display all the ideas for this combination of texts
23 ideas
| 9660 | The impossible can be imagined as long as it is a bit vague [Lewis] |
| Full Idea: Imaginability is a poor criterion of possibility. We can imagine the impossible provided we do not imagine it in perfect detail and all the time. | |
| From: David Lewis (On the Plurality of Worlds [1986], 1.8) | |
| A reaction: In general I agree, but Williamson nicely opposes this view. The fact is that we derive most of our understanding of what is possible from imagination. We just have to realise that we can get it wrong, and so must attend to detail. |
| 9669 | There are no free-floating possibilia; they have mates in a world, giving them extrinsic properties [Lewis] |
| Full Idea: There are no free-floating possibilia. Every possibility is part of a world - exactly one world - and thus comes surrounded by worldmates, and fully equipped with extrinsic properties in virtue of its relations to them. | |
| From: David Lewis (On the Plurality of Worlds [1986], 4.4) | |
| A reaction: This is a key claim in the possible worlds understanding of modality, contrary to the more common sense and normal language claim that a possibility is an isolated thing. |
| 16133 | Possible worlds can contain contradictions if such worlds are seen as fictions [Lewis] |
| Full Idea: If worlds were like stories or story-tellers, there would indeed be room for worlds according to which contradictions are true. | |
| From: David Lewis (On the Plurality of Worlds [1986], 1.2 n3) | |
| A reaction: Most existing fictions contain tiny contradictions, but we might ask whether that thereby disqualifies them from depicting genuinely 'possible' worlds. |
| 16132 | On mountains or in worlds, reporting contradictions is contradictory, so no such truths can be reported [Lewis] |
| Full Idea: To tell the alleged truth about contradictory things that happen on a mountain is just contradicting yourself, but you can't tell the truth by contradicting yourself. There is no mountain where contradictions are true, and impossible worlds are no better. | |
| From: David Lewis (On the Plurality of Worlds [1986], 1.2 n3) | |
| A reaction: [compressed] He says this works for any 'restricted' domain like a mountain or a real world, but that it wouldn't apply in an unrestricted fictional world. |
| 16283 | For me, all worlds are equal, with each being actual relative to itself [Lewis] |
| Full Idea: For me, all the worlds are on an equal footing in that each is actual relative to itself and none is actual relative to any other. | |
| From: David Lewis (On the Plurality of Worlds [1986], 3.1) | |
| A reaction: Lewis says the world we call 'actual' is simply a matter of how our indexicals refer. That sounds the wrong way round to me (as so often with Lewis). |
| 12255 | For Lewis there is no real possibility, since all possibilities are actual [Oderberg on Lewis] |
| Full Idea: Lewis-style modal realism eliminates all real possibility since on his account everything is actual relative to its own world. | |
| From: comment on David Lewis (On the Plurality of Worlds [1986]) by David S. Oderberg - Real Essentialism 6.2 | |
| A reaction: Since it is possible for me to be in New York and in Chicago, but not both at once, his possibilities have to be kept apart, even though they are actual. I expect my visit to Chicago to remain as only a possibility. |
| 9219 | Lewis posits possible worlds just as Quine says that physics needs numbers and sets [Lewis, by Sider] |
| Full Idea: Lewis's argument for possible worlds parallels Quine's for the existence of sets: our best overall empirical theory, mathematical physics, quantifies over real numbers, so we have reason to posit real numbers, or the sets to which they may be reduced. | |
| From: report of David Lewis (On the Plurality of Worlds [1986]) by Theodore Sider - Reductive Theories of Modality 3.6 | |
| A reaction: They both strike me as suspect. Indeed, the extreme implausibility of Lewis's conclusion throws doubt on Quine's original strategy. I'm happy to work with sets and possible worlds, and only worry about ontological commitment at a later stage. |
| 15022 | If possible worlds really exist, then they are part of actuality [Sider on Lewis] |
| Full Idea: The familiar complaint against Lewis is that if his worlds existed, they'd be part of actuality. | |
| From: comment on David Lewis (On the Plurality of Worlds [1986]) by Theodore Sider - Writing the Book of the World 11.5 | |
| A reaction: Sider presents that as rather superficial, but it sounds a pretty good objection to me. Lewis would note that only our world has the indexical features which he says pick out actuality. Real possible worlds might lack indexical features? |
| 10469 | A world is a maximal mereological sum of spatiotemporally interrelated things [Lewis] |
| Full Idea: A world is a maximal mereological sum of spatiotemporally interrelated things. | |
| From: David Lewis (On the Plurality of Worlds [1986], 1.6) | |
| A reaction: (I wonder what Lewis's account of space was?) A mereological sum is "the least inclusive thing that includes all the parts" (p.69). It is maximal when all 'worldmates' are parts. But then 'worldmates' are defined as parts, so it threatens circularity. |
| 16441 | Lewis rejects actualism because he identifies properties with sets [Lewis, by Stalnaker] |
| Full Idea: It is the identification of properties with sets that rules out, for Lewis, an actualist account of possible worlds. | |
| From: report of David Lewis (On the Plurality of Worlds [1986]) by Robert C. Stalnaker - Mere Possibilities 1.1 | |
| A reaction: I suppose the sets which are the properties have to include all the possible red things as well as the actual one. This escapes the renate/cordate problem. |
| 16282 | Ersatzers say we have one world, and abstract representations of how it might have been [Lewis] |
| Full Idea: The ersatzers say that instead of an incredible plurality of concrete worlds, we can have one world only, and countless abstract entities representing ways that this world might have been. | |
| From: David Lewis (On the Plurality of Worlds [1986], 3.1) | |
| A reaction: Put me down as an ersatzer. They seem to be the same as Actualists. Are worlds other possible worlds, or ways 'this world might have been'? Not the same. Does actuality constrain what is possible? (Barcan formula?) |
| 16284 | Ersatz worlds represent either through language, or by models, or magically [Lewis] |
| Full Idea: I distinguish three principal ways ersatz worlds represent: linguistic, in which they are like stories or theories; pictorial, like pictures or isomorphic scale models; or magical, in which it is just their nature to represent. | |
| From: David Lewis (On the Plurality of Worlds [1986], 3.1) | |
| A reaction: I think I incline to the 'model' view. The linguistic version means animals can't assess possibilities. I take modelling to be basic to what a mind is, and what a mind is for. |
| 16286 | Linguistic possible worlds need a complete supply of unique names for each thing [Lewis] |
| Full Idea: There are two difficulties with Carnap's taking possible worlds as linguistic. Everything must have a name, or our state-descriptions will be silent about nameless things, and nothing may have two names, or we may affirm and deny a predicate of one thing. | |
| From: David Lewis (On the Plurality of Worlds [1986], 3.2) | |
| A reaction: The idea of possible worlds as linguistic has no appeal for me, so this problem doesn't surprise or bother me, but it sounds fairly terminal for the project. |
| 16287 | Maximal consistency for a world seems a modal distinction, concerning what could be true together [Lewis] |
| Full Idea: An ersatz world must be maximally consistent (hence destroyed by an additional sentences), …but that is prima facie a modal distinction: a set of sentences is consistent iff those sentences, as interpreted, could all be true together. | |
| From: David Lewis (On the Plurality of Worlds [1986], 3.2) | |
| A reaction: This is indicative of Lewis's motivation for his project, which is to eliminate modal facts from the world. Only a vast multitude of non-modal concrete worlds can satisfy all the contraints. Cf many-worlds quantum mechanics for non-locality. |
| 9662 | Linguistic possible worlds have problems of inconsistencies, no indiscernibles, and vocabulary [Lewis] |
| Full Idea: Linguistic representations of possible worlds have three problems: some descriptions are inconsistent (which worlds cannot be); we cannot have indiscernible descriptions (though some worlds might be so); and descriptions are limited by vocabulary. | |
| From: David Lewis (On the Plurality of Worlds [1986], 3.2) | |
| A reaction: Lewis is wonderful at getting problems clearly on the table. I take the idea of possible worlds as linguistic entities to be a non-starter, because (as usual) animals do it too, when they think of possibilities, which even the dimmest ones must do. |
| 7690 | If sets exist, then defining worlds as proposition sets implies an odd distinction between existing and actual [Jacquette on Lewis] |
| Full Idea: If sets exist, then the conventional concept of a logically possible world as a proposition set requires a counterintuitive distinction between existence and actuality, between what exists and what is actual. | |
| From: comment on David Lewis (On the Plurality of Worlds [1986]) by Dale Jacquette - Ontology Ch.2 | |
| A reaction: This pinpoints the obvious difficulty that most people have with Lewis's claim that possible worlds exist. Russell's claim that universals 'subsist' (Idea 5409) is a similar attempt to have two different sorts of existence in your ontology. |
| 14404 | The counterpart relation is sortal-relative, so objects need not be a certain way [Lewis, by Merricks] |
| Full Idea: Lewis takes the counterpart relation to be sortal-relative, so he (no less than Quine) denies that objects, qua existing, are necessarily a certain way. | |
| From: report of David Lewis (On the Plurality of Worlds [1986]) by Trenton Merricks - Truth and Ontology 5.III n10 | |
| A reaction: Does this mean that there could be two different versions of the same possible world (certainly not!), or that worlds are entirely created by our concepts rather than by what is actually possible. |
| 5440 | A counterpart in a possible world is sufficiently similar, and more similar than anything else [Lewis, by Mautner] |
| Full Idea: 'Jack could have been taller' implies a different Jack in a different world, so Lewis defines a counterpart in a possible world as an individual sufficiently similar to Jack, and more similar to Jack than anything else in that world. | |
| From: report of David Lewis (On the Plurality of Worlds [1986]) by Thomas Mautner - Penguin Dictionary of Philosophy p.115 | |
| A reaction: If we say something like "I could have been twins" or "I could have been a genius" in another world, it would need an odd concept of my personal identity for it to remain identical in those counterfactual situations. Lewis has a point. |
| 5441 | Why should statements about what my 'counterpart' could have done interest me? [Mautner on Lewis] |
| Full Idea: If I only have counterparts in possible worlds who are not identical to me, statements about what I could have done will seem irrelevant to me, because they will be about someone else. | |
| From: comment on David Lewis (On the Plurality of Worlds [1986]) by Thomas Mautner - Penguin Dictionary of Philosophy p.115 | |
| A reaction: We might rephrase the statement as "I could have been the person who did x". Presumably my counterpart is not just any stranger, but someone I could have been. "I could have been a brick" - now that seems irrelevant to me! |
| 16291 | In counterpart theory 'Humphrey' doesn't name one being, but a mereological sum of many beings [Lewis] |
| Full Idea: For the counterpart theorist, the trick is to say that 'Humphrey' names not the Humphrey of our world, and not the Humphrey of another, but rather the trans-world individual who is the mereological sum of all those local Humphreys. | |
| From: David Lewis (On the Plurality of Worlds [1986], 4.1) | |
| A reaction: On Lewis's perdurantism Humphrey is a 'spacetime worm' across his lifetime. Now we are adding all the possible Humphreys to the sum. I'm losing track of Humphrey's shape. |
| 11903 | Extreme haecceitists could say I might have been a poached egg, but it is too remote to consider [Lewis, by Mackie,P] |
| Full Idea: Lewis's strategy for defending extreme haecceitism is that supposed impossibilities (that I might have been a poached egg) could be reconstrued as genuine possibilities that are so remote from reality that they are ignored. | |
| From: report of David Lewis (On the Plurality of Worlds [1986], 239-) by Penelope Mackie - How Things Might Have Been 9.3 | |
| A reaction: Not a promising route. Wiggins asks: if you think I could have been a poached egg, start by defining more precisely this 'I' to which we are referring. The definition will blatantly exclude any possibility of my poachedegghood. |
| 15129 | Haecceitism implies de re differences but qualitative identity [Lewis] |
| Full Idea: If two worlds differ in what they represent de re concerning some individual, but do not differ qualitatively in any way, I shall call that a haecceitist difference. Haecceitism, then, says there are at least some haecceitist differences between worlds. | |
| From: David Lewis (On the Plurality of Worlds [1986], 4.4) | |
| A reaction: Lewis bases this view on Kaplan. My brief summary of this is that 'identity may be hidden'. If all electrons are different, what distinguishes them? |
| 9670 | Extreme haecceitism says you might possibly be a poached egg [Lewis] |
| Full Idea: The most extreme version of haecceitism says that anything could possibly have any qualitative character; for instance, there is a world according to which you are a poached egg. | |
| From: David Lewis (On the Plurality of Worlds [1986], 4.4) | |
| A reaction: Presumably a plausible haecceitist view would have to be combined with essentialism, given that the possibility that I might be a poached egg is beyond my intuitive grasp. |