91 ideas
| 16325 | Analysis rests on natural language, but its ideal is a framework which revises language [Halbach] |
| Full Idea: For me, although the enterprise of philosophical analysis is driven by natural language, its goal is not a linguistic analysis of English but rather an expressively strong framework that may at best be seen as a revision of English. | |
| From: Volker Halbach (Axiomatic Theories of Truth [2011], 12) | |
| A reaction: I agree, but the problem is that there are different ideals for the revision, which may be in conflict. Logicians, mathematicians, metaphysicians, scientists, moralists and aestheticians are queueing up to improve in their own way. |
| 16292 | An explicit definition enables the elimination of what is defined [Halbach] |
| Full Idea: Explicit definitions allow for a complete elimination of the defined notion (at least in extensional contexts). | |
| From: Volker Halbach (Axiomatic Theories of Truth [2011], 1) | |
| A reaction: If the context isn't extensional (concerning the things themselves) then we could define one description of it, but be unable to eliminate it under another description. Elimination is no the aim of an Aristotelian definition. Halbach refers to truth. |
| 14227 | We could refer to tables as 'xs that are arranged tablewise' [Inwagen] |
| Full Idea: We could paraphrase 'some chairs are heavier than some tables' as 'there are xs that are arranged chairwise and there are ys that are arranged tablewise and the xs are heavier than the ys'. | |
| From: Peter van Inwagen (Material Beings [1990], 11) | |
| A reaction: Liggins notes that this involves plural quantification. Being 'arranged tablewise' has become a rather notorious locution in modern ontology. We still have to retain identity, to pick out the xs. |
| 16307 | Don't trust analogies; they are no more than a guideline [Halbach] |
| Full Idea: Arguments from analogy are to be distrusted: at best they can serve as heuristics. | |
| From: Volker Halbach (Axiomatic Theories of Truth [2011], 4) |
| 16330 | Truth-value 'gluts' allow two truth values together; 'gaps' give a partial conception of truth [Halbach] |
| Full Idea: Truth-value 'gluts' correspond to a so-called dialethic conception of truth; excluding gluts and admitting only 'gaps' leads to a conception of what is usually called 'partial' truth. | |
| From: Volker Halbach (Axiomatic Theories of Truth [2011], 15.2) | |
| A reaction: Talk of 'gaps' and 'gluts' seem to be the neatest way of categorising views of truth. I want a theory with no gaps or gluts. |
| 16339 | Truth axioms prove objects exist, so truth doesn't seem to be a logical notion [Halbach] |
| Full Idea: Two typed disquotation sentences, truth axioms of TB, suffice for proving that there at least two objects. Hence truth is not a logical notion if one expects logical notions to be ontologically neutral. | |
| From: Volker Halbach (Axiomatic Theories of Truth [2011], 21.2) |
| 16324 | Any definition of truth requires a metalanguage [Halbach] |
| Full Idea: It is plain that the distinction between object and metalanguage is required for the definability of truth. | |
| From: Volker Halbach (Axiomatic Theories of Truth [2011], 11) | |
| A reaction: Halbach's axiomatic approach has given up on definability, and therefore it can seek to abandon the metalanguage and examine 'type-free' theories. |
| 16293 | Traditional definitions of truth often make it more obscure, rather than less [Halbach] |
| Full Idea: A common complaint against traditional definitional theories of truth is that it is far from clear that the definiens is not more in need of clarification than the definiendum (that is, the notion of truth). | |
| From: Volker Halbach (Axiomatic Theories of Truth [2011], 1) | |
| A reaction: He refers to concepts like 'correspondence', 'facts', 'coherence' or 'utility', which are said to be trickier to understand than 'true'. I suspect that philosophers like Halbach confuse 'clear' with 'precise'. Coherence is quite clear, but imprecise. |
| 16301 | If people have big doubts about truth, a definition might give it more credibility [Halbach] |
| Full Idea: If one were wondering whether truth should be considered a legitimate notion at all, a definition might be useful in dispersing doubts about its legitimacy. | |
| From: Volker Halbach (Axiomatic Theories of Truth [2011], 3) | |
| A reaction: Halbach is proposing to skip definitions, and try to give rules for using 'true' instead, but he doesn't rule out definitions. A definition of 'knowledge' or 'virtue' or 'democracy' might equally give those credibility. |
| 16297 | Semantic theories avoid Tarski's Theorem by sticking to a sublanguage [Halbach] |
| Full Idea: In semantic theories (e.g.Tarski's or Kripke's), a definition evades Tarski's Theorem by restricting the possible instances in the schema T[φ]↔φ to sentences of a proper sublanguage of the language formulating the equivalences. | |
| From: Volker Halbach (Axiomatic Theories of Truth [2011], 1) | |
| A reaction: The schema says if it's true it's affirmable, and if it's affirmable it's true. The Liar Paradox is a key reason for imposing this restriction. |
| 16337 | Disquotational truth theories are short of deductive power [Halbach] |
| Full Idea: The problem of restricted deductive power has haunted disquotational theories of truth (…because they can't prove generalisations). | |
| From: Volker Halbach (Axiomatic Theories of Truth [2011], 19.5) |
| 16322 | CT proves PA consistent, which PA can't do on its own, so CT is not conservative over PA [Halbach] |
| Full Idea: Compositional Truth CT proves the consistency of Peano arithmetic, which is not provable in Peano arithmetic by Gödel's second incompleteness theorem. Hence the theory CT is not conservative over Peano arithmetic. | |
| From: Volker Halbach (Axiomatic Theories of Truth [2011], 8.6) |
| 16294 | Axiomatic truth doesn't presuppose a truth-definition, though it could admit it at a later stage [Halbach] |
| Full Idea: Choosing an axiomatic approach to truth might well be compatible with the view that truth is definable; the definability of truth is just not presupposed at the outset. | |
| From: Volker Halbach (Axiomatic Theories of Truth [2011], 1) | |
| A reaction: Is it possible that a successful axiomatisation is a successful definition? |
| 16326 | The main semantic theories of truth are Kripke's theory, and revisions semantics [Halbach] |
| Full Idea: Revision semantics is arguably the main competitor of Kripke's theory of truth among semantic truth theories. …In the former one may hope through revision to arrive at better and better models, ..sorting out unsuitable extensions of the truth predicate. | |
| From: Volker Halbach (Axiomatic Theories of Truth [2011], 14) | |
| A reaction: Halbach notes later that Kripke's theory (believe it or not) is considerably simpler than revision semantics. |
| 16311 | To axiomatise Tarski's truth definition, we need a binary predicate for his 'satisfaction' [Halbach] |
| Full Idea: If the clauses of Tarski's definition of truth are turned into axioms (as Davidson proposed) then a primitive binary predicate symbol for satisfaction is needed, as Tarski defined truth in terms of satisfaction. Standard language has a unary predicate. | |
| From: Volker Halbach (Axiomatic Theories of Truth [2011], 5.2) |
| 16318 | Compositional Truth CT has the truth of a sentence depending of the semantic values of its constituents [Halbach] |
| Full Idea: In the typed Compositional Truth theory CT, it is compositional because the truth of a sentence depends on the semantic values of the constituents of that sentence. | |
| From: Volker Halbach (Axiomatic Theories of Truth [2011], 8) | |
| A reaction: [axioms on p. 65 of Halbach] |
| 16299 | Gödel numbering means a theory of truth can use Peano Arithmetic as its base theory [Halbach] |
| Full Idea: Often syntactic objects are identified with their numerical codes. …Expressions of a countable formal language can be coded in the natural numbers. This allows a theory of truth to use Peano Arithmetic (with its results) as a base theory. | |
| From: Volker Halbach (Axiomatic Theories of Truth [2011], 2) | |
| A reaction: The numbering system is the famous device invented by Gödel for his great proof of incompleteness. This idea is a key to understanding modern analytic philosophy. It is the bridge which means philosophical theories can be treated mathematically. |
| 16340 | Truth axioms need a base theory, because that is where truth issues arise [Halbach] |
| Full Idea: Considering the truth axioms in the absence of a base theory is not very sensible because characteristically truth theoretic reasoning arises from the interplay of the truth axioms with the base theory. | |
| From: Volker Halbach (Axiomatic Theories of Truth [2011], 21.2) | |
| A reaction: The base theory usually seems to be either Peano arithmetic or set theory. We might say that introverted thought (e.g. in infants) has little use for truth; it is when you think about the world that truth becomes a worry. |
| 16305 | We know a complete axiomatisation of truth is not feasible [Halbach] |
| Full Idea: In the light of incompleteness phenomena, one should not expect a categorical axiomatisation of truth to be feasible, but this should not keep one from studying axiomatic theories of truth (or of arithmetic). | |
| From: Volker Halbach (Axiomatic Theories of Truth [2011], 3) | |
| A reaction: This, of course, is because of Gödel's famous results. It is important to be aware in this field that there cannot be a dream of a final theory, so we are just seeing what can be learned about truth. |
| 16313 | A theory is 'conservative' if it adds no new theorems to its base theory [Halbach, by PG] |
| Full Idea: A truth theory is 'conservative' if the addition of the truth predicate does not add any new theorems to the base theory. | |
| From: report of Volker Halbach (Axiomatic Theories of Truth [2011], 6 Df 6.6) by PG - Db (ideas) | |
| A reaction: Halbach presents the definition more formally, and this is my attempt at getting it into plain English. Halbach uses Peano Arithmetic as his base theory, but set theory is also sometimes used. |
| 16315 | The Tarski Biconditional theory TB is Peano Arithmetic, plus truth, plus all Tarski bi-conditionals [Halbach] |
| Full Idea: The truth theory TB (Tarski Biconditional) is all the axioms of Peano Arithmetic, including all instances of the induction schema with the truth predicate, plus all the sentences of the form T[φ] ↔ φ. | |
| From: Volker Halbach (Axiomatic Theories of Truth [2011], 7) | |
| A reaction: The biconditional formula is the famous 'snow is white' iff snow is white. The truth of the named sentence is equivalent to asserting the sentence. This is a typed theory of truth, and it is conservative over PA. |
| 16314 | Theories of truth are 'typed' (truth can't apply to sentences containing 'true'), or 'type-free' [Halbach] |
| Full Idea: I sort theories of truth into the large families of 'typed' and 'type-free'. Roughly, typed theories prohibit a truth predicate's application to sentences with occurrences of that predicate, and one cannot prove the truth of sentences containing 'true'. | |
| From: Volker Halbach (Axiomatic Theories of Truth [2011], II Intro) | |
| A reaction: The problem sentence the typed theories are terrified of is the Liar Sentence. Typing produces a hierarchy of languages, referring down to the languages below them. |
| 16327 | Friedman-Sheard is type-free Compositional Truth, with two inference rules for truth [Halbach] |
| Full Idea: The Friedman-Sheard truth system FS is based on compositional theory CT. The axioms of FS are obtained by relaxing the type restriction on the CT-axioms, and adding rules inferring sentences from their truth, and vice versa. | |
| From: Volker Halbach (Axiomatic Theories of Truth [2011], 15) | |
| A reaction: The rules are called NEC and CONEC by Halbach. The system FSN is FS without the two rules. |
| 16332 | The KF theory is useful, but it is not a theory containing its own truth predicate [Halbach] |
| Full Idea: KF is useful for explicating Peano arithmetic, but it certainly does not come to close to being a theory that contains its own truth predicate. | |
| From: Volker Halbach (Axiomatic Theories of Truth [2011], 16) | |
| A reaction: Since it is a type-free theory, its main philosophical aspiration was to contain its own truth predicate, so that is bad news (for philosophers). |
| 16331 | The KF is much stronger deductively than FS, which relies on classical truth [Halbach] |
| Full Idea: The Kripke-Feferman theory is relatively deductively very strong. In particular, it is much stronger than its competitor FS, which is based on a completely classical notion of truth. | |
| From: Volker Halbach (Axiomatic Theories of Truth [2011], 15.3) |
| 16329 | Kripke-Feferman theory KF axiomatises Kripke fixed-points, with Strong Kleene logic with gluts [Halbach] |
| Full Idea: The Kripke-Feferman theory KF is an axiomatisation of the fixed points of an operator, that is, of a Kripkean fixed-point semantics with the Strong Kleene evaluation schema with truth-value gluts. | |
| From: Volker Halbach (Axiomatic Theories of Truth [2011], 15.1) |
| 16319 | Compositional Truth CT proves generalisations, so is preferred in discussions of deflationism [Halbach] |
| Full Idea: Compositional Truth CT and its variants has desirable generalisations among its logical consequences, so they seem to have ousted purely disquotational theories such as TB in the discussion on deflationism. | |
| From: Volker Halbach (Axiomatic Theories of Truth [2011], 8) |
| 16320 | Some say deflationism is axioms which are conservative over the base theory [Halbach] |
| Full Idea: Some authors have tried to understand the deflationist claim that truth is not a substantial notion as the claim that a satisfactory axiomatisation of truth should be conservative over the base theory. | |
| From: Volker Halbach (Axiomatic Theories of Truth [2011], 8) |
| 16338 | Deflationism says truth is a disquotation device to express generalisations, adding no new knowledge [Halbach] |
| Full Idea: There are two doctrines at the core of deflationism. The first says truth is a device of disquotation used to express generalisations, and the second says truth is a thin notion that contributes nothing to our knowledge of the world | |
| From: Volker Halbach (Axiomatic Theories of Truth [2011], 21) |
| 16317 | The main problem for deflationists is they can express generalisations, but not prove them [Halbach] |
| Full Idea: The main criticism that deflationist theories based on the disquotation sentences or similar axioms have to meet was raised by Tarski: the disquotation sentences do not allow one to prove generalisations. | |
| From: Volker Halbach (Axiomatic Theories of Truth [2011], 7) |
| 16316 | Deflationists say truth is just for expressing infinite conjunctions or generalisations [Halbach] |
| Full Idea: Deflationists do not hold that truth is completely dispensable. They claim that truth serves the purpose of expressing infinite conjunctions or generalisations. | |
| From: Volker Halbach (Axiomatic Theories of Truth [2011], 7) | |
| A reaction: It is also of obvious value as a shorthand in ordinary conversation, but rigorous accounts can paraphrase that out. 'What he said is true'. 'Pick out the true sentences from p,q,r and s' seems to mean 'affirm some of them'. What does 'affirm' mean? |
| 16335 | In Strong Kleene logic a disjunction just needs one disjunct to be true [Halbach] |
| Full Idea: In Strong Kleene logic a disjunction of two sentences is true if at least one disjunct is true, even when the other disjunct lacks a truth value. | |
| From: Volker Halbach (Axiomatic Theories of Truth [2011], 18) | |
| A reaction: This sounds fine to me. 'Either I'm typing this or Homer had blue eyes' comes out true in any sensible system. |
| 16334 | In Weak Kleene logic there are 'gaps', neither true nor false if one component lacks a truth value [Halbach] |
| Full Idea: In Weak Kleene Logic, with truth-value gaps, a sentence is neither true nor false if one of its components lacks a truth value. A line of the truth table shows a gap if there is a gap anywhere in the line, and the other lines are classical. | |
| From: Volker Halbach (Axiomatic Theories of Truth [2011], 18) | |
| A reaction: This will presumably apply even if the connective is 'or', so a disjunction won't be true, even if one disjunct is true, when the other disjunct is unknown. 'Either 2+2=4 or Lot's wife was left-handed' sounds true to me. Odd. |
| 16309 | Every attempt at formal rigour uses some set theory [Halbach] |
| Full Idea: Almost any subject with any formal rigour employs some set theory. | |
| From: Volker Halbach (Axiomatic Theories of Truth [2011], 4.1) | |
| A reaction: This is partly because mathematics is often seen as founded in set theory, and formal rigour tends to be mathematical in character. |
| 10662 | Mereology is 'nihilistic' (just atoms) or 'universal' (no restrictions on what is 'whole') [Inwagen, by Varzi] |
| Full Idea: Van Ingwagen writes of 'mereological nihilism' (that only mereological atoms exist) and of 'mereological universalism' (adhering to the principle of Unrestricted Composition). | |
| From: report of Peter van Inwagen (Material Beings [1990], p.72-) by Achille Varzi - Mereology 4.3 | |
| A reaction: They both look mereologically nihilistic to me, in comparison with an account that builds on 'natural' wholes and their parts. You can only be 'unrestricted' if you view the 'wholes' in your vast ontology as pretty meaningless (as Lewis does, Idea 10660). |
| 16333 | The underestimated costs of giving up classical logic are found in mathematical reasoning [Halbach] |
| Full Idea: The costs of giving up classical logic are easily underestimated, …the price being paid in terms of mathematical reasoning. | |
| From: Volker Halbach (Axiomatic Theories of Truth [2011], 16.2) | |
| A reaction: No one cares much about such costs, until you say they are 'mathematical'. Presumably this is a message to Graham Priest and his pals. |
| 17587 | The 'Law' of Excluded Middle needs all propositions to be definitely true or definitely false [Inwagen] |
| Full Idea: I think the validity of the 'Law' of Excluded Middle depends on the assumption that every proposition is definitely true or definitely false. | |
| From: Peter van Inwagen (Material Beings [1990], 18) | |
| A reaction: I think this is confused. He cites vagueness as the problem, but that is a problem for Bivalence. If excluded middle is read as 'true or not-true', that leaves the meaning of 'not-true' open, and never mentions the bivalent 'false'. |
| 17558 | Variables are just like pronouns; syntactic explanations get muddled over dummy letters [Inwagen] |
| Full Idea: Explanations in terms of syntax do not satisfactorily distinguish true variables from dummy or schematic letters. Identifying variables with pronouns, however, provides a genuine explanation of what variables are. | |
| From: Peter van Inwagen (Material Beings [1990], 02) | |
| A reaction: I like this because it shows that our ordinary thought and speech use variables all the time ('I've forgotten something - what was it?'). He says syntax is fine for maths, but not for ordinary understanding. |
| 16310 | A theory is some formulae and all of their consequences [Halbach] |
| Full Idea: A theory is a set of formulae closed under first-order logical consequence. | |
| From: Volker Halbach (Axiomatic Theories of Truth [2011], 5.1) |
| 16342 | You cannot just say all of Peano arithmetic is true, as 'true' isn't part of the system [Halbach] |
| Full Idea: One cannot just accept that all the theorems of Peano arithmetic are true when one accepts Peano arithmetic as the notion of truth is not available in the language of arithmetic. | |
| From: Volker Halbach (Axiomatic Theories of Truth [2011], 22.1) | |
| A reaction: This is given as the reason why Kreisel and Levy (1968) introduced 'reflection principles', which allow you to assert whatever has been proved (with no mention of truth). (I think. The waters are closing over my head). |
| 16341 | Normally we only endorse a theory if we believe it to be sound [Halbach] |
| Full Idea: If one endorses a theory, so one might argue, one should also take it to be sound. | |
| From: Volker Halbach (Axiomatic Theories of Truth [2011], 22.1) |
| 16344 | Soundness must involve truth; the soundness of PA certainly needs it [Halbach] |
| Full Idea: Soundness seems to be a notion essentially involving truth. At least I do not know how to fully express the soundness of Peano arithmetic without invoking a truth predicate. | |
| From: Volker Halbach (Axiomatic Theories of Truth [2011], 22.1) | |
| A reaction: I suppose you could use some alternative locution such as 'assertible' or 'cuddly'. Intuitionists seem a bit vague about the truth end of things. |
| 16347 | Many new paradoxes may await us when we study interactions between frameworks [Halbach] |
| Full Idea: Paradoxes that arise from interaction of predicates such as truth, necessity, knowledge, future and past truths have receive little attention. There may be many unknown paradoxes lurking when we develop frameworks with these intensional notions. | |
| From: Volker Halbach (Axiomatic Theories of Truth [2011], 24.2) | |
| A reaction: Nice. This is a wonderful pointer to new research in the analytic tradition, in which formal problems will gradually iron out our metaphysical framework. |
| 16336 | The liar paradox applies truth to a negated truth (but the conditional will serve equally) [Halbach] |
| Full Idea: An essential feature of the liar paradox is the application of the truth predicate to a sentence with a negated occurrence of the truth predicate, though the negation can be avoided by using the conditional. | |
| From: Volker Halbach (Axiomatic Theories of Truth [2011], 19.3) |
| 17583 | There are no heaps [Inwagen] |
| Full Idea: Fortunately ....there are no heaps. | |
| From: Peter van Inwagen (Material Beings [1990], 18) | |
| A reaction: This is the nihilist view of (inorganic) physical objects. If a wild view solves all sorts of problems, one should take it serious. It is why I take reductive physicalism about the mind seriously. (Well, it's true, actually) |
| 16321 | The compactness theorem can prove nonstandard models of PA [Halbach] |
| Full Idea: Nonstandard models of Peano arithmetic are models of PA that are not isomorphic to the standard model. Their existence can be established with the compactness theorem or the adequacy theorem of first-order logic. | |
| From: Volker Halbach (Axiomatic Theories of Truth [2011], 8.3) |
| 16343 | The global reflection principle seems to express the soundness of Peano Arithmetic [Halbach] |
| Full Idea: The global reflection principle ∀x(Sent(x) ∧ Bew[PA](x) → Tx) …seems to be the full statement of the soundness claim for Peano arithmetic, as it expresses that all theorems of Peano arithmetic are true. | |
| From: Volker Halbach (Axiomatic Theories of Truth [2011], 22.1) | |
| A reaction: That is, an extra principle must be introduced to express the soundness. PA is, of course, not complete. |
| 16312 | To reduce PA to ZF, we represent the non-negative integers with von Neumann ordinals [Halbach] |
| Full Idea: For the reduction of Peano Arithmetic to ZF set theory, usually the set of finite von Neumann ordinals is used to represent the non-negative integers. | |
| From: Volker Halbach (Axiomatic Theories of Truth [2011], 6) | |
| A reaction: Halbach makes it clear that this is just one mode of reduction, relative interpretability. |
| 16308 | Set theory was liberated early from types, and recent truth-theories are exploring type-free [Halbach] |
| Full Idea: While set theory was liberated much earlier from type restrictions, interest in type-free theories of truth only developed more recently. | |
| From: Volker Halbach (Axiomatic Theories of Truth [2011], 4) | |
| A reaction: Tarski's theory of truth involves types (or hierarchies). |
| 16345 | That Peano arithmetic is interpretable in ZF set theory is taken by philosophers as a reduction [Halbach] |
| Full Idea: The observation that Peano arithmetic is relatively interpretable in ZF set theory is taken by many philosophers to be a reduction of numbers to sets. | |
| From: Volker Halbach (Axiomatic Theories of Truth [2011], 23) | |
| A reaction: Nice! Being able to express something in a different language is not the same as a reduction. Back to the drawing board. What do you really mean by a reduction? If we model something, we don't 'reduce' it to the model. |
| 17578 | I reject talk of 'stuff', and treat it in terms of particles [Inwagen] |
| Full Idea: I have a great deal of difficulty with an ontology that includes 'stuffs' in addition to things. ...I prefer to replace talk of sameness of matter with talk of sameness of particles. | |
| From: Peter van Inwagen (Material Beings [1990], 14) | |
| A reaction: Van Inwagen is wedded to the idea that reality is composed of 'simples' - even if physicists seem now to talk of 'fields' as much as they do about objects in the fields. Has philosophy yet caught up with Maxwell? |
| 17582 | Singular terms can be vague, because they can contain predicates, which can be vague [Inwagen] |
| Full Idea: Since singular terms can contain predicates, and since vague predicates are common, vague singular terms are common. For 'the tallest man that Sally knows' there are lots of men for whom it is unclear whether Sally knows them. | |
| From: Peter van Inwagen (Material Beings [1990], 17) |
| 17556 | Material objects are in space and time, move, have a surface and mass, and are made of some stuff [Inwagen] |
| Full Idea: A thing is a material object if it occupies space and endures through time and can move about in space (literally move, unlike a shadow or wave or reflection) and has a surface and has a mass and is made of a certain stuff or stuffs. | |
| From: Peter van Inwagen (Material Beings [1990], 01) | |
| A reaction: It is not at all clear what electrons (which must count for him as 'simples') are made of. |
| 8264 | Maybe table-shaped particles exist, but not tables [Inwagen, by Lowe] |
| Full Idea: Van Ingwagen holds that although table-shaped collections of particles exist, tables do not. | |
| From: report of Peter van Inwagen (Material Beings [1990], Ch.13) by E.J. Lowe - The Possibility of Metaphysics 2.3 | |
| A reaction: I find this idea appealing. See the ideas of Trenton Merricks. When you get down to micro-level, it is hard to individuate a table among the force fields, and hard to distinguish a table from a smashed or burnt table. An ontology without objects? |
| 17565 | Nihilism says composition between single things is impossible [Inwagen] |
| Full Idea: Nihilism about objects says there is a Y such that the Xs compose it if and only if there is only one of the Xs. | |
| From: Peter van Inwagen (Material Beings [1990], 08) | |
| A reaction: He says that Unger, the best known 'nihilist' about objects, believes a different version - claiming there are composites, but they never make up the ordinary objects we talk about. |
| 14228 | If there are no tables, but tables are things arranged tablewise, the denial of tables is a contradiction [Liggins on Inwagen] |
| Full Idea: Van Inwagen says 'there are no tables', and 'there are tables' means 'there are some things arranged tablewise'. Presumably 'there are no tables' negates the latter claim, saying no things are arranged tablewise. But he should think that is false. | |
| From: comment on Peter van Inwagen (Material Beings [1990], 10) by David Liggins - Nihilism without Self-Contradiction 3 | |
| A reaction: Liggins's nice paper shows that Van Inwagen is in a potential state of contradiction when he starts saying that there are no tables, but that there are things arranged tablewise, and that they amount to tables. Liggins offers him an escape. |
| 14468 | Actions by artefacts and natural bodies are disguised cooperations, so we don't need them [Inwagen] |
| Full Idea: All the activities apparently carried out by shelves and stars and other artefacts and natural bodies can be understood as disguised cooperative activities. And, therefore, we are not forced to grant existence to any artefacts or natural bodies. | |
| From: Peter van Inwagen (Material Beings [1990], 12) | |
| A reaction: In 'the crowd tore her to pieces' are we forced to accept the existence of a crowd? We can't say 'Jack tore her to pieces' and 'Jill tore her to pieces'. If a plural quantification is unavoidable, we have to accept the plurality. Perhaps. |
| 17571 | Every physical thing is either a living organism or a simple [Inwagen] |
| Full Idea: The thesis about composition and parthood that I am advocating has far-reaching ontological consequences: that every physical thing is either a living organism or a simple. | |
| From: Peter van Inwagen (Material Beings [1990], 10) | |
| A reaction: A 'simple' is a placeholder for anything considered to be a fundamental unit of existence (such as an electron or a quark). This amazingly sharp distinction strikes me as utterly implausible. There is too much in the middle ground. |
| 17562 | The statue and lump seem to share parts, but the statue is not part of the lump [Inwagen] |
| Full Idea: Those who believe that the statue is distinct from the lump should concede that whatever shares a part with the statue shares a part with the lump but deny that the statue is a part of the lump. | |
| From: Peter van Inwagen (Material Beings [1990], 05) | |
| A reaction: Standard mereology says if they share all their parts then they are the same thing, so it is hard to explain how they are 'distinct'. The distinction is only modal - that they could be separated (by squashing, or by part substitution). |
| 17574 | If you knead clay you make an infinite series of objects, but they are rearrangements, not creations [Inwagen] |
| Full Idea: If you can make a (random) gollyswoggle by accident by kneading clay, then you must be causing the generation and corruption of a series of objects of infinitesimal duration. ...We have not augmented the furniture of the world but only rearranged it. | |
| From: Peter van Inwagen (Material Beings [1990], 13) | |
| A reaction: Van Inwagen's final conclusion is a bit crazy, but I am in sympathy with his general scepticism about what sorts of things definitively constitute 'objects'. He overrates simples, and he overrates lives. |
| 17531 | I assume matter is particulate, made up of 'simples' [Inwagen] |
| Full Idea: I assume in this book that matter is ultimately particulate. Every material being is composed of things that have no proper parts: 'elementary particles' or 'mereological atoms' or 'metaphysical simples'. | |
| From: Peter van Inwagen (Material Beings [1990], Pref) | |
| A reaction: It may be that modern physics doesn't support this, if 'fields' is the best term for what is fundamental. Best to treat his book as hypothetical - IF there are just simples, proceed as follows. |
| 17560 | If contact causes composition, do two colliding balls briefly make one object? [Inwagen] |
| Full Idea: If composition just requires contact, if I cause the cue ball to rebound from the eight ball, do I thereby create a short-lived object shaped like two slightly flattened spheres in contact? | |
| From: Peter van Inwagen (Material Beings [1990], 03) | |
| A reaction: [compressed] |
| 17561 | If bricks compose a house, that is at least one thing, but it might be many things [Inwagen] |
| Full Idea: If composition just requires contact, that tells us that the bricks of a house compose at least one thing; it does not tell us that they also compose at most one thing. | |
| From: Peter van Inwagen (Material Beings [1990], 04) |
| 17566 | I think parthood involves causation, and not just a reasonably stable spatial relationship [Inwagen] |
| Full Idea: I propose that parthood essentially involves causation. Too many philosophers have supposed that objects compose something when and only when they stand in some (more or less stable) spatial relationship to one another. | |
| From: Peter van Inwagen (Material Beings [1990], 09) | |
| A reaction: I have to say that I like this, even though it comes from a thinker who is close to nihilism about ordinary non-living objects. He goes on to say that only a 'life' provides the right sort of causal relationship. |
| 14230 | We can deny whole objects but accept parts, by referring to them as plurals within things [Inwagen, by Liggins] |
| Full Idea: Van Inwagen's claim that nothing has parts causes incredulity. ..But the problem is not with endorsing the sentence 'Some things have parts'; it is with interpreting this sentence by means of singular resources rather than plural ones. | |
| From: report of Peter van Inwagen (Material Beings [1990], 7) by David Liggins - Nihilism without Self-Contradiction | |
| A reaction: Van Inwagen notoriously denies the existence of normal physical objects. Liggins shows that modern formal plural quantification gives a better way of presenting his theory, by accepting tables and parts of tables as plurals of basic entities. |
| 17557 | Special Composition Question: when is a thing part of something? [Inwagen] |
| Full Idea: The Special Composition Question asks, In what circumstances is a thing a (proper) part of something? | |
| From: Peter van Inwagen (Material Beings [1990], 02) | |
| A reaction: [He qualifies this formulation as 'misleading'] It's a really nice basic question for the metaphysics of objects. |
| 17564 | The essence of a star includes the released binding energy which keeps it from collapse [Inwagen] |
| Full Idea: I think it is part of the essence of a star that the radiation pressures that oppose the star's tendency to gravitational collapse has its source in the release of no-longer-needed nuclear binding energy when colliding nuclei fuse in the star's hot core. | |
| From: Peter van Inwagen (Material Beings [1990], 07) | |
| A reaction: A perfect example of giving the essence of something as the bottom level of its explanation. This even comes from someone who doesn't really believe in stars! |
| 17575 | The persistence of artifacts always covertly involves intelligent beings [Inwagen] |
| Full Idea: Statements that are apparently about the persistence of artifacts make covert reference to the dispositions of intelligent beings to maintain certain arrangements of matter. | |
| From: Peter van Inwagen (Material Beings [1990], 13) | |
| A reaction: If you build a self-sustaining windmill that pumps water, that seems to have an identity of its own, apart from the intentions of whoever makes it and repairs it. The function of an artefact is not just the function we want it to have. |
| 17577 | When an electron 'leaps' to another orbit, is the new one the same electron? [Inwagen] |
| Full Idea: Is the 'new' electron in the lower orbit the one that was in the higher orbit? Physics, as far as I can tell, has nothing to say about this. | |
| From: Peter van Inwagen (Material Beings [1990], 14) | |
| A reaction: I suspect that physicists would say that philosophers are worrying about such questions because they haven't grasped the new conceptual scheme that emerged in 1926. The poor mutts insist on hanging on to 'objects'. |
| 17589 | If you reject transitivity of vague identity, there is no Ship of Theseus problem [Inwagen] |
| Full Idea: If you have rejected the Principle of the Transitivity of (vague) Identity, it is hard to see how the problem of the Ship of Theseus could arise. | |
| From: Peter van Inwagen (Material Beings [1990], 18) | |
| A reaction: I think this may well be the best solution to the whole problem |
| 17588 | We should talk of the transitivity of 'identity', and of 'definite identity' [Inwagen] |
| Full Idea: In some contexts, the principle of 'the transitivity of identity' should be called 'the transitivity of definite identity'. | |
| From: Peter van Inwagen (Material Beings [1990], 18) | |
| A reaction: He is making room for a person to retain identity despite having changed. Applause from me. |
| 16346 | Maybe necessity is a predicate, not the usual operator, to make it more like truth [Halbach] |
| Full Idea: Should necessity be treated as a predicate rather than (as in modal logic) as a sentential operator? It is odd to assign different status to necessity and truth, hampering their interaction. That all necessities are true can't be expressed by an operator. | |
| From: Volker Halbach (Axiomatic Theories of Truth [2011], 24.2) | |
| A reaction: [compressed] Halbach and Horsten consistently treat truth as a predicate, but maybe truth is an operator. Making necessity a predicate and not an operator would be a huge upheaval in the world of modal logic. Nice move! |
| 17572 | Actuality proves possibility, but that doesn't explain how it is possible [Inwagen] |
| Full Idea: A proof of actuality is a proof of possibility, but that does not invariably explain the possibility whose existence it demonstrates, for we may know that a certain thing is actual (and hence possible) but have no explanation of how it could be possible. | |
| From: Peter van Inwagen (Material Beings [1990], 12) | |
| A reaction: I like this, because my project is to see all of philosophy in terms of explanation rather than of description. |
| 17579 | Counterparts reduce counterfactual identity to problems about similarity relations [Inwagen] |
| Full Idea: Counterpart Theory essentially reduces all problems about counterfactual identity to problems about choosing appropriate similarity relations. That is, Counterpart Theory essentially eliminates problems of counterfactual identity as such. | |
| From: Peter van Inwagen (Material Beings [1990], 14) |
| 17590 | A merely possible object clearly isn't there, so that is a defective notion [Inwagen] |
| Full Idea: The notion of a merely possible object is an even more defective notion than the notion of a borderline object; after all, a merely possible object is an object that definitely isn't there. | |
| From: Peter van Inwagen (Material Beings [1990], 19) |
| 17591 | Merely possible objects must be consistent properties, or haecceities [Inwagen] |
| Full Idea: Talk of merely possible objects may be redeemed in either maximally consistent sets of properties or in haecceities. | |
| From: Peter van Inwagen (Material Beings [1990], 19) |
| 23224 | That all matter thinks is absurd, and would make each part of our bodies a distinct self-consciousness [Bentley] |
| Full Idea: [Belief in thinking matter] leads to monstrous absurdities. …Every stock and stone would be a percipient and rational creature. …every single Atom of our bodies would be a distinct Animal, endued with self-consciousness and personal sensation of its own. | |
| From: Richard Bentley (Matter and Motion Cannot Think [1692], p.14-15), quoted by Matthew Cobb - The Idea of the Brain 2 | |
| A reaction: Sounds correct, though presumably panpsychists don't think the flickers of consciousness in my toenails and hair constitute full-blown persons. I can't imagine what awareness is being claimed for my toenails. |
| 16298 | We need propositions to ascribe the same beliefs to people with different languages [Halbach] |
| Full Idea: Being able to ascribe the same proposition as a belief to persons who do not have a common language seems to be one of the main reasons to employ propositions. | |
| From: Volker Halbach (Axiomatic Theories of Truth [2011], 2) | |
| A reaction: Propositions concern beliefs, as well as sentence meanings. I would want to say that a dog and I could believe the same thing, and that is a non-linguistic reason to believe in propositions. Maybe 'translation' cuts out the proposition middleman? |
| 17563 | The strong force pulls, but also pushes apart if nucleons get too close together [Inwagen] |
| Full Idea: The strong force doesn't always pull nucleons together, but pushes them apart if they get too close. | |
| From: Peter van Inwagen (Material Beings [1990], 07) | |
| A reaction: Philosophers tend to learn their physics from other philosophers. But that's because philosophers are brilliant at picking out the interesting parts of physics, and skipping the boring stuff. |
| 17559 | Is one atom a piece of gold, or is a sizable group of atoms required? [Inwagen] |
| Full Idea: A physicist once told me that of course a gold atom was a piece of gold, and a physical chemist has assured me that the smallest possible piece of gold would have to be composed of sixteen or seventeen atoms. | |
| From: Peter van Inwagen (Material Beings [1990], 01) | |
| A reaction: The issue is at what point all the properties that we normally begin to associate with gold begin to appear. One water molecule can hardly have a degree of viscosity or liquidity. |
| 17586 | At the lower level, life trails off into mere molecular interaction [Inwagen] |
| Full Idea: The lives of the lower links of the Great Chain of Being trail off into vague, temporary episodes of molecular interaction. | |
| From: Peter van Inwagen (Material Beings [1990], 18) | |
| A reaction: His case involves conceding all sorts of vagueness to life, but asserting the utter distinctness of the full blown cases of more elaborate life. I don't really concede the distinction. |
| 17568 | A tumour may spread a sort of life, but it is not a life, or an organism [Inwagen] |
| Full Idea: A tumour is not an organism (or a parasite) and there is no self-regulating event that is its life. It does not fill one space, but is a locus within which a certain sort of thing is happening: the spreading of a certain sort of (mass-term) life. | |
| From: Peter van Inwagen (Material Beings [1990], 09) |
| 17581 | Being part of an organism's life is a matter of degree, and vague [Inwagen] |
| Full Idea: Being caught up in the life of an organism is, like being rich or being tall, a matter of degree, and is in that sense a vague condition. | |
| From: Peter van Inwagen (Material Beings [1990], 17) | |
| A reaction: Van Inwagen is trying to cover himself, given that he makes a sharp distinction between living organisms, which are unified objects, and everything else, which isn't. There may be a vague centre to a 'life', as well as vague boundaries. |
| 17567 | A flame is like a life, but not nearly so well individuated [Inwagen] |
| Full Idea: A flame, though it is a self-maintaining event, does not seem to be nearly so well individuated as a life. | |
| From: Peter van Inwagen (Material Beings [1990], 09) | |
| A reaction: This is to counter the standard problem that if you attempt to define 'life', fire turns out to tick nearly all the same boxes. The concept of 'individuated' often strikes me as unsatisfactory. How does a bonfire fail to be individuated? |
| 17576 | If God were to 'reassemble' my atoms of ten years ago, the result would certainly not be me [Inwagen] |
| Full Idea: If God were to 'reassemble' the atoms that composed me ten years ago, the resulting organism would certainly not be me. | |
| From: Peter van Inwagen (Material Beings [1990], 13) | |
| A reaction: What is obvious to Van Inwagen is not obvious to me. He thinks lives are special. Such examples just leave us bewildered about what counts as 'the same', because our concept of sameness wasn't designed to deal with such cases. |
| 17570 | The chemical reactions in a human life involve about sixteen elements [Inwagen] |
| Full Idea: There are sixteen or so chemical elements involved in those chemical reactions that collectively constitute the life of a human being. | |
| From: Peter van Inwagen (Material Beings [1990], 09) |
| 17585 | Life is vague at both ends, but could it be totally vague? [Inwagen] |
| Full Idea: Individual human lives are infected with vagueness at both ends. ...But could there be a 'borderline life'? | |
| From: Peter van Inwagen (Material Beings [1990], 18) | |
| A reaction: Van Inwagen says (p.239) that there may be wholly vague lives, though it would suit his case better if there were not. |
| 17584 | Some events are only borderline cases of lives [Inwagen] |
| Full Idea: There are events of which it is neither definitely true nor definitely false that those events are lives. I do not see how we can deny this. | |
| From: Peter van Inwagen (Material Beings [1990], 18) | |
| A reaction: Very frustrating, since this is my main objection to Van Inwagen's distinction between unified lives and mere collections of simples. Some boundaries are real enough, despite their vagueness, and others indicate that there is no real distinction. |
| 17569 | Unlike waves, lives are 'jealous'; it is almost impossible for them to overlap [Inwagen] |
| Full Idea: A wave is not a 'jealous' event. Lives, however, are jealous. It cannot be that the activities of the Xs constitute at one and the same time two lives. Only in certain special cases can two lives overlap. | |
| From: Peter van Inwagen (Material Beings [1990], 09) |
| 17580 | One's mental and other life is centred on the brain, unlike any other part of the body [Inwagen] |
| Full Idea: One's life - not simply one's mental life - is centered in the activity of the simples that virtually compose one's brain in a way in which it is not centered in the activity of any of the other simples that compose one. | |
| From: Peter van Inwagen (Material Beings [1990], 15) | |
| A reaction: This justifies the common view that 'one follows one's brain'. I take that to mean that my brain embodies my essence. I would read 'centered on' as 'explains'. |
| 17573 | There is no reason to think that mere existence is a valuable thing [Inwagen] |
| Full Idea: There is no reason to suppose - whatever Saint Anselm and Descartes may have thought - that mere existence is a valuable thing. | |
| From: Peter van Inwagen (Material Beings [1990], 12) | |
| A reaction: This is one of the simplest and most powerful objections to the Ontological Argument. God's existence may be of great value, but the existence of Hitler wasn't. |