display all the ideas for this combination of philosophers
24 ideas
| 15452 | We could not uphold a truthmaker for 'Fa' without structures [Lewis] |
| Full Idea: We could not, without structures, uphold the principle that every truth has a truthmaker. If Fa is true, the truthmaker is not F, not a, nor both together; not their mereological sum; not a set-theoretic construction. These would exist just the same. | |
| From: David Lewis (Comment on Armstrong and Forrest [1986], p.109) | |
| A reaction: This point ought to trouble Lewis, as well as Armstrong and Forrest. If we assert 'Fa', we must (in any theory) have some idea of what unites them, as well as of their separate existence. It must a fact about 'a', not a fact about 'F'. |
| 15448 | The 'magical' view of structural universals says they are atoms, even though they have parts [Lewis] |
| Full Idea: The 'magical' conception of structural universals says 'simple' must be distinguished from 'atomic'. A structural universal is never simple; it involves other, simpler, universals, but it is mereologically atomic. The other universals are not its parts. | |
| From: David Lewis (Against Structural Universals [1986], 'The magical') | |
| A reaction: Hence the 'magic' is for it to be an indissoluble unity, while acknowledging that it has parts. Personally I don't see much problem with this view, since universals already perform the magical feat of being 'instantiated', whatever that means. |
| 15449 | If 'methane' is an atomic structural universal, it has nothing to connect it to its carbon universals [Lewis] |
| Full Idea: What is it about the universal carbon that gets it involved in necessary connections with methane? Why not rubidium instead? The universal 'carbon' has nothing more in common with the universal methane than the universal rubidium has! | |
| From: David Lewis (Against Structural Universals [1986], 'The magical') | |
| A reaction: This is his objection to the 'magical' unity of structural universals. The point is that if methane is an atomic unity, as claimed, it can't have anything 'in common' with its components. |
| 15439 | The 'pictorial' view of structural universals says they are wholes made of universals as parts [Lewis] |
| Full Idea: On the 'pictorial' conception, a structural universal is isomorphic to its instances. ...It is an individual, a mereological composite, not a set. ...It is composed of simpler universals which are literally parts of it. | |
| From: David Lewis (Against Structural Universals [1986], 'The pictorial') | |
| A reaction: I'm not clear why Lewis labels this the 'pictorial' view. His other two views of structural universals are 'linguistic' and 'magical'. The linguistic is obviously wrong, and the magical doesn't sound promising. Must I vote for pictorial? |
| 15441 | The structural universal 'methane' needs the universal 'hydrogen' four times over [Lewis] |
| Full Idea: What is wrong with the pictorial conception is that if the structural universal 'methane' is to be an isomorph of the molecules that are its instances, it must have the universal 'hydrogen' as a part not just once, but four times over. | |
| From: David Lewis (Against Structural Universals [1986], 'The pictorial') | |
| A reaction: The point is that if hydrogen is a universal it must be unique, so there can't be four of them. To me this smacks of the hopeless mess theologians get into, because of bad premisses. Drop universals, and avoid this kind of stuff. |
| 15445 | Butane and Isobutane have the same atoms, but different structures [Lewis] |
| Full Idea: The stuctural universal 'isobutane' consists of the universal carbon four times over, hydrogen ten times over, and the universal 'bonded' thirteen times over - just like the universal 'butane'. | |
| From: David Lewis (Against Structural Universals [1986], 'Variants') | |
| A reaction: The point is that isobutane and butane have the same components in different structures. At least this is Lewis facing up to the problem of the 'flatness' of mereological wholes. |
| 15434 | Structural universals have a necessary connection to the universals forming its parts [Lewis] |
| Full Idea: There is a necessary connection between the instantiating of a structural universal by the whole and the instantiating of other universals by its parts. We can call the relation 'involvement', a nondescript word. | |
| From: David Lewis (Against Structural Universals [1986], 'What are') | |
| A reaction: In the case of a shape, I suppose the composing 'universals' [dunno what they are] will all be essential to the shape - that is, part of the very nature of the thing, loss of which would destroy the identity. |
| 15437 | We can't get rid of structural universals if there are no simple universals [Lewis] |
| Full Idea: We can't dispense with structural universals if we cannot be sure that there are any simples which can be involved in them. | |
| From: David Lewis (Against Structural Universals [1986], 'Why believe') | |
| A reaction: Lewis cites this as Armstrong's strongest reason for accepting structural universals (and he takes their requirement for an account of laws of nature as the weakest). I can't comprehend a world that lacks underlying simplicity. |
| 15446 | Composition is not just making new things from old; there are too many counterexamples [Lewis] |
| Full Idea: Not just any operation that makes new things from old is a form of composition! There is no sense in which my parents are part of me, and no sense in which two numbers are parts of their greatest common factor. | |
| From: David Lewis (Against Structural Universals [1986], 'Variants') | |
| A reaction: One of those rare moments when David Lewis seems to have approached a really sensible metaphysics. Further on he rejects all forms of composition apart from mereology. |
| 14748 | The many are many and the one is one, so they can't be identical [Lewis] |
| Full Idea: What is true of the many is not exactly what is true of the one. After all they are many while it is one. The number of the many is six, whereas the number of the fusion is one. The singletons of the many are distinct from the singleton of the one. | |
| From: David Lewis (Parts of Classes [1991], 3.6) | |
| A reaction: I wouldn't take this objection to be conclusive. 'Some pebbles' seem to be many, but a 'handful of pebbles' seem to be one, where the physical situation might be identical. If they are not identical, then the non-identity is purely conceptual. |
| 6129 | Lewis affirms 'composition as identity' - that an object is no more than its parts [Lewis, by Merricks] |
| Full Idea: Lewis says that the parts of a thing are identical with the whole they compose, calling his view 'composition as identity', which is the claim that a physical object is 'nothing over and above its parts'. | |
| From: report of David Lewis (Parts of Classes [1991], p.84-7) by Trenton Merricks - Objects and Persons §I.IV | |
| A reaction: The ontological economy of this view is obviously attractive, but I don't agree with it. You certainly can't say that all identity consists entirely of composition by parts, because the parts need identity to get the view off the ground. |
| 14210 | A gerrymandered mereological sum can be a mess, but still have natural joints [Lewis] |
| Full Idea: The mereological sum of the coffee in my cup, the ink in this sentence, a nearby sparrow, and my left shoe is a miscellaneous mess of an object, yet its boundaries are by no means unrelated to the joints of nature. | |
| From: David Lewis (Putnam's Paradox [1984], 'What Might') | |
| A reaction: In that case they do, but if there are no atoms at the root of physics then presumably their could also be thoroughly jointless assemblages, involving probability distributions etc. Even random scattered atoms seem rather short of joints. |
| 15512 | In mereology no two things consist of the same atoms [Lewis] |
| Full Idea: It is a principle of mereology that no two things consist of exactly the same atoms. | |
| From: David Lewis (Parts of Classes [1991], 2.3) | |
| A reaction: The problem with this is screamingly obvious - that the same atoms might differ in structure. Lewis did refer to this problem, but seems to try to wriggle out of it, in Idea 15444. |
| 15519 | Trout-turkeys exist, despite lacking cohesion, natural joints and united causal power [Lewis] |
| Full Idea: A trout-turkey is inhomogeneous, disconnected, not in contrast with its surroundings. It is not cohesive, not causally integrated, not a causal unit in its impact on the rest of the world. It is not carved at the joints. That doesn't affect its existence. | |
| From: David Lewis (Parts of Classes [1991], 3.5) | |
| A reaction: A nice pre-emptive strike against all the reasons why anyone might think more is needed for unity than a mereological fusion. |
| 15521 | Given cats, a fusion of cats adds nothing further to reality [Lewis] |
| Full Idea: Given a prior commitment to cats, a commitment to cat-fusions is not a further commitment. The fusion is nothing over and above the cats that compose it. It just is them. They just are it. Together or separately, the cats are the same portion of Reality. | |
| From: David Lewis (Parts of Classes [1991], 3.6) | |
| A reaction: The two extremes of ontology are that there are no objects, or that every combination is an object. Until reading this I thought Lewis was in the second camp, but this sounds like object-nihilism, as in Van Inwagen and Merricks. |
| 15522 | The one has different truths from the many; it is one rather than many, one rather than six [Lewis] |
| Full Idea: What's true of the many is not exactly what's true of the one. After all they are many while it is one. The number of the many is six, whereas the number of the fusion is one. | |
| From: David Lewis (Parts of Classes [1991], 3.6) | |
| A reaction: Together with Idea 15521, this nicely illustrates the gulf between commitment to ontology and commitment to truths. The truths about a fusion change, while its ontology remains the same. Possibly this is the key to all of metaphysics. |
| 14244 | Lewis only uses fusions to create unities, but fusions notoriously flatten our distinctions [Oliver/Smiley on Lewis] |
| Full Idea: Lewis employs mereological fusion as his sole method of making one thing out of many, and fusion is notorious for the way it flattens out and thereby obliterates distinctions. | |
| From: comment on David Lewis (Parts of Classes [1991]) by Oliver,A/Smiley,T - What are Sets and What are they For? 3.1 | |
| A reaction: I take this to be a key point in the discussion of mereology in ontological contexts. As a defender of intrinsic structural essences, I have no use for mereological fusions, and look for a quite different identity for 'wholes'. |
| 10660 | A commitment to cat-fusions is not a further commitment; it is them and they are it [Lewis] |
| Full Idea: Given a prior commitment to cats, a commitment to cat-fusions is not a further commitment. The fusion is nothing over and above the cats that compose it. It just is them. They just are it. | |
| From: David Lewis (Parts of Classes [1991], p.81), quoted by Achille Varzi - Mereology 4.3 | |
| A reaction: I take this to make Lewis a nominalist, saying the same thing that Goodman said about Utah in Idea 10657. Any commitment to cat-fusions being more than the cats, or Utah being more than its counties, strikes me as crazy. |
| 10810 | I say that absolutely any things can have a mereological fusion [Lewis] |
| Full Idea: I accept the principle of Unrestricted Composition: whenever there are some things, no matter how many or how unrelated or how disparate in character they may be, they have a mereological fusion. ...The trout-turkey is part fish and part fowl. | |
| From: David Lewis (Mathematics is Megethology [1993], p.07) | |
| A reaction: This nicely ducks the question of when things form natural wholes and when they don't, but I would have thought that that might be one of the central issues of metaphysicals, so I think I'll give Lewis's principle a miss. |
| 9667 | Mereological composition is unrestricted: any class of things has a mereological sum [Lewis] |
| Full Idea: I claim that mereological composition is unrestricted: any old class of things has a mereological sum. Whenever there are some things, even out of different possible worlds, there is something composed of just those things. | |
| From: David Lewis (On the Plurality of Worlds [1986], 4.3) | |
| A reaction: To say the least, a rather unusual usage for the English word 'thing'. I presume that Lewis is in the grip of a slippery slope problem - that there is no way to define the borderline between things and non-things. Presumably 'class' is unrestricted too. |
| 13268 | There are no restrictions on composition, because they would be vague, and composition can't be vague [Lewis, by Sider] |
| Full Idea: Lewis says that if not every class has a fusion then there must be a restriction on composition. The only plausible restrictions would be vague ones, which is impossible, because then whether composition occurs would be vague. So every class has a fusion. | |
| From: report of David Lewis (On the Plurality of Worlds [1986], p.212-3) by Theodore Sider - Four Dimensionalism 9.1 | |
| A reaction: This is Lewis's key argument in favour of unrestricted composition, his Vagueness Argument. Why can't composition be vague? If you gradually reassemble a broken mirror, at what point does the mirror acquire its unity? |
| 15440 | A whole is distinct from its parts, but is not a further addition in ontology [Lewis] |
| Full Idea: A whole is an extra item in our ontology only in the minimal sense that it is not identical to any of its proper parts; but it is not distinct from them either, so when we believe in the parts it is no extra burden to believe in the whole. | |
| From: David Lewis (Against Structural Universals [1986], 'The pictorial') | |
| A reaction: A little confusing, to be 'not identical' and yet 'not different'. As Lewis says elsewhere, the whole is one, and the parts are not. A crux. Essentialism implies a sort of holism, that parts with a structure constitute a new thing. |
| 15444 | Different things (a toy house and toy car) can be made of the same parts at different times [Lewis] |
| Full Idea: Different things can be made of the same parts at different times, as when the tinkertoy house is taken apart and put back together as a tinkertoy car. | |
| From: David Lewis (Against Structural Universals [1986], 'Variants') | |
| A reaction: More important than it looks! This is Lewis's evasion of the question of the structure of the parts. Times will individuate different structures, but if I take type-identical parts and make a house and a car simultaneously, are they type-identical? |
| 10566 | Lewis prefers giving up singletons to giving up sums [Lewis, by Fine,K] |
| Full Idea: In the face of the conflict between mereology and set theory, Lewis has advocated giving up the existence of singletons rather than sums. | |
| From: report of David Lewis (Parts of Classes [1991]) by Kit Fine - Replies on 'Limits of Abstraction' 1 |