20 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. |
| 13804 | A property is essential iff the object would not exist if it lacked that property [Forbes,G] |
| Full Idea: A property P is an essential property of an object x iff x could not exist and lack P, that is, as they say, iff x has P at every world at which x exists. | |
| From: Graeme Forbes (In Defense of Absolute Essentialism [1986], 1) | |
| A reaction: This immediately places the existence of x outside the normal range of its properties, so presumably 'existence is not a predicate', but that dictum may be doubted. As it stands this definition will include trivial and vacuous properties. |
| 13805 | Properties are trivially essential if they are not grounded in a thing's specific nature [Forbes,G] |
| Full Idea: Essential properties may be trivial or nontrivial. It is characteristic of P's being trivially essential to x that x's possession of P is not grounded in the specific nature of x. | |
| From: Graeme Forbes (In Defense of Absolute Essentialism [1986], 2) | |
| A reaction: This is where my objection to the modal view of essence arises. How is he going to explain 'grounded' and 'specific nature' without supplying an entirely different account of essence? |
| 13808 | A relation is essential to two items if it holds in every world where they exist [Forbes,G] |
| Full Idea: A relation R is essential to x and y (in that order) iff Rxy holds at every world where x and y both exist. | |
| From: Graeme Forbes (In Defense of Absolute Essentialism [1986], 2) | |
| A reaction: I find this bizarre. Not only does this seem to me to have nothing whatever to do with essence, but also the relation might hold even though it is a purely contingent matter. All rabbits are a reasonable distance from the local star. Essence of rabbit? |
| 13806 | Trivially essential properties are existence, self-identity, and de dicto necessities [Forbes,G] |
| Full Idea: The main groups of trivially essential properties are (a) existence, self-identity, or their consequences in S5; and (b) properties possessed in virtue of some de dicto necessary truth. | |
| From: Graeme Forbes (In Defense of Absolute Essentialism [1986], 2) | |
| A reaction: He adds 'extraneously essential' properties, which also strike me as being trivial, involving relations. 'Is such that 2+2=4' or 'is such that something exists' might be necessary, but they don't, I would say, have anything to do with essence. |
| 13807 | A property is 'extraneously essential' if it is had only because of the properties of other objects [Forbes,G] |
| Full Idea: P is 'extraneously essential' to x iff it is possessed by x at any world w only in virtue of the possession at w of certain properties by other objects. | |
| From: Graeme Forbes (In Defense of Absolute Essentialism [1986], 2) | |
| A reaction: I would say that these are the sorts of properties which have nothing to do with being essential, even if they are deemed to be necessary. |
| 13809 | One might be essentialist about the original bronze from which a statue was made [Forbes,G] |
| Full Idea: In the case of artefacts, there is an essentialism about original matter; for instance, it would be said of any particular bronze statue that it could not have been cast from a totally different quantity of bronze. | |
| From: Graeme Forbes (In Defense of Absolute Essentialism [1986], 3) | |
| A reaction: Forbes isn't endorsing this, and it doesn't sound convincing. He quotes the thought 'I wish I had made this pot from a different piece of clay'. We might corrupt a statue by switching bronze, but I don't think the sculptor could do so. |
| 13810 | The source of de dicto necessity is not concepts, but the actual properties of the thing [Forbes,G] |
| Full Idea: It is widely held that the source of de dicto necessity is in concepts, ..but I deny this... even with simple de dicto necessities, the source of the necessity is to be found in the properties to which the predicates of the de dicto truth refer. | |
| From: Graeme Forbes (In Defense of Absolute Essentialism [1986], 3) | |
| A reaction: It is normal nowadays to say this about de re necessities, but this is more unusual. |
| 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. |
| 20761 | If existence is absurd it can never have a meaning [Beauvoir] |
| Full Idea: To declare that existence is absurd is to deny that it can ever be given a meaning; to say that it is ambiguous is to assert that its meaning is never fixed. | |
| From: Simone de Beauvoir (Ethics of Ambiguity [1948], p.129), quoted by Kevin Aho - Existentialism: an introduction 6 'Bad' | |
| A reaction: Absurdity precludes meaning, but being meaningless doesn't entail absurdity. Asteroids are meaningless. Presumably if existence is meaningless now (as in a depression), but it might possibly become meaningful, then it can't qualify as 'absurd'. |