74 ideas
| 13736 | Quinean metaphysics just lists the beings, which is a domain with no internal structure [Schaffer,J on Quine] |
| Full Idea: The Quinean task in metaphysics is to say what exists. What exists forms the domain of quantification. The domain is a set (or class, or plurality) - it has no internal structure. In other words, the Quinean task is to list the beings. | |
| From: comment on Willard Quine (works [1961]) by Jonathan Schaffer - On What Grounds What 1.1 | |
| A reaction: I really warm to this thesis. The Quinean version is what you get when you think that logic is the best tool for explicating metaphysics. Schaffer goes on to say that the only real aim for Quine is the cardinality of what exists! |
| 10987 | Three traditional names of rules are 'Simplification', 'Addition' and 'Disjunctive Syllogism' [Read] |
| Full Idea: Three traditional names for rules are 'Simplification' (P from 'P and Q'), 'Addition' ('P or Q' from P), and 'Disjunctive Syllogism' (Q from 'P or Q' and 'not-P'). | |
| From: Stephen Read (Thinking About Logic [1995], Ch.2) |
| 11004 | Necessity is provability in S4, and true in all worlds in S5 [Read] |
| Full Idea: In S4 necessity is said to be informal 'provability', and in S5 it is said to be 'true in every possible world'. | |
| From: Stephen Read (Thinking About Logic [1995], Ch.4) | |
| A reaction: It seems that the S4 version is proof-theoretic, and the S5 version is semantic. |
| 11018 | There are fuzzy predicates (and sets), and fuzzy quantifiers and modifiers [Read] |
| Full Idea: In fuzzy logic, besides fuzzy predicates, which define fuzzy sets, there are also fuzzy quantifiers (such as 'most' and 'few') and fuzzy modifiers (such as 'usually'). | |
| From: Stephen Read (Thinking About Logic [1995], Ch.7) |
| 11011 | Same say there are positive, negative and neuter free logics [Read] |
| Full Idea: It is normal to classify free logics into three sorts; positive free logics (some propositions with empty terms are true), negative free logics (they are false), and neuter free logics (they lack truth-value), though I find this unhelpful and superficial. | |
| From: Stephen Read (Thinking About Logic [1995], Ch.5) |
| 3302 | Set theory is full of Platonist metaphysics, so Quine aimed to keep it separate from logic [Quine, by Benardete,JA] |
| Full Idea: Quine has showed us how set theory - now recognised to be positively awash in Platonistic metaphysics - can and should be prevented from infecting logic proper. | |
| From: report of Willard Quine (works [1961]) by José A. Benardete - Metaphysics: the logical approach Intro |
| 10211 | Quine wants V = L for a cleaner theory, despite the scepticism of most theorists [Quine, by Shapiro] |
| Full Idea: Quine suggests that V = L be accepted in set theory because it makes for a cleaner theory, even though most set theorists are skeptical of V = L. | |
| From: report of Willard Quine (works [1961]) by Stewart Shapiro - Philosophy of Mathematics Ch.1 | |
| A reaction: Shapiro cites it as a case of a philosopher trying to make recommendations to mathematicians. Maddy supports Quine. |
| 11020 | Realisms like the full Comprehension Principle, that all good concepts determine sets [Read] |
| Full Idea: Hard-headed realism tends to embrace the full Comprehension Principle, that every well-defined concept determines a set. | |
| From: Stephen Read (Thinking About Logic [1995], Ch.8) | |
| A reaction: This sort of thing gets you into trouble with Russell's paradox (though that is presumably meant to be excluded somehow by 'well-defined'). There are lots of diluted Comprehension Principles. |
| 3336 | Two things can never entail three things [Quine, by Benardete,JA] |
| Full Idea: Two things can never entail three things. | |
| From: report of Willard Quine (works [1961]) by José A. Benardete - Metaphysics: the logical approach Ch.17 |
| 10986 | Not all validity is captured in first-order logic [Read] |
| Full Idea: We must recognise that first-order classical logic is inadequate to describe all valid consequences, that is, all cases in which it is impossible for the premisses to be true and the conclusion false. | |
| From: Stephen Read (Thinking About Logic [1995], Ch.2) | |
| A reaction: This is despite the fact that first-order logic is 'complete', in the sense that its own truths are all provable. |
| 10972 | The non-emptiness of the domain is characteristic of classical logic [Read] |
| Full Idea: The non-emptiness of the domain is characteristic of classical logic. | |
| From: Stephen Read (Thinking About Logic [1995], Ch.2) |
| 11024 | Semantics must precede proof in higher-order logics, since they are incomplete [Read] |
| Full Idea: For the realist, study of semantic structures comes before study of proofs. In higher-order logic is has to, for the logics are incomplete. | |
| From: Stephen Read (Thinking About Logic [1995], Ch.9) | |
| A reaction: This seems to be an important general observation about any incomplete system, such as Peano arithmetic. You may dream the old rationalist dream of starting from the beginning and proving everything, but you can't. Start with truth and meaning. |
| 10985 | We should exclude second-order logic, precisely because it captures arithmetic [Read] |
| Full Idea: Those who believe mathematics goes beyond logic use that fact to argue that classical logic is right to exclude second-order logic. | |
| From: Stephen Read (Thinking About Logic [1995], Ch.2) |
| 10970 | A theory of logical consequence is a conceptual analysis, and a set of validity techniques [Read] |
| Full Idea: A theory of logical consequence, while requiring a conceptual analysis of consequence, also searches for a set of techniques to determine the validity of particular arguments. | |
| From: Stephen Read (Thinking About Logic [1995], Ch.2) |
| 10984 | Logical consequence isn't just a matter of form; it depends on connections like round-square [Read] |
| Full Idea: If classical logic insists that logical consequence is just a matter of the form, we fail to include as valid consequences those inferences whose correctness depends on the connections between non-logical terms (such as 'round' and 'square'). | |
| From: Stephen Read (Thinking About Logic [1995], Ch.2) | |
| A reaction: He suggests that an inference such as 'round, so not square' should be labelled as 'materially valid'. |
| 10973 | A theory is logically closed, which means infinite premisses [Read] |
| Full Idea: A 'theory' is any logically closed set of propositions, ..and since any proposition has infinitely many consequences, including all the logical truths, so that theories have infinitely many premisses. | |
| From: Stephen Read (Thinking About Logic [1995], Ch.2) | |
| A reaction: Read is introducing this as the essential preliminary to an account of the Compactness Theorem, which relates these infinite premisses to the finite. |
| 8453 | If we had to name objects to make existence claims, we couldn't discuss all the real numbers [Quine] |
| Full Idea: Since one wants to say that real numbers exist and yet one cannot name each of them, it is not unreasonable to relinquish the connection between naming an object and making an existence claim about it. | |
| From: Willard Quine (works [1961]), quoted by Alex Orenstein - W.V. Quine Ch.2 | |
| A reaction: One could say that same about people, such as 'the most recent citizen of Brazil'. Some sort of successful reference seems to be needed, such as 'the next prime beyond the biggest so far found'. Depends what your predicate is going to be. |
| 11007 | Quantifiers are second-order predicates [Read] |
| Full Idea: Quantifiers are second-order predicates. | |
| From: Stephen Read (Thinking About Logic [1995], Ch.5) | |
| A reaction: [He calls this 'Frege's insight'] They seem to be second-order in Tarski's sense, that they are part of a metalanguage about the sentence, rather than being a part of the sentence. |
| 10311 | No sense can be made of quantification into opaque contexts [Quine, by Hale] |
| Full Idea: Quine says that no good sense can be made of quantification into opaque contexts. | |
| From: report of Willard Quine (works [1961]) by Bob Hale - Abstract Objects Ch.2 | |
| A reaction: This is because poor old Quine was trapped in a world of language, and had lost touch with reality. I can quantify over the things you are thinking about, as long as you are thinking about things that can be quantified over. |
| 10538 | Finite quantification can be eliminated in favour of disjunction and conjunction [Quine, by Dummett] |
| Full Idea: Quine even asserts that where we have no infinite domains, quantification can be eliminated in favour of finite disjunction and conjunction. | |
| From: report of Willard Quine (works [1961]) by Michael Dummett - Frege Philosophy of Language (2nd ed) Ch.14 | |
| A reaction: Thus ∃x is expressed as 'this or this or this...', and ∀ is expressed as 'this and this and this...' Dummett raises an eyebrow, but it sounds OK to me. |
| 10793 | Quine thought substitutional quantification confused use and mention, but then saw its nominalist appeal [Quine, by Marcus (Barcan)] |
| Full Idea: Quine at first regarded substitutional quantification as incoherent, behind which there lurked use-mention confusions, but has over the years, given his nominalist dispositions, come to notice its appeal. | |
| From: report of Willard Quine (works [1961]) by Ruth Barcan Marcus - Nominalism and Substitutional Quantifiers p.166 |
| 10978 | In second-order logic the higher-order variables range over all the properties of the objects [Read] |
| Full Idea: The defining factor of second-order logic is that, while the domain of its individual variables may be arbitrary, the range of the first-order variables is all the properties of the objects in its domain (or, thinking extensionally, of the sets objects). | |
| From: Stephen Read (Thinking About Logic [1995], Ch.2) | |
| A reaction: The key point is that the domain is 'all' of the properties. How many properties does an object have. You need to decide whether you believe in sparse or abundant properties (I vote for very sparse indeed). |
| 10971 | A logical truth is the conclusion of a valid inference with no premisses [Read] |
| Full Idea: Logical truth is a degenerate, or extreme, case of consequence. A logical truth is the conclusion of a valid inference with no premisses, or a proposition in the premisses of an argument which is unnecessary or may be suppressed. | |
| From: Stephen Read (Thinking About Logic [1995], Ch.2) |
| 10988 | Any first-order theory of sets is inadequate [Read] |
| Full Idea: Any first-order theory of sets is inadequate because of the Löwenheim-Skolem-Tarski property, and the consequent Skolem paradox. | |
| From: Stephen Read (Thinking About Logic [1995], Ch.2) | |
| A reaction: The limitation is in giving an account of infinities. |
| 10974 | Compactness is when any consequence of infinite propositions is the consequence of a finite subset [Read] |
| Full Idea: Classical logical consequence is compact, which means that any consequence of an infinite set of propositions (such as a theory) is a consequence of some finite subset of them. | |
| From: Stephen Read (Thinking About Logic [1995], Ch.2) |
| 10975 | Compactness does not deny that an inference can have infinitely many premisses [Read] |
| Full Idea: Compactness does not deny that an inference can have infinitely many premisses. It can; but classically, it is valid if and only if the conclusion follows from a finite subset of them. | |
| From: Stephen Read (Thinking About Logic [1995], Ch.2) |
| 10977 | Compactness blocks the proof of 'for every n, A(n)' (as the proof would be infinite) [Read] |
| Full Idea: Compact consequence undergenerates - there are intuitively valid consequences which it marks as invalid, such as the ω-rule, that if A holds of the natural numbers, then 'for every n, A(n)', but the proof of that would be infinite, for each number. | |
| From: Stephen Read (Thinking About Logic [1995], Ch.2) |
| 10976 | Compactness makes consequence manageable, but restricts expressive power [Read] |
| Full Idea: Compactness is a virtue - it makes the consequence relation more manageable; but it is also a limitation - it limits the expressive power of the logic. | |
| From: Stephen Read (Thinking About Logic [1995], Ch.2) | |
| A reaction: The major limitation is that wholly infinite proofs are not permitted, as in Idea 10977. |
| 11014 | Self-reference paradoxes seem to arise only when falsity is involved [Read] |
| Full Idea: It cannot be self-reference alone that is at fault. Rather, what seems to cause the problems in the paradoxes is the combination of self-reference with falsity. | |
| From: Stephen Read (Thinking About Logic [1995], Ch.6) |
| 11025 | Infinite cuts and successors seems to suggest an actual infinity there waiting for us [Read] |
| Full Idea: Every potential infinity seems to suggest an actual infinity - e.g. generating successors suggests they are really all there already; cutting the line suggests that the point where the cut is made is already in place. | |
| From: Stephen Read (Thinking About Logic [1995], Ch.8) | |
| A reaction: Finding a new gambit in chess suggests it was there waiting for us, but we obviously invented chess. Daft. |
| 10979 | Although second-order arithmetic is incomplete, it can fully model normal arithmetic [Read] |
| Full Idea: Second-order arithmetic is categorical - indeed, there is a single formula of second-order logic whose only model is the standard model ω, consisting of just the natural numbers, with all of arithmetic following. It is nevertheless incomplete. | |
| From: Stephen Read (Thinking About Logic [1995], Ch.2) | |
| A reaction: This is the main reason why second-order logic has a big fan club, despite the logic being incomplete (as well as the arithmetic). |
| 10980 | Second-order arithmetic covers all properties, ensuring categoricity [Read] |
| Full Idea: Second-order arithmetic can rule out the non-standard models (with non-standard numbers). Its induction axiom crucially refers to 'any' property, which gives the needed categoricity for the models. | |
| From: Stephen Read (Thinking About Logic [1995], Ch.2) |
| 10997 | Von Neumann numbers are helpful, but don't correctly describe numbers [Read] |
| Full Idea: The Von Neumann numbers have a structural isomorphism to the natural numbers - each number is the set of all its predecessors, so 2 is the set of 0 and 1. This helps proofs, but is unacceptable. 2 is not a set with two members, or a member of 3. | |
| From: Stephen Read (Thinking About Logic [1995], Ch.4) |
| 8466 | For Quine, intuitionist ontology is inadequate for classical mathematics [Quine, by Orenstein] |
| Full Idea: Quine feels that the intuitionist's ontology of abstract objects is too slight to serve the needs of classical mathematics. | |
| From: report of Willard Quine (works [1961]) by Alex Orenstein - W.V. Quine Ch.3 | |
| A reaction: Quine, who devoted his life to the application of Ockham's Razor, decided that sets were an essential part of the ontological baggage (which made him, according to Orenstein, a 'reluctant Platonist'). Dummett defends intuitionism. |
| 8467 | Intuitionists only admit numbers properly constructed, but classical maths covers all reals in a 'limit' [Quine, by Orenstein] |
| Full Idea: Intuitionists will not admit any numbers which are not properly constructed out of rational numbers, ...but classical mathematics appeals to the real numbers (a non-denumerable totality) in notions such as that of a limit | |
| From: report of Willard Quine (works [1961]) by Alex Orenstein - W.V. Quine Ch.3 | |
| A reaction: (See Idea 8454 for the categories of numbers). This is a problem for Dummett. |
| 11016 | Would a language without vagueness be usable at all? [Read] |
| Full Idea: We must ask whether a language without vagueness would be usable at all. | |
| From: Stephen Read (Thinking About Logic [1995], Ch.7) | |
| A reaction: Popper makes a similar remark somewhere, with which I heartily agreed. This is the idea of 'spreading the word' over the world, which seems the right way of understanding it. |
| 11019 | Supervaluations say there is a cut-off somewhere, but at no particular place [Read] |
| Full Idea: The supervaluation approach to vagueness is to construe vague predicates not as ones with fuzzy borderlines and no cut-off, but as having a cut-off somewhere, but in no particular place. | |
| From: Stephen Read (Thinking About Logic [1995], Ch.7) | |
| A reaction: Presumably you narrow down the gap by supervaluation, then split the difference to get a definite value. |
| 11012 | A 'supervaluation' gives a proposition consistent truth-value for classical assignments [Read] |
| Full Idea: A 'supervaluation' says a proposition is true if it is true in all classical extensions of the original partial valuation. Thus 'A or not-A' has no valuation for an empty name, but if 'extended' to make A true or not-true, not-A always has opposite value. | |
| From: Stephen Read (Thinking About Logic [1995], Ch.5) |
| 11013 | Identities and the Indiscernibility of Identicals don't work with supervaluations [Read] |
| Full Idea: In supervaluations, the Law of Identity has no value for empty names, and remains so if extended. The Indiscernibility of Identicals also fails if extending it for non-denoting terms, where Fa comes out true and Fb false. | |
| From: Stephen Read (Thinking About Logic [1995], Ch.5) |
| 10667 | A logically perfect language could express all truths, so all truths must be logically expressible [Quine, by Hossack] |
| Full Idea: Quine's test of ontological commitment says that anything that can be said truly at all must be capable of being said in a logically perfect language, so there must be a paraphrase of every truth into the language of logic. | |
| From: report of Willard Quine (works [1961]) by Keith Hossack - Plurals and Complexes 2 | |
| A reaction: A very nice statement of the Quinean view, much more persuasive than other statements I have encountered. I am suddenly almost converted to a doctrine I have hitherto despised. Isn't philosophy wonderful? |
| 16021 | Quine says we can expand predicates easily (ideology), but not names (ontology) [Quine, by Noonan] |
| Full Idea: The highly intuitive methodological programme enunciated by Quine says that as our knowledge expands we should unhesitatingly expand our ideology, our stock of predicables, but should be much more wary about ontology, the name variables. | |
| From: report of Willard Quine (works [1961]) by Harold Noonan - Identity §3 | |
| A reaction: I suddenly embrace this as a crucial truth. This distinction allows you to expand on truths without expanding on reality. I would add that it is also crucial to distinguish properties from predicates. A new predicate isn't a new property. |
| 3325 | For Quine everything exists theoretically, as reference, predication and quantification [Quine, by Benardete,JA] |
| Full Idea: Theoretical entities (which is everything, according to Quine) are postulated by us in a threefold fashion as an object (1) to which we refer, (2) of which we predicate, and (3) over which we quantify. | |
| From: report of Willard Quine (works [1961]) by José A. Benardete - Metaphysics: the logical approach Ch.12 |
| 8534 | Quine says the predicate of a true statement has no ontological implications [Quine, by Armstrong] |
| Full Idea: Quine's doctrine is that the predicate of a true statement carries no ontological implications. | |
| From: report of Willard Quine (works [1961]) by David M. Armstrong - Properties §1 | |
| A reaction: Quine is ontologically committed to the subject of the statement (an object). The predicate seems to be an inseparable part of that object. Quine is, of course, a holist, so ontological commitment isn't judged in single statements. |
| 10295 | Quine suggests that properties can be replaced with extensional entities like sets [Quine, by Shapiro] |
| Full Idea: Quine doubts the existence of properties, and, trying to be helpful, suggests that variables ranging over properties be replaced with variables ranging over respectable extensional entities like sets, so we can 'identify' a property with a singleton set. | |
| From: report of Willard Quine (works [1961]) by Stewart Shapiro - Higher-Order Logic 2.1 | |
| A reaction: This strikes me as a classic modern heresy, a slippery slope that loses all grip on what a property is, replacing it with entities that mean nothing, but make the logic work. |
| 3322 | Quine says that if second-order logic is to quantify over properties, that can be done in first-order predicate logic [Quine, by Benardete,JA] |
| Full Idea: Quine assures us that if the specific mission of second-order logic is quantifying over properties, the task can readily be performed by first-order predicate logic, as in (Ex) x is a property, and (y) y has x. | |
| From: report of Willard Quine (works [1961]) by José A. Benardete - Metaphysics: the logical approach Ch.10 |
| 6078 | Quine brought classes into semantics to get rid of properties [Quine, by McGinn] |
| Full Idea: Quine brought classes into semantics in order to oust properties. | |
| From: report of Willard Quine (works [1961]) by Colin McGinn - Logical Properties Ch.3 | |
| A reaction: Quine's view has always struck me as odd, as I don't see how you can decide what set something belongs to if you haven't already decided its properties. But then I take it that nature informs you of most properties, and set membership is not arbitrary. |
| 8479 | Don't analyse 'red is a colour' as involving properties. Say 'all red things are coloured things' [Quine, by Orenstein] |
| Full Idea: Quine proposes that 'red is a colour' does not require analysis, such as 'there is an x which is the property of being red and it is a colour' which needs an ontology of properties. We can just say that all red things are coloured things. | |
| From: report of Willard Quine (works [1961]) by Alex Orenstein - W.V. Quine Ch.6 | |
| A reaction: The question of the ontology of properties is here approached, in twentieth century style, as the question 'what is the logical form of property attribution sentences?' Quine's version deals in sets of prior objects, rather than abstract entities. |
| 3751 | Universals are acceptable if they are needed to make an accepted theory true [Quine, by Jacquette] |
| Full Idea: Abstract entities (universals) are admitted to an ontology by Quine's criterion if they must be supposed to exist (or subsist) in order to make the propositions of an accepted theory true. | |
| From: report of Willard Quine (works [1961]) by Dale Jacquette - Abstract Entity p.3 |
| 7970 | Quine is committed to sets, but is more a Class Nominalist than a Platonist [Quine, by Macdonald,C] |
| Full Idea: Armstrong dubs Quine an 'Ostrich Nominalist' (what problem??), but Quine calls himself a Platonist, because he is committed to classes or sets as well as particulars. He is not an extreme nominalist, and might best be called a Class Nominalist. | |
| From: report of Willard Quine (works [1961], Ch.6 n15) by Cynthia Macdonald - Varieties of Things | |
| A reaction: For someone as ontologically austere as Quine to show 'commitment' to sets deserves some recognition. If he wants to be a Platonist, I say that's fine. What on earth is a set, apart from its members? |
| 15783 | Definite descriptions can't unambiguously pick out an object which doesn't exist [Lycan on Quine] |
| Full Idea: Meinong characteristically refers to his Objects using definite descriptions, such as 'the golden mountain'. But on his view there are many golden mountains, with different features. How can 'the golden mountain' then succeed in denoting a single Object? | |
| From: comment on Willard Quine (works [1961]) by William Lycan - The Trouble with Possible Worlds 01 | |
| A reaction: Use of definite descriptions doesn't seem obligatory in this situation. 'Think of a golden mountain' - 'which one?' - 'never mind which one!'. |
| 10995 | A haecceity is a set of individual properties, essential to each thing [Read] |
| Full Idea: The haecceitist (a neologism coined by Duns Scotus, pronounced 'hex-ee-it-ist', meaning literally 'thisness') believes that each thing has an individual essence, a set of properties which are essential to it. | |
| From: Stephen Read (Thinking About Logic [1995], Ch.4) | |
| A reaction: This seems to be a difference of opinion over whether a haecceity is a set of essential properties, or a bare particular. The key point is that it is unique to each entity. |
| 11001 | Equating necessity with truth in every possible world is the S5 conception of necessity [Read] |
| Full Idea: The equation of 'necessity' with 'true in every possible world' is known as the S5 conception, corresponding to the strongest of C.I.Lewis's five modal systems. | |
| From: Stephen Read (Thinking About Logic [1995], Ch.4) | |
| A reaction: Are the worlds naturally, or metaphysically, or logically possible? |
| 15782 | Quine wants identity and individuation-conditions for possibilia [Quine, by Lycan] |
| Full Idea: Quine notoriously demands identity and individuation-conditions for mere possibilia. | |
| From: report of Willard Quine (works [1961]) by William Lycan - The Trouble with Possible Worlds 01 | |
| A reaction: Demanding individuation before speaking of anything strikes me as dubious. 'Whoever did this should own up'. 'There must be something we can do'. Obviously you need some idea of what you are talking about - but not much. |
| 10992 | The point of conditionals is to show that one will accept modus ponens [Read] |
| Full Idea: The point of conditionals is to show that one will accept modus ponens. | |
| From: Stephen Read (Thinking About Logic [1995], Ch.3) | |
| A reaction: [He attributes this idea to Frank Jackson] This makes the point, against Grice, that the implication of conditionals is not conversational but a matter of logical convention. See Idea 21396 for a very different view. |
| 10989 | The standard view of conditionals is that they are truth-functional [Read] |
| Full Idea: The standard view of conditionals is that they are truth-functional, that is, that their truth-values are determined by the truth-values of their constituents. | |
| From: Stephen Read (Thinking About Logic [1995], Ch.3) |
| 11017 | Some people even claim that conditionals do not express propositions [Read] |
| Full Idea: Some people even claim that conditionals do not express propositions. | |
| From: Stephen Read (Thinking About Logic [1995], Ch.7) | |
| A reaction: See Idea 14283, where this appears to have been 'proved' by Lewis, and is not just a view held by some people. |
| 2796 | For Quine the only way to know a necessity is empirically [Quine, by Dancy,J] |
| Full Idea: Quine argues that no necessity can be known other than empirically. | |
| From: report of Willard Quine (works [1961]) by Jonathan Dancy - Intro to Contemporary Epistemology 14.6 |
| 10983 | Knowledge of possible worlds is not causal, but is an ontology entailed by semantics [Read] |
| Full Idea: The modal Platonist denies that knowledge always depends on a causal relation. The reality of possible worlds is an ontological requirement, to secure the truth-values of modal propositions. | |
| From: Stephen Read (Thinking About Logic [1995], Ch.2) | |
| A reaction: [Reply to Idea 10982] This seems to be a case of deriving your metaphyics from your semantics, of which David Lewis seems to be guilty, and which strikes me as misguided. |
| 10982 | How can modal Platonists know the truth of a modal proposition? [Read] |
| Full Idea: If modal Platonism was true, how could we ever know the truth of a modal proposition? | |
| From: Stephen Read (Thinking About Logic [1995], Ch.2) | |
| A reaction: I take this to be very important. Our knowledge of modal truths must depend on our knowledge of the actual world. The best answer seems to involve reference to the 'powers' of the actual world. A reply is in Idea 10983. |
| 10996 | Actualism is reductionist (to parts of actuality), or moderate realist (accepting real abstractions) [Read] |
| Full Idea: There are two main forms of actualism: reductionism, which seeks to construct possible worlds out of some more mundane material; and moderate realism, in which the actual concrete world is contrasted with abstract, but none the less real, possible worlds. | |
| From: Stephen Read (Thinking About Logic [1995], Ch.4) | |
| A reaction: I am a reductionist, as I do not take abstractions to be 'real' (precisely because they have been 'abstracted' from the things that are real). I think I will call myself a 'scientific modalist' - we build worlds from possibilities, discovered by science. |
| 10981 | A possible world is a determination of the truth-values of all propositions of a domain [Read] |
| Full Idea: A possible world is a complete determination of the truth-values of all propositions over a certain domain. | |
| From: Stephen Read (Thinking About Logic [1995], Ch.2) | |
| A reaction: Even if the domain is very small? Even if the world fitted the logic nicely, but was naturally impossible? |
| 11000 | If worlds are concrete, objects can't be present in more than one, and can only have counterparts [Read] |
| Full Idea: If each possible world constitutes a concrete reality, then no object can be present in more than one world - objects may have 'counterparts', but cannot be identical with them. | |
| From: Stephen Read (Thinking About Logic [1995], Ch.4) | |
| A reaction: This explains clearly why in Lewis's modal realist scheme he needs counterparts instead of rigid designation. Sounds like a slippery slope. If you say 'Humphrey might have won the election', who are you talking about? |
| 8450 | Quine's empiricism is based on whole theoretical systems, not on single mental events [Quine, by Orenstein] |
| Full Idea: Traditional empiricism takes impressions, ideas or sense data as the basic unit of empirical thought, but Quine takes account of the theoretical as well as the observational; the unit of empirical significance is whole systems of belief. | |
| From: report of Willard Quine (works [1961]) by Alex Orenstein - W.V. Quine Ch.1 | |
| A reaction: This invites either the question of what components make up the whole systems, or (alternatively) what sort of mental events decide to accept a system as a whole. Should Quine revert either to traditional empiricism, or to rationalism? |
| 3868 | To proclaim cultural relativism is to thereby rise above it [Quine, by Newton-Smith] |
| Full Idea: Truth, says the cultural relativist, is culture-bound. But if it were, then he, within his own culture, ought to see his own culture-bound truth as absolute. He cannot proclaim cultural relativism without rising above it. | |
| From: report of Willard Quine (works [1961]) by W.H. Newton-Smith - The Rationality of Science VII.10 |
| 4713 | For Quine, theories are instruments used to make predictions about observations [Quine, by O'Grady] |
| Full Idea: Quine's epistemological position is instrumentalist. Our theories are instruments we use to make predictions about observations. | |
| From: report of Willard Quine (works [1961]) by Paul O'Grady - Relativism Ch.3 | |
| A reaction: This is the pragmatist in Quine. It fits the evolutionary view to think that the bottom line is prediction. My theory about the Pelopponesian War seems an exception. |
| 10998 | The mind abstracts ways things might be, which are nonetheless real [Read] |
| Full Idea: Ways things might be are real, but only when abstracted from the actual way things are. They are brought out and distinguished by the mind, by abstraction, but are not dependent on mind for their existence. | |
| From: Stephen Read (Thinking About Logic [1995], Ch.4) | |
| A reaction: To me this just flatly contradicts itself. The idea that the mind can 'bring something out' by its operations, with the result being then accepted as part of reality is nonsense on stilts. What is real is the powers that make the possibilities. |
| 4712 | Quine says there is no matter of fact about reference - it is 'inscrutable' [Quine, by O'Grady] |
| Full Idea: Quine holds the doctrine of the 'inscrutability of reference', which means there is no fact of the matter about reference. | |
| From: report of Willard Quine (works [1961]) by Paul O'Grady - Relativism Ch.3 | |
| A reaction: Presumably reference depends on conventions like pointing, or the functioning of words like "that", or the ambiguities of descriptions. If you can't define it, it doesn't exist? I don't believe him. |
| 11005 | Negative existentials with compositionality make the whole sentence meaningless [Read] |
| Full Idea: A problem with compositionality is negative existential propositions. If some of the terms of the proposition are empty, and don't refer, then compositionality implies that the whole will lack meaning too. | |
| From: Stephen Read (Thinking About Logic [1995], Ch.5) | |
| A reaction: I don't agree. I don't see why compositionality implies holism about sentence-meaning. If I say 'that circular square is a psychopath', you understand the predication, despite being puzzled by the singular term. |
| 10966 | A proposition objectifies what a sentence says, as indicative, with secure references [Read] |
| Full Idea: A proposition makes an object out of what is said or expressed by the utterance of a certain sort of sentence, namely, one in the indicative mood which makes sense and doesn't fail in its references. It can then be an object of thought and belief. | |
| From: Stephen Read (Thinking About Logic [1995], Ch.1) | |
| A reaction: Nice, but two objections: I take it to be crucial to propositions that they eliminate ambiguities, and I take it that animals are capable of forming propositions. Read seems to regard them as fictions, but I take them to be brain events. |
| 7330 | The principle of charity only applies to the logical constants [Quine, by Miller,A] |
| Full Idea: Quine takes to the principle of charity to apply only to the translation of the logical constants. | |
| From: report of Willard Quine (works [1961]) by Alexander Miller - Philosophy of Language 8.7 | |
| A reaction: Given how weird some people's view of the world seems to be, this very cautious approach has an interesting rival appeal to Davidson't much more charitable view, that people mostly speak truth. It depends whether you are discussing lunch or the gods. |
| 21093 | Friendship without community spirit misses out on the main part of virtue [Hume] |
| Full Idea: A man who is only susceptible of friendship, without public spirit or a regard to the community, is deficient in the most material part of virtue. | |
| From: David Hume (That Politics may be reduced to a Science [1750], p.21) | |
| A reaction: I think this is aimed at the epicureans. If the highest virtues are focused on one's friends that can easily lead to injustice, because it can tolerate prejudice against people who are very unlike one's friends. |
| 21091 | It would be absurd if even a free constitution did not impose restraints, for the public good [Hume] |
| Full Idea: A republican and free form of government would be an obvious absurdity, if the particular checks and controls, provided by the constitution, had really no influence, and made it not the interest, even of bad men, to act for the public good. | |
| From: David Hume (That Politics may be reduced to a Science [1750], p.14) | |
| A reaction: Presumably if you attain absolute power you can write any old constitution you like (Clause 1: the presidency is for life). But there does seem much point in doing it - unless it is to facilitate the use of the law for persecutions. |
| 21092 | Nobility either share in the power of the whole, or they compose the power of the whole [Hume] |
| Full Idea: A nobility may possess power in two different ways. Either every nobleman shares the power as part of the whole body, or the whole body enjoys the power as composed of parts, which each have a distinct power and authority. | |
| From: David Hume (That Politics may be reduced to a Science [1750], p.15) | |
| A reaction: He says the first type is found in Venice, and is preferable to the second type, which is found in Poland. Presumably in the shared version there is some restraint on depraved nobles. The danger is each noble being an autocrat. |
| 17862 | Essence gives an illusion of understanding [Quine, by Almog] |
| Full Idea: Essence engenders a mere illusion of understanding | |
| From: report of Willard Quine (works [1961]) by Joseph Almog - Nature Without Essence Intro | |
| A reaction: [Almog quotes Quine, but doesn't give a reference] This is roughly the same as Popper's criticism of essentialism. |