve membership and non-membership are paradoxical [Quine] |
| Full Idea: With Russell's antinomy, ...each tie the trouble comes of taking a membership condition that itself talks in turn of membership and non-membership. | |
| From: Willard Quine (The Ways of Paradox [1961], p.13) | |
| A reaction: Hence various stipulations to rule out vicious circles or referring to sets of the 'wrong type' are invoked to cure the problem. The big question is how strong to make the restrictions. |
| 21692 | If we write it as '"this sentence is false" is false', there is no paradox [Quine] |
| Full Idea: If we supplant the sentence 'this sentence is false' with one saying what it refers to, we get '"this sentence is false" is false'. But then the whole outside sentence attributes falsity no longer to itself but to something else, so there is no paradox. | |
| From: Willard Quine (The Ways of Paradox [1961], p.07) | |
| A reaction: Quine is pointing us towards type theory and meta-languages to solve the problem. We now have the Revenge Liar, and the problem has not been fully settled. |
| 3990 | The whole truth supervenes on the physical truth [Lewis] |
| Full Idea: The whole truth supervenes on the physical truth. | |
| From: David Lewis (Lewis: reduction of mind (on himself) [1994], p.412) | |
| A reaction: This seems to me the central truth about brains, and we should not be lured into abandoning it. We should not, however, exclude the possibility that there is a non-physical reality. |
| 3991 | Where pixels make up a picture, supervenience is reduction [Lewis] |
| Full Idea: In the case of millions of pixels making up a picture on a computer screen, the supervenience is reduction. | |
| From: David Lewis (Lewis: reduction of mind (on himself) [1994], p.414) | |
| A reaction: Since 'supervenience' seems a suspect relationship about which no one is clear, this is a point very much worth making. |
| 3995 | A mind is an organ of representation [Lewis] |
| Full Idea: A mind is an organ of representation. | |
| From: David Lewis (Lewis: reduction of mind (on himself) [1994], p.421) | |
| A reaction: This does not seem to necessarily involve awareness, so it seems to put intentionality at the centre of things. It is a good slogan. |
| 7658 | Obviously there can't be a functional anaylsis of qualia if they are defined by intrinsic properties [Dennett] |
| Full Idea: If you define qualia as intrinsic properties of experiences considered in isolation from all their causes and effects, logically independent of all dispositional properties, then they are logically guaranteed to elude all broad functional analysis. | |
| From: Daniel C. Dennett (Sweet Dreams [2005], Ch.8) | |
| A reaction: This is a good point - it seems daft to reify qualia and imagine them dangling in mid-air with all their vibrant qualities - but that is a long way from saying there is nothing more to qualia than functional roles. Functions must be exlained too. |
| 7655 | The work done by the 'homunculus in the theatre' must be spread amongst non-conscious agencies [Dennett] |
| Full Idea: All the work done by the imagined homunculus in the Cartesian Theater must be distributed among various lesser agencies in the brain, none of which is conscious. | |
| From: Daniel C. Dennett (Sweet Dreams [2005], Ch.3) | |
| A reaction: Dennett's account crucially depends on consciousness being much more fragmentary than most philosophers claim it to be. It is actually full of joints, which can come apart. He may be right. |
| 3994 | Human pain might be one thing; Martian pain might be something else [Lewis] |
| Full Idea: Human pain might be one thing. Martian pain might be something else. | |
| From: David Lewis (Lewis: reduction of mind (on himself) [1994], p.420) | |
| A reaction: A key suggestion in support of type-type physicalism, and against the multiple realisability objection to the identity theory |
| 3989 | I am a reductionist about mind because I am an a priori reductionist about everything [Lewis] |
| Full Idea: My reductionism about mind began as part of an a priori reductionism about everything. | |
| From: David Lewis (Lewis: reduction of mind (on himself) [1994], p.412) | |
| A reaction: He says this is 'a priori' to avoid giving hostages to fortune, but I think is the best explanation of the total evidence facing us |
| 7657 | Intelligent agents are composed of nested homunculi, of decreasing intelligence, ending in machines [Dennett] |
| Full Idea: As long as your homunculi are more stupid and ignorant than the intelligent agent they compose, the nesting of homunculi within homunculi can be finite, bottoming out, eventually, with agents so unimpressive they can be replaced by machines. | |
| From: Daniel C. Dennett (Sweet Dreams [2005], Ch.6) | |
| A reaction: [Dennett first proposed this in 'Brainstorms' 1978]. This view was developed well by Lycan. I rate it as one of the most illuminating ideas in the modern philosophy of mind. All complex systems (like aeroplanes) have this structure. |
| 7656 | I don't deny consciousness; it just isn't what people think it is [Dennett] |
| Full Idea: I don't maintain, of course, that human consciousness does not exist; I maintain that it is not what people often think it is. | |
| From: Daniel C. Dennett (Sweet Dreams [2005], Ch.3) | |
| A reaction: I consider Dennett to be as near as you can get to an eliminativist, but he is not stupid. As far as I can see, the modern philosopher's bogey-man, the true total eliminativist, simply doesn't exist. Eliminativists usually deny propositional attitudes. |
| 3992 | Folk psychology makes good predictions, by associating mental states with causal roles [Lewis] |
| Full Idea: Folk psychology is a powerful instrument of prediction, …which associates with each mental state a typical causal role. | |
| From: David Lewis (Lewis: reduction of mind (on himself) [1994], p.416) | |
| A reaction: This seems a good account of why we should take folk psychology very seriously, even if it is sometimes wrong (e.g. about people who are mentally ill). |
| 3996 | Folk psychology doesn't say that there is a language of thought [Lewis] |
| Full Idea: I don't believe that folk psychology says there is a language of thought. | |
| From: David Lewis (Lewis: reduction of mind (on himself) [1994], p.422) | |
| A reaction: This is aimed at Jerry Fodor. Certainly folk psychology is a strong theory, but a so-called 'language of thought' (the brain's machine code) seems a much weaker one. |
| 7654 | What matters about neuro-science is the discovery of the functional role of the chemistry [Dennett] |
| Full Idea: Neuro-science matters because - and only because - we have discovered that the many different neuromodulators and other chemical messengers that diffuse throughout the brain have functional roles that make important differences. | |
| From: Daniel C. Dennett (Sweet Dreams [2005], Ch.1) | |
| A reaction: I agree with Dennett that this is the true ground for pessimism about spectacular breakthroughs in artificial intelligence, rather than abstract concerns about irreducible features of the mind like 'qualia' and 'rationality'. |
| 3998 | If you don't share an external world with a brain-in-a-vat, then externalism says you don't share any beliefs [Lewis] |
| Full Idea: If the famous brain in a bottle is your exact duplicate in brain states, but only experiences the computer's virtual reality, so that you share no objects of acquaintance, then according to externalists you share no beliefs whatsoever. | |
| From: David Lewis (Lewis: reduction of mind (on himself) [1994], p.424) | |
| A reaction: A very nice reductio ad absurdum of the idea that all concepts and beliefs have external meaning. |
| 3997 | Nothing shows that all content is 'wide', or that wide content has logical priority [Lewis] |
| Full Idea: There is nothing to support the thesis that wide content is the only kind of content, or that it is any way pre-eminent or basic. | |
| From: David Lewis (Lewis: reduction of mind (on himself) [1994], p.424) | |
| A reaction: The idea that all content is 'wide' seems quite wrong. We can't all be wrong about the meaning of a word, because the underlying facts have not yet been discovered. |
| 3999 | A spontaneous duplicate of you would have your brain states but no experience, so externalism would deny him any beliefs [Lewis] |
| Full Idea: According to externalists, Davidson's 'swampman' is your exact duplicate in brains states, but hasn't had time to become acquainted with much, so he has virtually no beliefs. | |
| From: David Lewis (Lewis: reduction of mind (on himself) [1994], p.425) | |
| A reaction: An implausible fantasy, but it does highlight the fact that beliefs and concepts are primarily internal states. |
| 4000 | Wide content derives from narrow content and relationships with external things [Lewis] |
| Full Idea: Wide content is derivative, a product of narrow content and relationships of acquaintance with external things. | |
| From: David Lewis (Lewis: reduction of mind (on himself) [1994], p.430) | |
| A reaction: I would say: content is a mental state, but it is created and fixed by a community, and wide content is the part fixed by experts in the community. We can all be wrong about meanings, and occasionally most of us are wrong about a specialised meaning. |