73 ideas
| 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. |
| 15413 | With four tense operators, all complex tenses reduce to fourteen basic cases [Burgess] |
| Full Idea: Fand P as 'will' and 'was', G as 'always going to be', H as 'always has been', all tenses reduce to 14 cases: the past series, each implying the next, FH,H,PH,HP,P,GP, and the future series PG,G,FG,GF,F,HF, plus GH=HG implying all, FP=PF which all imply. | |
| From: John P. Burgess (Philosophical Logic [2009], 2.8) | |
| A reaction: I have tried to translate the fourteen into English, but am not quite confident enough to publish them here. I leave it as an exercise for the reader. |
| 15415 | The temporal Barcan formulas fix what exists, which seems absurd [Burgess] |
| Full Idea: In temporal logic, if the converse Barcan formula holds then nothing goes out of existence, and the direct Barcan formula holds if nothing ever comes into existence. These results highlight the intuitive absurdity of the Barcan formulas. | |
| From: John P. Burgess (Philosophical Logic [2009], 2.9) | |
| A reaction: This is my reaction to the modal cases as well - the absurdity of thinking that no actually nonexistent thing might possibly have existed, or that the actual existents might not have existed. Williamson seems to be the biggest friend of the formulas. |
| 15430 | Is classical logic a part of intuitionist logic, or vice versa? [Burgess] |
| Full Idea: From one point of view intuitionistic logic is a part of classical logic, missing one axiom, from another classical logic is a part of intuitionistic logic, missing two connectives, intuitionistic v and → | |
| From: John P. Burgess (Philosophical Logic [2009], 6.4) |
| 15431 | It is still unsettled whether standard intuitionist logic is complete [Burgess] |
| Full Idea: The question of the completeness of the full intuitionistic logic for its intended interpretation is not yet fully resolved. | |
| From: John P. Burgess (Philosophical Logic [2009], 6.9) |
| 15429 | Relevance logic's → is perhaps expressible by 'if A, then B, for that reason' [Burgess] |
| Full Idea: The relevantist logician's → is perhaps expressible by 'if A, then B, for that reason'. | |
| From: John P. Burgess (Philosophical Logic [2009], 5.8) |
| 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). |
| 15404 | Technical people see logic as any formal system that can be studied, not a study of argument validity [Burgess] |
| Full Idea: Among the more technically oriented a 'logic' no longer means a theory about which forms of argument are valid, but rather means any formalism, regardless of its applications, that resembles original logic enough to be studied by similar methods. | |
| From: John P. Burgess (Philosophical Logic [2009], Pref) | |
| A reaction: There doesn't seem to be any great intellectual obligation to be 'technical'. As far as pure logic is concerned, I am very drawn to the computer approach, since I take that to be the original dream of Aristotle and Leibniz - impersonal precision. |
| 15405 | Classical logic neglects the non-mathematical, such as temporality or modality [Burgess] |
| Full Idea: There are topics of great philosophical interest that classical logic neglects because they are not important to mathematics. …These include distinctions of past, present and future, or of necessary, actual and possible. | |
| From: John P. Burgess (Philosophical Logic [2009], 1.1) |
| 15427 | The Cut Rule expresses the classical idea that entailment is transitive [Burgess] |
| Full Idea: The Cut rule (from A|-B and B|-C, infer A|-C) directly expresses the classical doctrine that entailment is transitive. | |
| From: John P. Burgess (Philosophical Logic [2009], 5.3) |
| 15421 | Classical logic neglects counterfactuals, temporality and modality, because maths doesn't use them [Burgess] |
| Full Idea: Classical logic neglects counterfactual conditionals for the same reason it neglects temporal and modal distinctions, namely, that they play no serious role in mathematics. | |
| From: John P. Burgess (Philosophical Logic [2009], 4.1) | |
| A reaction: Science obviously needs counterfactuals, and metaphysics needs modality. Maybe so-called 'classical' logic will be renamed 'basic mathematical logic'. Philosophy will become a lot clearer when that happens. |
| 15403 | Philosophical logic is a branch of logic, and is now centred in computer science [Burgess] |
| Full Idea: Philosophical logic is a branch of logic, a technical subject. …Its centre of gravity today lies in theoretical computer science. | |
| From: John P. Burgess (Philosophical Logic [2009], Pref) | |
| A reaction: He firmly distinguishes it from 'philosophy of logic', but doesn't spell it out. I take it that philosophical logic concerns metaprinciples which compare logical systems, and suggest new lines of research. Philosophy of logic seems more like metaphysics. |
| 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'. |
| 15407 | Formalising arguments favours lots of connectives; proving things favours having very few [Burgess] |
| Full Idea: When formalising arguments it is convenient to have as many connectives as possible available.; but when proving results about formulas it is convenient to have as few as possible. | |
| From: John P. Burgess (Philosophical Logic [2009], 1.4) | |
| A reaction: Illuminating. The fact that you can whittle classical logic down to two (or even fewer!) connectives warms the heart of technicians, but makes connection to real life much more difficult. Hence a bunch of extras get added. |
| 15424 | Asserting a disjunction from one disjunct seems odd, but can be sensible, and needed in maths [Burgess] |
| Full Idea: Gricean implicature theory might suggest that a disjunction is never assertable when a disjunct is (though actually the disjunction might be 'pertinent') - but the procedure is indispensable in mathematical practice. | |
| From: John P. Burgess (Philosophical Logic [2009], 5.2) | |
| A reaction: He gives an example of a proof in maths which needs it, and an unusual conversational occasion where it makes sense. |
| 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. |
| 15409 | All occurrences of variables in atomic formulas are free [Burgess] |
| Full Idea: All occurrences of variables in atomic formulas are free. | |
| From: John P. Burgess (Philosophical Logic [2009], 1.7) |
| 15414 | The denotation of a definite description is flexible, rather than rigid [Burgess] |
| Full Idea: By contrast to rigidly designating proper names, …the denotation of definite descriptions is (in general) not rigid but flexible. | |
| From: John P. Burgess (Philosophical Logic [2009], 2.9) | |
| A reaction: This modern way of putting it greatly clarifies why Russell was interested in the type of reference involved in definite descriptions. Obviously some descriptions (such as 'the only person who could ever have…') might be rigid. |
| 15406 | 'Induction' and 'recursion' on complexity prove by connecting a formula to its atomic components [Burgess] |
| Full Idea: There are atomic formulas, and formulas built from the connectives, and that is all. We show that all formulas have some property, first for the atomics, then the others. This proof is 'induction on complexity'; we also use 'recursion on complexity'. | |
| From: John P. Burgess (Philosophical Logic [2009], 1.4) | |
| A reaction: That is: 'induction on complexity' builds a proof from atomics, via connectives; 'recursion on complexity' breaks down to the atomics, also via the connectives. You prove something by showing it is rooted in simple truths. |
| 15425 | The sequent calculus makes it possible to have proof without transitivity of entailment [Burgess] |
| Full Idea: It might be wondered how one could have any kind of proof procedure at all if transitivity of entailment is disallowed, but the sequent calculus can get around the difficulty. | |
| From: John P. Burgess (Philosophical Logic [2009], 5.3) | |
| A reaction: He gives examples where transitivity of entailment (so that you can build endless chains of deductions) might fail. This is the point of the 'cut free' version of sequent calculus, since the cut rule allows transitivity. |
| 15426 | We can build one expanding sequence, instead of a chain of deductions [Burgess] |
| Full Idea: Instead of demonstrations which are either axioms, or follow from axioms by rules, we can have one ever-growing sequence of formulas of the form 'Axioms |- ______', where the blank is filled by Axioms, then Lemmas, then Theorems, then Corollaries. | |
| From: John P. Burgess (Philosophical Logic [2009], 5.3) |
| 15408 | 'Tautologies' are valid formulas of classical sentential logic - or substitution instances in other logics [Burgess] |
| Full Idea: The valid formulas of classical sentential logic are called 'tautologically valid', or simply 'tautologies'; with other logics 'tautologies' are formulas that are substitution instances of valid formulas of classical sentential logic. | |
| From: John P. Burgess (Philosophical Logic [2009], 1.5) |
| 15418 | Validity (for truth) and demonstrability (for proof) have correlates in satisfiability and consistency [Burgess] |
| Full Idea: Validity (truth by virtue of logical form alone) and demonstrability (provability by virtue of logical form alone) have correlative notions of logical possibility, 'satisfiability' and 'consistency', which come apart in some logics. | |
| From: John P. Burgess (Philosophical Logic [2009], 3.3) |
| 15412 | Models leave out meaning, and just focus on truth values [Burgess] |
| Full Idea: Models generally deliberately leave out meaning, retaining only what is important for the determination of truth values. | |
| From: John P. Burgess (Philosophical Logic [2009], 2.2) | |
| A reaction: This is the key point to hang on to, if you are to avoid confusing mathematical models with models of things in the real world. |
| 15411 | We only need to study mathematical models, since all other models are isomorphic to these [Burgess] |
| Full Idea: In practice there is no need to consider any but mathematical models, models whose universes consist of mathematical objects, since every model is isomorphic to one of these. | |
| From: John P. Burgess (Philosophical Logic [2009], 1.8) | |
| A reaction: The crucial link is the technique of Gödel Numbering, which can translate any verbal formula into numerical form. He adds that, because of the Löwenheim-Skolem theorem only subsets of the natural numbers need be considered. |
| 15416 | We aim to get the technical notion of truth in all models matching intuitive truth in all instances [Burgess] |
| Full Idea: The aim in setting up a model theory is that the technical notion of truth in all models should agree with the intuitive notion of truth in all instances. A model is supposed to represent everything about an instance that matters for its truth. | |
| From: John P. Burgess (Philosophical Logic [2009], 3.2) |
| 15428 | The Liar seems like a truth-value 'gap', but dialethists see it as a 'glut' [Burgess] |
| Full Idea: It is a common view that the liar sentence ('This very sentence is not true') is an instance of a truth-value gap (neither true nor false), but some dialethists cite it as an example of a truth-value glut (both true and false). | |
| From: John P. Burgess (Philosophical Logic [2009], 5.7) | |
| A reaction: The defence of the glut view must be that it is true, then it is false, then it is true... Could it manage both at once? |
| 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) |
| 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. |
| 15420 | De re modality seems to apply to objects a concept intended for sentences [Burgess] |
| Full Idea: There is a problem over 'de re' modality (as contrasted with 'de dicto'), as in ∃x□x. What is meant by '"it is analytic that Px" is satisfied by a', given that analyticity is a notion that in the first instance applies to complete sentences? | |
| From: John P. Burgess (Philosophical Logic [2009], 3.9) | |
| A reaction: This is Burgess's summary of one of Quine's original objections. The issue may be a distinction between whether the sentence is analytic, and what makes it analytic. The necessity of bachelors being unmarried makes that sentence analytic. |
| 15419 | General consensus is S5 for logical modality of validity, and S4 for proof [Burgess] |
| Full Idea: To the extent that there is any conventional wisdom about the question, it is that S5 is correct for alethic logical modality, and S4 correct for apodictic logical modality. | |
| From: John P. Burgess (Philosophical Logic [2009], 3.8) | |
| A reaction: In classical logic these coincide, so presumably one should use the minimum system to do the job, which is S4 (?). |
| 15417 | Logical necessity has two sides - validity and demonstrability - which coincide in classical logic [Burgess] |
| Full Idea: Logical necessity is a genus with two species. For classical logic the truth-related notion of validity and the proof-related notion of demonstrability, coincide - but they are distinct concept. In some logics they come apart, in intension and extension. | |
| From: John P. Burgess (Philosophical Logic [2009], 3.3) | |
| A reaction: They coincide in classical logic because it is sound and complete. This strikes me as the correct approach to logical necessity, tying it to the actual nature of logic, rather than some handwavy notion of just 'true in all possible worlds'. |
| 15422 | Three conditionals theories: Materialism (material conditional), Idealism (true=assertable), Nihilism (no truth) [Burgess] |
| Full Idea: Three main theories of the truth of indicative conditionals are Materialism (the conditions are the same as for the material conditional), Idealism (identifying assertability with truth-value), and Nihilism (no truth, just assertability). | |
| From: John P. Burgess (Philosophical Logic [2009], 4.3) |
| 15423 | It is doubtful whether the negation of a conditional has any clear meaning [Burgess] |
| Full Idea: It is contentious whether conditionals have negations, and whether 'it is not the case that if A,B' has any clear meaning. | |
| From: John P. Burgess (Philosophical Logic [2009], 4.9) | |
| A reaction: This seems to be connected to Lewis's proof that a probability conditional cannot be reduced to a single proposition. If a conditional only applies to A-worlds, it is not surprising that its meaning gets lost when it leaves that world. |
| 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) |
| 541 | Virtue comes more from habit than character [Critias] |
| Full Idea: More men are good through habit than through character. | |
| From: Critias (fragments/reports [c.440 BCE], B09), quoted by John Stobaeus - Anthology 3.29.41 |
| 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. |
| 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'. |
| 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. |
| 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. |
| 542 | Fear of the gods was invented to discourage secret sin [Critias] |
| Full Idea: When the laws forbade men to commit open crimes of violence, and they began to do them in secret, a wise and clever man invented fear of the gods for mortals, to frighten the wicked, even if they sin in secret. | |
| From: Critias (fragments/reports [c.440 BCE], B25), quoted by Sextus Empiricus - Against the Professors (six books) 9.54 |