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15537
|
If cats are vague, we deny that the many cats are one, or deny that the one cat is many [Lewis]
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Full Idea:
To deny that there are many cats on the mat (because removal of a few hairs seems to produce a new one), we must either deny that the many are cats, or else deny that the cats are many. ...I think both alternatives lead to successful solutions.
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From:
David Lewis (Many, but almost one [1993], 'The paradox')
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A reaction:
He credits the problem to Geach (and Tibbles), and says it is the same as Unger's 'problem of the many' (Idea 15536).
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15452
|
We could not uphold a truthmaker for 'Fa' without structures [Lewis]
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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.
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From:
David Lewis (Comment on Armstrong and Forrest [1986], p.109)
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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'.
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15448
|
The 'magical' view of structural universals says they are atoms, even though they have parts [Lewis]
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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.
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From:
David Lewis (Against Structural Universals [1986], 'The magical')
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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.
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15441
|
The structural universal 'methane' needs the universal 'hydrogen' four times over [Lewis]
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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.
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From:
David Lewis (Against Structural Universals [1986], 'The pictorial')
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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.
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14748
|
The many are many and the one is one, so they can't be identical [Lewis]
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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.
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From:
David Lewis (Parts of Classes [1991], 3.6)
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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.
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6129
|
Lewis affirms 'composition as identity' - that an object is no more than its parts [Lewis, by Merricks]
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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'.
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From:
report of David Lewis (Parts of Classes [1991], p.84-7) by Trenton Merricks - Objects and Persons §I.IV
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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.
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14210
|
A gerrymandered mereological sum can be a mess, but still have natural joints [Lewis]
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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.
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From:
David Lewis (Putnam's Paradox [1984], 'What Might')
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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.
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15519
|
Trout-turkeys exist, despite lacking cohesion, natural joints and united causal power [Lewis]
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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.
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From:
David Lewis (Parts of Classes [1991], 3.5)
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A reaction:
A nice pre-emptive strike against all the reasons why anyone might think more is needed for unity than a mereological fusion.
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15521
|
Given cats, a fusion of cats adds nothing further to reality [Lewis]
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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.
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|
From:
David Lewis (Parts of Classes [1991], 3.6)
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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.
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14244
|
Lewis only uses fusions to create unities, but fusions notoriously flatten our distinctions [Oliver/Smiley on Lewis]
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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.
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From:
comment on David Lewis (Parts of Classes [1991]) by Oliver,A/Smiley,T - What are Sets and What are they For? 3.1
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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'.
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13268
|
There are no restrictions on composition, because they would be vague, and composition can't be vague [Lewis, by Sider]
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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.
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|
From:
report of David Lewis (On the Plurality of Worlds [1986], p.212-3) by Theodore Sider - Four Dimensionalism 9.1
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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?
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15440
|
A whole is distinct from its parts, but is not a further addition in ontology [Lewis]
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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.
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From:
David Lewis (Against Structural Universals [1986], 'The pictorial')
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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.
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13793
|
An essential property is one possessed by all counterparts [Lewis, by Elder]
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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.
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|
From:
report of David Lewis (On the Plurality of Worlds [1986], 248-263) by Crawford L. Elder - Real Natures and Familiar Objects 1.4
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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.
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9663
|
A thing 'perdures' if it has separate temporal parts, and 'endures' if it is wholly present at different times [Lewis]
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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.
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|
From:
David Lewis (On the Plurality of Worlds [1986], 4.2)
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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.
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14737
|
Properties cannot be relations to times, if there are temporary properties which are intrinsic [Lewis, by Sider]
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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.
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|
From:
report of David Lewis (On the Plurality of Worlds [1986], p.202-4) by Theodore Sider - Four Dimensionalism
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|
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.
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9664
|
Endurance is the wrong account, because things change intrinsic properties like shape [Lewis]
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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.
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|
From:
David Lewis (On the Plurality of Worlds [1986], 4.2)
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|
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?
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19280
|
I can ask questions which create a context in which origin ceases to be essential [Lewis]
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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.
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|
From:
David Lewis (On the Plurality of Worlds [1986], 4.5)
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|
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.
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