29 ideas
| 7785 | The use of plurals doesn't commit us to sets; there do not exist individuals and collections [Boolos] |
| Full Idea: We should abandon the idea that the use of plural forms commits us to the existence of sets/classes… Entities are not to be multiplied beyond necessity. There are not two sorts of things in the world, individuals and collections. | |
| From: George Boolos (To be is to be the value of a variable.. [1984]), quoted by Henry Laycock - Object | |
| A reaction: The problem of quantifying over sets is notoriously difficult. Try http://plato.stanford.edu/entries/object/index.html. |
| 10699 | Does a bowl of Cheerios contain all its sets and subsets? [Boolos] |
| Full Idea: Is there, in addition to the 200 Cheerios in a bowl, also a set of them all? And what about the vast number of subsets of Cheerios? It is haywire to think that when you have some Cheerios you are eating a set. What you are doing is: eating the Cheerios. | |
| From: George Boolos (To be is to be the value of a variable.. [1984], p.72) | |
| A reaction: In my case Boolos is preaching to the converted. I am particularly bewildered by someone (i.e. Quine) who believes that innumerable sets exist while 'having a taste for desert landscapes' in their ontology. |
| 10225 | Monadic second-order logic might be understood in terms of plural quantifiers [Boolos, by Shapiro] |
| Full Idea: Boolos has proposed an alternative understanding of monadic, second-order logic, in terms of plural quantifiers, which many philosophers have found attractive. | |
| From: report of George Boolos (To be is to be the value of a variable.. [1984]) by Stewart Shapiro - Philosophy of Mathematics 3.5 |
| 10736 | Boolos showed how plural quantifiers can interpret monadic second-order logic [Boolos, by Linnebo] |
| Full Idea: In an indisputable technical result, Boolos showed how plural quantifiers can be used to interpret monadic second-order logic. | |
| From: report of George Boolos (To be is to be the value of a variable.. [1984], Intro) by Øystein Linnebo - Plural Quantification Exposed Intro |
| 10780 | Any sentence of monadic second-order logic can be translated into plural first-order logic [Boolos, by Linnebo] |
| Full Idea: Boolos discovered that any sentence of monadic second-order logic can be translated into plural first-order logic. | |
| From: report of George Boolos (To be is to be the value of a variable.. [1984], §1) by Øystein Linnebo - Plural Quantification Exposed p.74 |
| 10697 | Identity is clearly a logical concept, and greatly enhances predicate calculus [Boolos] |
| Full Idea: Indispensable to cross-reference, lacking distinctive content, and pervading thought and discourse, 'identity' is without question a logical concept. Adding it to predicate calculus significantly increases the number and variety of inferences possible. | |
| From: George Boolos (To be is to be the value of a variable.. [1984], p.54) | |
| A reaction: It is not at all clear to me that identity is a logical concept. Is 'existence' a logical concept? It seems to fit all of Boolos's criteria? I say that all he really means is that it is basic to thought, but I'm not sure it drives the reasoning process. |
| 13671 | Second-order quantifiers are just like plural quantifiers in ordinary language, with no extra ontology [Boolos, by Shapiro] |
| Full Idea: Boolos proposes that second-order quantifiers be regarded as 'plural quantifiers' are in ordinary language, and has developed a semantics along those lines. In this way they introduce no new ontology. | |
| From: report of George Boolos (To be is to be the value of a variable.. [1984]) by Stewart Shapiro - Foundations without Foundationalism 7 n32 | |
| A reaction: This presumably has to treat simple predicates and relations as simply groups of objects, rather than having platonic existence, or something. |
| 10267 | We should understand second-order existential quantifiers as plural quantifiers [Boolos, by Shapiro] |
| Full Idea: Standard second-order existential quantifiers pick out a class or a property, but Boolos suggests that they be understood as a plural quantifier, like 'there are objects' or 'there are people'. | |
| From: report of George Boolos (To be is to be the value of a variable.. [1984]) by Stewart Shapiro - Philosophy of Mathematics 7.4 | |
| A reaction: This idea has potential application to mathematics, and Lewis (1991, 1993) 'invokes it to develop an eliminative structuralism' (Shapiro). |
| 10698 | Plural forms have no more ontological commitment than to first-order objects [Boolos] |
| Full Idea: Abandon the idea that use of plural forms must always be understood to commit one to the existence of sets of those things to which the corresponding singular forms apply. | |
| From: George Boolos (To be is to be the value of a variable.. [1984], p.66) | |
| A reaction: It seems to be an open question whether plural quantification is first- or second-order, but it looks as if it is a rewriting of the first-order. |
| 7806 | Boolos invented plural quantification [Boolos, by Benardete,JA] |
| Full Idea: Boolos virtually patented the new device of plural quantification. | |
| From: report of George Boolos (To be is to be the value of a variable.. [1984]) by José A. Benardete - Logic and Ontology | |
| A reaction: This would be 'there are some things such that...' |
| 10700 | First- and second-order quantifiers are two ways of referring to the same things [Boolos] |
| Full Idea: Ontological commitment is carried by first-order quantifiers; a second-order quantifier needn't be taken to be a first-order quantifier in disguise, having special items, collections, as its range. They are two ways of referring to the same things. | |
| From: George Boolos (To be is to be the value of a variable.. [1984], p.72) | |
| A reaction: If second-order quantifiers are just a way of referring, then we can see first-order quantifiers that way too, so we could deny 'objects'. |
| 15435 | If you think universals are immanent, you must believe them to be sparse, and not every related predicate [Lewis] |
| Full Idea: Any theorist of universals as immanent had better hold a sparse theory; it is preposterous on its face that a thing has as many nonspatiotemporal parts as there are different predicates that it falls under, or different classes that it belongs to. | |
| From: David Lewis (Against Structural Universals [1986], 'Why believe') | |
| A reaction: I am firmly committed to sparse universal, and view the idea that properties are just predicates as the sort of nonsense that results from approaching philosophy too linguistically. |
| 15451 | I assume there could be natural properties that are not instantiated in our world [Lewis] |
| Full Idea: It is possible, I take it, that there might be simple natural properties different from any that instantiated within our world. | |
| From: David Lewis (Against Structural Universals [1986], 'Uninstantiated') | |
| A reaction: Interesting. Fine for Lewis, of course, for whom possibilities seem (to me) to be just logical possibilities. Even a scientific essentialist, though, must allow that different stuff might exist, which might have different intrinsic properties. |
| 15433 | Tropes are particular properties, which cannot recur, but can be exact duplicates [Lewis] |
| Full Idea: Tropes are supposed to be particularized properties: nonspatiotemporal parts of their instances which cannot occur repeatedly, but can be exact duplicates. | |
| From: David Lewis (Against Structural Universals [1986], 'Intro') | |
| A reaction: Russell's objection is that 'duplication' appears to be a non-trope universal. The account seems wrong for very close resemblance, which is accepted by everyone as being the same (e.g. in colour, for football shirts). |
| 15436 | Universals are meant to give an account of resemblance [Lewis] |
| Full Idea: Perhaps the main job of a theory of universals is to give an account of resemblance. | |
| From: David Lewis (Against Structural Universals [1986], 'Why believe') | |
| A reaction: This invites the quick reply, popular with some nominalists, of taking resemblance as primitive, and hence beyond explanation. |
| 15438 | We can add a primitive natural/unnatural distinction to class nominalism [Lewis] |
| Full Idea: To class nominalism we can add a primitive distinction between natural and unnatural classes. | |
| From: David Lewis (Against Structural Universals [1986], 'Why believe') | |
| A reaction: Lewis explores this elsewhere, but this looks like a very complex concept to play the role of a 'primitive'. Human conventions seem to be parts of nature. |
| 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. |
| 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? |
| 14283 | A conditional probability does not measure the probability of the truth of any proposition [Lewis, by Edgington] |
| Full Idea: Lewis was first to prove this remarkable result: there is no proposition A*B such that, in all probability distributions, p(A*B) = pA(B) [second A a subscript]. A conditional probability does not measure the probability of the truth of any proposition. | |
| From: report of David Lewis (Probabilities of Conditionals [1976]) by Dorothy Edgington - Conditionals (Stanf) 3.1 | |
| A reaction: The equation says the probability of the combination of A and B is not always the same as the probability of B given A. Bennett refers to this as 'The Equation' in the theory of conditionals. Edgington says a conditional is a supposition and a judgement. |
| 15450 | Maybe abstraction is just mereological subtraction [Lewis] |
| Full Idea: We could say that abstraction is just mereological subtraction of universals. | |
| From: David Lewis (Against Structural Universals [1986], 'Uninstantiated') | |
| A reaction: This only works, of course, for the theories that complex universals have simpler universals as 'parts'. This is just a passing surmise. I take it that abstraction only works for a thing whose unity survives the abstraction. |
| 15443 | Mathematicians abstract by equivalence classes, but that doesn't turn a many into one [Lewis] |
| Full Idea: When mathematicians abstract one thing from others, they take an equivalence class. ....But it is only superficially a one; underneath, a class are still many. | |
| From: David Lewis (Against Structural Universals [1986], 'The pictorial') | |
| A reaction: This is Frege's approach to abstraction, and it is helpful to have it spelled out that this is a mathematical technique, even when applied by Frege to obtaining 'direction' from classes of parallels. Too much philosophy borrows inappropriate techniques. |