Combining Texts

Ideas for 'fragments/reports', 'On the Plurality of Worlds' and 'works'

unexpand these ideas     |    start again     |     choose another area for these texts

display all the ideas for this combination of texts

---

10 ideas

9. Objects / C. Structure of Objects / 8. Parts of Objects / c. Wholes from parts

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?

9. Objects / D. Essence of Objects / 7. Essence and Necessity / a. Essence as necessary properties

13793	An essential property is one possessed by all counterparts [Lewis, by Elder]
	Full Idea: For Lewis, if a property possessed by a given individual or kind is missing in some of the contextually relevant counterparts, that property is accidental to the individual or kind; if it is possessed by all of them, that property is essential.
	From: report of David Lewis (On the Plurality of Worlds [1986], 248-263) by Crawford L. Elder - Real Natures and Familiar Objects 1.4
	A reaction: This is a sophisticated version of the idea that essential properties are just necessary properties. It might make sense with a very sparse view of properties (mainly causal ones), but I think of essences as quite different from necessities.

9. Objects / E. Objects over Time / 1. Objects over Time

9663	A thing 'perdures' if it has separate temporal parts, and 'endures' if it is wholly present at different times [Lewis]
	Full Idea: Something 'perdures' iff it persists by having different temporal parts, or stages, at different times, though no one part of it is wholly present at more than one time; whereas it 'endures' iff it persists by being wholly present at more than one time.
	From: David Lewis (On the Plurality of Worlds [1986], 4.2)
	A reaction: Only a philosopher would come up with a concept like perdurance. I'm thinking about this one, and will get back to you in a later-numbered idea... He compares perdurance to the way a road persists through space.

9. Objects / E. Objects over Time / 2. Objects that Change

14737	Properties cannot be relations to times, if there are temporary properties which are intrinsic [Lewis, by Sider]
	Full Idea: The problem of 'temporary intrinsics' is that in one model we think of properties as relations to times (I am 'bent' relative to now), but change sometime involves intrinsic properties. I am just plain bent, not bent with respect to something else.
	From: report of David Lewis (On the Plurality of Worlds [1986], p.202-4) by Theodore Sider - Four Dimensionalism
	A reaction: [I've compressed Sider's summary] The question of whether intrinsic properties endure over time runs in parallel with the question of whether objects endure over time, and the two issues cannot be separated.

9. Objects / E. Objects over Time / 3. Three-Dimensionalism

9664	Endurance is the wrong account, because things change intrinsic properties like shape [Lewis]
	Full Idea: The principal and decisive objection to endurance, as an account of the persistence of ordinary things, is the problem of temporary intrinsics. Persisting things change their intrinsic properties, such as their shape. My own shape keeps changing.
	From: David Lewis (On the Plurality of Worlds [1986], 4.2)
	A reaction: Presumably if something was going to endure through time it would need a shape. If it has no particular shape, it lacks identity? Lewis discusses the problem at length. Why is a precise shape essential to anything?

9665	There are three responses to the problem that intrinsic shapes do not endure [Lewis]
	Full Idea: The problem for the endurance view of temporary intrinsic properties like shape is met be either saying shape is a disguised relational property, or only present properties are intrinsic, or the shapes belong to different things (perdurance).
	From: David Lewis (On the Plurality of Worlds [1986], 4.2)
	A reaction: [compressed] It is certainly implausible to deny that shape is a feature of all physical objects. Or it appears to be. Shapes are hard to pin down at the quantum level. How do you sharply divide moments for the perdurance view? ...

9. Objects / E. Objects over Time / 12. Origin as Essential

19280	I can ask questions which create a context in which origin ceases to be essential [Lewis]
	Full Idea: If I ask how things would be if Saul Kripke had come from no sperm and egg, but was brought by a stork, that makes sense. I create a context that makes my question make sense, which is a context that makes origin not to be essential.
	From: David Lewis (On the Plurality of Worlds [1986], 4.5)
	A reaction: I'm not clear why delivery by a stork doesn't just count as a different origin, and hence it turns out to be essential to Kripke. If Kripke were a necessary being (and he's a good candidate), then he would have no origin.

9. Objects / F. Identity among Objects / 5. Self-Identity

15968	Identity is simple - absolutely everything is self-identical, and nothing is identical to another thing [Lewis]
	Full Idea: Identity is utterly simple and unproblematic. Everything is identical to itself; nothing is ever identical to anything except itself. There is never any problem about what makes something identical to itself; nothing can ever fail to be.
	From: David Lewis (On the Plurality of Worlds [1986], 4.1)
	A reaction: I have great problems with expressing this concept as a thing being 'identical to itself'. I will always say that it 'has an identity'. But then it is problematical, because what constitutes an identity? When do dispersing clouds lose it?

9. Objects / F. Identity among Objects / 6. Identity between Objects

15969	Two things can never be identical, so there is no problem [Lewis]
	Full Idea: There is never any problem about what makes two things identical; two things can never be identical.
	From: David Lewis (On the Plurality of Worlds [1986], 4.1)
	A reaction: This expresses Lewis's preference for usage of the word 'identity', rather than a simple solution. It pays no attention to type-identity, which is an obvious phenomenon. In some sense, it is just obvious that two electrons are 'identical'.