15 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. |
| 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. |
| 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 |
| 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. |
| 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. |
| 1748 | Archelaus was the first person to say that the universe is boundless [Archelaus, by Diog. Laertius] |
| Full Idea: Archelaus was the first person to say that the universe is boundless. | |
| From: report of Archelaus (fragments/reports [c.450 BCE]) by Diogenes Laertius - Lives of Eminent Philosophers 02.Ar.3 |
| 18202 | The concept of a field gradually replaced the substances in explaining relations between charges [Einstein/Infeld] |
| Full Idea: In the beginning the field concept was no more than a means of facilitating the understanding of phenomena. ...In the new field language it is the field and not the charges themselves which is essential. The substance was overshadowed by the field. | |
| From: Einstein,A/Infeld,L (The Evolution of Physics [1938], p.151), quoted by Penelope Maddy - Naturalism in Mathematics II.4 | |
| A reaction: This is very important for philosophical metaphysicians, especially those like me who want to explain the universe by the nature of the stuff that composes it. The 'stuff' had better not be simplistic individual 'substances'. |
| 5989 | Archelaus said life began in a primeval slime [Archelaus, by Schofield] |
| Full Idea: Archelaus wrote that life on Earth began in a primeval slime. | |
| From: report of Archelaus (fragments/reports [c.450 BCE]) by Malcolm Schofield - Archelaus | |
| A reaction: This sounds like a fairly clearcut assertion of the production of life by evolution. Darwin's contribution was to propose the mechanism for achieving it. We should honour the name of Archelaus for this idea. |