43 ideas
| 10308 | Questions about objects are questions about certain non-vacuous singular terms [Hale] |
| Full Idea: I understand questions about the Fregean notion of an object to be inseparable from questions in the philosophy of language - questions of the existence of objects are tantamount to questions about non-vacuous singular terms of a certain kind. | |
| From: Bob Hale (Abstract Objects [1987], Ch.1) | |
| A reaction: This view hovers somewhere between Quine and J.L. Austin, and Dummett is its originator. I am instinctively deeply opposed to the identification of metaphysics with semantics. |
| 10314 | An expression is a genuine singular term if it resists elimination by paraphrase [Hale] |
| Full Idea: An expression ... should be reckoned a genuine singular term only if it resists elimination by paraphrase. | |
| From: Bob Hale (Abstract Objects [1987], Ch.2.II) | |
| A reaction: This strikes me as extraordinarily optimistic. It will be relative to a language, and the resources of a given speaker, and seems open to the invention of new expressions to do the job (e.g. an equivalent adjective for every noun in the dictionary). |
| 10779 | A comprehension axiom is 'predicative' if the formula has no bound second-order variables [Linnebo] |
| Full Idea: If φ contains no bound second-order variables, the corresponding comprehension axiom is said to be 'predicative'; otherwise it is 'impredicative'. | |
| From: Øystein Linnebo (Plural Quantification Exposed [2003], §1) | |
| A reaction: ['Predicative' roughly means that a new predicate is created, and 'impredicative' means that it just uses existing predicates] |
| 10781 | A 'pure logic' must be ontologically innocent, universal, and without presuppositions [Linnebo] |
| Full Idea: I offer these three claims as a partial analysis of 'pure logic': ontological innocence (no new entities are introduced), universal applicability (to any realm of discourse), and cognitive primacy (no extra-logical ideas are presupposed). | |
| From: Øystein Linnebo (Plural Quantification Exposed [2003], §1) |
| 8729 | Intuitionists deny excluded middle, because it is committed to transcendent truth or objects [Shapiro] |
| Full Idea: Intuitionists in mathematics deny excluded middle, because it is symptomatic of faith in the transcendent existence of mathematical objects and/or the truth of mathematical statements. | |
| From: Stewart Shapiro (Thinking About Mathematics [2000], 1.2) | |
| A reaction: There are other problems with excluded middle, such as vagueness, but on the whole I, as a card-carrying 'realist', am committed to the law of excluded middle. |
| 10316 | We should decide whether singular terms are genuine by their usage [Hale] |
| Full Idea: The criteria for a genuine singular term should pick out not the singular terms themselves but their uses, since they may be genuine in one context and not another. | |
| From: Bob Hale (Abstract Objects [1987], Ch.2.II) | |
| A reaction: [rephrased] This will certainly meet problems with vagueness (e.g. as the reference of a singular term is gradually clarified). |
| 10312 | Often the same singular term does not ensure reliable inference [Hale] |
| Full Idea: In 'the whale is increasingly scarce' and 'the whale is much improved today' (our pet whale), we cannot infer that there is something that is much improved and increasingly scarce, so this singular term fails Dummett's criterion based on inference. | |
| From: Bob Hale (Abstract Objects [1987], Ch.2) | |
| A reaction: [much rephrased] This is not just a problem for a few cunningly selected examples. With contortions almost any singular term can be undermined in this way. Singular terms are simply not a useful guide to the existence of abstracta. |
| 10313 | Plenty of clear examples have singular terms with no ontological commitment [Hale] |
| Full Idea: Some examples where a definite singular noun phrase is not 'genuine' (giving ontological commitment): 'left us in the lurch'; 'for my mother's sake'; 'given the sack'; 'in the nick of time', 'the whereabouts of the PM', 'the identity of the murderer'. | |
| From: Bob Hale (Abstract Objects [1987], Ch.2.II) | |
| A reaction: These are not just freakish examples. If I 'go on a journey', that doesn't involve extra entities called 'journeys', just because the meaning is clearer and a more commonplace part of the language. |
| 10322 | If singular terms can't be language-neutral, then we face a relativity about their objects [Hale] |
| Full Idea: If we lack any general, language-neutral characterization of singular terms, must not a parallel linguistic relativity infect the objects which are to be thought of as their non-linguistic correlates? | |
| From: Bob Hale (Abstract Objects [1987], Ch.2.III) | |
| A reaction: Hale thinks he can answer this, but I would have thought that this problem dooms the linguistic approach from the start. There needs to be more imagination about how very different a language could be, while still qualifying as a language. |
| 10778 | Can second-order logic be ontologically first-order, with all the benefits of second-order? [Linnebo] |
| Full Idea: According to its supporters, second-order logic allow us to pay the ontological price of a mere first-order theory and get the corresponding monadic second-order theory for free. | |
| From: Øystein Linnebo (Plural Quantification Exposed [2003], §0) |
| 10783 | Plural quantification depends too heavily on combinatorial and set-theoretic considerations [Linnebo] |
| Full Idea: If my arguments are correct, the theory of plural quantification has no right to the title 'logic'. ...The impredicative plural comprehension axioms depend too heavily on combinatorial and set-theoretic considerations. | |
| From: Øystein Linnebo (Plural Quantification Exposed [2003], §4) |
| 8763 | The number 3 is presumably identical as a natural, an integer, a rational, a real, and complex [Shapiro] |
| Full Idea: It is surely wise to identify the positions in the natural numbers structure with their counterparts in the integer, rational, real and complex number structures. | |
| From: Stewart Shapiro (Thinking About Mathematics [2000], 10.2) | |
| A reaction: The point is that this might be denied, since 3, 3/1, 3.00.., and -3*i^2 are all arrived at by different methods of construction. Natural 3 has a predecessor, but real 3 doesn't. I agree, intuitively, with Shapiro. Russell (1919) disagreed. |
| 18249 | Cauchy gave a formal definition of a converging sequence. [Shapiro] |
| Full Idea: A sequence a1,a2,... of rational numbers is 'Cauchy' if for each rational number ε>0 there is a natural number N such that for all natural numbers m, n, if m>N and n>N then -ε < am - an < ε. | |
| From: Stewart Shapiro (Thinking About Mathematics [2000], 7.2 n4) | |
| A reaction: The sequence is 'Cauchy' if N exists. |
| 8764 | Categories are the best foundation for mathematics [Shapiro] |
| Full Idea: There is a dedicated contingent who hold that the category of 'categories' is the proper foundation for mathematics. | |
| From: Stewart Shapiro (Thinking About Mathematics [2000], 10.3 n7) | |
| A reaction: He cites Lawvere (1966) and McLarty (1993), the latter presenting the view as a form of structuralism. I would say that the concept of a category will need further explication, and probably reduce to either sets or relations or properties. |
| 8762 | Two definitions of 3 in terms of sets disagree over whether 1 is a member of 3 [Shapiro] |
| Full Idea: Zermelo said that for each number n, its successor is the singleton of n, so 3 is {{{null}}}, and 1 is not a member of 3. Von Neumann said each number n is the set of numbers less than n, so 3 is {null,{null},{null,{null}}}, and 1 is a member of 3. | |
| From: Stewart Shapiro (Thinking About Mathematics [2000], 10.2) | |
| A reaction: See Idea 645 - Zermelo could save Plato from the criticisms of Aristotle! These two accounts are cited by opponents of the set-theoretical account of numbers, because it seems impossible to arbitrate between them. |
| 8760 | Numbers do not exist independently; the essence of a number is its relations to other numbers [Shapiro] |
| Full Idea: The structuralist vigorously rejects any sort of ontological independence among the natural numbers; the essence of a natural number is its relations to other natural numbers. | |
| From: Stewart Shapiro (Thinking About Mathematics [2000], 10.1) | |
| A reaction: This seems to place the emphasis on ordinals (what order?) rather than on cardinality (how many?). I am strongly inclined to think that this is the correct view, though you can't really have relations if there is nothing to relate. |
| 8761 | A 'system' is related objects; a 'pattern' or 'structure' abstracts the pure relations from them [Shapiro] |
| Full Idea: A 'system' is a collection of objects with certain relations among them; a 'pattern' or 'structure' is the abstract form of a system, highlighting the interrelationships and ignoring any features they do not affect how they relate to other objects. | |
| From: Stewart Shapiro (Thinking About Mathematics [2000], 10.1) | |
| A reaction: Note that 'ignoring' features is a psychological account of abstraction, which (thanks to Frege and Geach) is supposed to be taboo - but which I suspect is actually indispensable in any proper account of thought and concepts. |
| 8744 | Logicism seems to be a non-starter if (as is widely held) logic has no ontology of its own [Shapiro] |
| Full Idea: The thesis that principles of arithmetic are derivable from the laws of logic runs against a now common view that logic itself has no ontology. There are no particular logical objects. From this perspective logicism is a non-starter. | |
| From: Stewart Shapiro (Thinking About Mathematics [2000], 5.1) | |
| A reaction: This criticism strikes me as utterly devastating. There are two routes to go: prove that logic does have an ontology of objects (what would they be?), or - better - deny that arithmetic contains any 'objects'. Or give up logicism. |
| 8749 | Term Formalism says mathematics is just about symbols - but real numbers have no names [Shapiro] |
| Full Idea: Term Formalism is the view that mathematics is just about characters or symbols - the systems of numerals and other linguistic forms. ...This will cover integers and rational numbers, but what are real numbers supposed to be, if they lack names? | |
| From: Stewart Shapiro (Thinking About Mathematics [2000], 6.1.1) | |
| A reaction: Real numbers (such as pi and root-2) have infinite decimal expansions, so we can start naming those. We could also start giving names like 'Harry' to other reals, though it might take a while. OK, I give up. |
| 8750 | Game Formalism is just a matter of rules, like chess - but then why is it useful in science? [Shapiro] |
| Full Idea: Game Formalism likens mathematics to chess, where the 'content' of mathematics is exhausted by the rules of operating with its language. ...This, however, leaves the problem of why the mathematical games are so useful to the sciences. | |
| From: Stewart Shapiro (Thinking About Mathematics [2000], 6.1.2) | |
| A reaction: This thought pushes us towards structuralism. It could still be a game, but one we learned from observing nature, which plays its own games. Chess is, after all, modelled on warfare. |
| 8752 | Deductivism says mathematics is logical consequences of uninterpreted axioms [Shapiro] |
| Full Idea: The Deductivist version of formalism (sometimes called 'if-thenism') says that the practice of mathematics consists of determining logical consequences of otherwise uninterpreted axioms. | |
| From: Stewart Shapiro (Thinking About Mathematics [2000], 6.2) | |
| A reaction: [Hilbert is the source] More plausible than Term or Game Formalism (qv). It still leaves the question of why it seems applicable to nature, and why those particular axioms might be chosen. In some sense, though, it is obviously right. |
| 8753 | Critics resent the way intuitionism cripples mathematics, but it allows new important distinctions [Shapiro] |
| Full Idea: Critics commonly complain that the intuitionist restrictions cripple the mathematician. On the other hand, intuitionist mathematics allows for many potentially important distinctions not available in classical mathematics, and is often more subtle. | |
| From: Stewart Shapiro (Thinking About Mathematics [2000], 7.1) | |
| A reaction: The main way in which it cripples is its restriction on talk of infinity ('Cantor's heaven'), which was resented by Hilbert. Since high-level infinities are interesting, it would be odd if we were not allowed to discuss them. |
| 8731 | Conceptualist are just realists or idealist or nominalists, depending on their view of concepts [Shapiro] |
| Full Idea: I classify conceptualists according to what they say about properties or concepts. If someone classified properties as existing independent of language I would classify her as a realist in ontology of mathematics. Or they may be idealists or nominalists. | |
| From: Stewart Shapiro (Thinking About Mathematics [2000], 2.2.1) | |
| A reaction: In other words, Shapiro wants to eliminate 'conceptualist' as a useful label in philosophy of mathematics. He's probably right. All thought involves concepts, but that doesn't produce a conceptualist theory of, say, football. |
| 8730 | 'Impredicative' definitions refer to the thing being described [Shapiro] |
| Full Idea: A definition of a mathematical entity is 'impredicative' if it refers to a collection that contains the defined entity. The definition of 'least upper bound' is impredicative as it refers to upper bounds and characterizes a member of this set. | |
| From: Stewart Shapiro (Thinking About Mathematics [2000], 1.2) | |
| A reaction: The big question is whether mathematics can live with impredicative definitions, or whether they threaten to be viciously circular, and undermine the whole enterprise. |
| 10512 | The abstract/concrete distinction is based on what is perceivable, causal and located [Hale] |
| Full Idea: The 'concrete/abstract' distinction has a strong intuitive feel, and can seem to be drawable by familiar contrasts, between what can/cannot be perceived, what can/cannot be involved in causal interactions, and is/is not located in space and time. | |
| From: Bob Hale (Abstract Objects [1987], Ch.3.I) | |
| A reaction: Problems arise, needless to say. The idea of an abstraction can be causal, and abstractions seem to change. If universals are abstract, we seem to perceive some of them. They can hardly be non-spatial if they have a temporal beginning and end. |
| 10517 | Colours and points seem to be both concrete and abstract [Hale] |
| Full Idea: It might seem that colours would qualify both as concrete and as abstract objects. ...and geometrical points also seem to be borderline. | |
| From: Bob Hale (Abstract Objects [1987], Ch.3.II) | |
| A reaction: The theory of tropes exploits this uncertainty. Dummett (1973:ch.14) notes that we can point to colours, but also slip from an adjectival to a noun usage of colour-terms. He concludes that colours are concrete. I think I agree. |
| 10519 | The abstract/concrete distinction is in the relations in the identity-criteria of object-names [Hale] |
| Full Idea: Noonan suggests that the distinction between abstract and concrete objects should be seen as derivative from a difference between the relations centrally involved in criteria of identity associated with names of objects. | |
| From: Bob Hale (Abstract Objects [1987], Ch.3.III) | |
| A reaction: [He cites Noonan 1976, but I've lost it] I don't understand this, but collect it as a lead to something that might be interesting. A careful reading of Hale might reveal what Noonan meant. |
| 10520 | Token-letters and token-words are concrete objects, type-letters and type-words abstract [Hale] |
| Full Idea: In familiar, though doubtless not wholly problematic jargon, token-letters and token-words are concrete objects, type-letters and type-words abstract. | |
| From: Bob Hale (Abstract Objects [1987], Ch.3.III) | |
| A reaction: This is indeed problematic. The marks may be tokens, but the preliminary to identifying the type is to see that the marks are in fact words. To grasp the concrete, grasp the abstraction. An excellent example of the blurring of the distinction. |
| 10524 | There is a hierarchy of abstraction, based on steps taken by equivalence relations [Hale] |
| Full Idea: The domain of the abstract can be seen as exemplifying a hierarchical structure, with differences of level reflecting the number of steps of abstraction, via appropriate equivalence relations, required for recognition at different levels. | |
| From: Bob Hale (Abstract Objects [1987], Ch.3.III) | |
| A reaction: I think this is right, and so does almost everyone else, since people cheerfully talk of 'somewhat' abstract and 'highly' abstract. Don't dream of a neat picture though. You might reach a level by two steps from one direction, and four from another. |
| 10521 | If F can't have location, there is no problem of things having F in different locations [Hale] |
| Full Idea: If Fs are incapable of spatial location, it is impossible for a and b to be at the same time in different places and yet be the same F. | |
| From: Bob Hale (Abstract Objects [1987], Ch.3.III) | |
| A reaction: A passing remark from Hale which strikes me as incredibly significant. The very idea of a 'one-over-many' is that there are many locations for the thing, so to conclude that the thing is therefore non-located seems to negate the original problem. |
| 10511 | It is doubtful if one entity, a universal, can be picked out by both predicates and abstract nouns [Hale] |
| Full Idea: The traditional conception of universals, resting as it does upon the idea that some single type of entity is picked out by expressions of such radically different logical types as predicates and abstract nouns, is of doubtful coherence. | |
| From: Bob Hale (Abstract Objects [1987], Ch.3 Intro) | |
| A reaction: A striking case of linguistic metaphysics in action. I don't believe in universals, but I don't find this persuasive, as our capacity to express the same proposition by means of extremely varied syntax is obvious. Is 'horse' an abstract noun? |
| 10318 | Realists take universals to be the referrents of both adjectives and of nouns [Hale] |
| Full Idea: On the traditional realist's view abstract qualities (universals) are the common referents of two quite different sorts of expression - of ordinary adjectives (predicates), and of abstract nouns referring to them. | |
| From: Bob Hale (Abstract Objects [1987], Ch.2.II) | |
| A reaction: This fact alone should make us suspicious, especially as there isn't an isomorphism between the nouns and the adjectives, and the match-up will vary between languages. |
| 10310 | Objections to Frege: abstracta are unknowable, non-independent, unstatable, unindividuated [Hale] |
| Full Idea: Objections to Frege's argument for abstract objects: that the objects would not have the right sort of independence; that we could have no knowledge of them; that the singular term statements can't be had; that thoughts of abstracta can't be identified. | |
| From: Bob Hale (Abstract Objects [1987], Ch.1) | |
| A reaction: [compressed] [See Idea 10309 for the original argument] It is helpful to have this list, even if Hale rejects them all. They are also created but then indestructible, and exist in unlimited profusion, and seem relative to a language. Etc! |
| 10782 | The modern concept of an object is rooted in quantificational logic [Linnebo] |
| Full Idea: Our modern general concept of an object is given content only in connection with modern quantificational logic. | |
| From: Øystein Linnebo (Plural Quantification Exposed [2003], §2) | |
| A reaction: [He mentions Frege, Carnap, Quine and Dummett] This is the first thing to tell beginners in modern analytical metaphysics. The word 'object' is very confusing. I think I prefer 'entity'. |
| 10518 | Shapes and directions are of something, but games and musical compositions are not [Hale] |
| Full Idea: While a shape or a direction is necessarily of something, games, musical compositions or dance routines are not of anything at all. | |
| From: Bob Hale (Abstract Objects [1987], Ch.3.II) | |
| A reaction: This seems important, because Frege's abstraction principle works nicely for abstractions 'of' some objects, but is not so clear for abstracta that are sui generis. |
| 10513 | Many abstract objects, such as chess, seem non-spatial, but are not atemporal [Hale] |
| Full Idea: There are many plausible example of abstract objects which, though non-spatial, do not appear to satisfy the suggested requirement of atemporality, such as chess, or the English language. | |
| From: Bob Hale (Abstract Objects [1987], Ch.3.1) | |
| A reaction: Given the point that modern physics is committed to 'space-time', with no conceivable separation of them, this looks dubious. Though I think the physics could be challenged. Try Idea 7621, for example. |
| 10514 | If the mental is non-spatial but temporal, then it must be classified as abstract [Hale] |
| Full Idea: If mental events are genuinely non-spatial, but not atemporal, its effect is to classify them as abstract; the distinction between the abstract and the mental simply collapses. | |
| From: Bob Hale (Abstract Objects [1987], Ch.3.1) | |
| A reaction: This is important. You can't discuss this sort of metaphysics in isolation from debates about the ontology of mind. Functionalists do treat mental events as abstractions. |
| 10523 | Being abstract is based on a relation between things which are spatially separated [Hale] |
| Full Idea: The abstract/concrete distinction is, roughly, between those sortals whose grounding relations can hold between abstract things which are spatially but not temporally separated, those concrete things whose grounding relations cannot so hold. | |
| From: Bob Hale (Abstract Objects [1987], Ch.3.III) | |
| A reaction: Thus being a father is based on 'begat', which does not involve spatial separation, and so is concrete. The relation is one of equivalence. |
| 10307 | The modern Fregean use of the term 'object' is much broader than the ordinary usage [Hale] |
| Full Idea: The notion of an 'object' first introduced by Frege is much broader than that of most comparable ordinary uses of 'object', and is now fairly standard and familiar. | |
| From: Bob Hale (Abstract Objects [1987], Ch.1) | |
| A reaction: This makes it very difficult to get to grips with the metaphysical issues involved, since the ontological claims disappear into a mist of semantic vagueness. |
| 10315 | We can't believe in a 'whereabouts' because we ask 'what kind of object is it?' [Hale] |
| Full Idea: Onotological outrage at such objects as the 'whereabouts of the Prime Minister' derives from the fact that we seem beggared for any convincing answer to the question 'What kind of objects are they?' | |
| From: Bob Hale (Abstract Objects [1987], Ch.2.II) | |
| A reaction: I go further and ask of any object 'what is it made of?' When I receive the answer that I am being silly, and that abstract objects are not 'made' of anything, I am tempted to become sarcastic, and say 'thank you - that makes it much clearer'. |
| 10522 | The relations featured in criteria of identity are always equivalence relations [Hale] |
| Full Idea: The relations which are featured in criteria of identity are always equivalence relations. | |
| From: Bob Hale (Abstract Objects [1987], Ch.3.III) | |
| A reaction: This will only apply to strict identity. If I say 'a is almost identical to b', this will obviously not be endlessly transitive (as when we get to k we may have lost the near-identity to a). Are 'two threes' identical to 'three twos'? |
| 10321 | We sometimes apply identity without having a real criterion [Hale] |
| Full Idea: Not every (apparent) judgement of identity involves application of anything properly describable as a criterion of identity, ...such as being able to pronounce that mercy is the quality of being merciful. | |
| From: Bob Hale (Abstract Objects [1987], Ch.2.II) | |
| A reaction: This suggests some distinction between internal criteria (e.g. grammatical, conceptual) and external criteria (existent, sensed). |
| 8725 | Rationalism tries to apply mathematical methodology to all of knowledge [Shapiro] |
| Full Idea: Rationalism is a long-standing school that can be characterized as an attempt to extend the perceived methodology of mathematics to all of knowledge. | |
| From: Stewart Shapiro (Thinking About Mathematics [2000], 1.1) | |
| A reaction: Sometimes called 'Descartes's Dream', or the 'Enlightenment Project', the dream of proving everything. Within maths, Hilbert's Programme aimed for the same certainty. Idea 22 is the motto for the opposition to this approach. |