38 ideas
| 8472 | Sentential logic is consistent (no contradictions) and complete (entirely provable) [Orenstein] |
| Full Idea: Sentential logic has been proved consistent and complete; its consistency means that no contradictions can be derived, and its completeness assures us that every one of the logical truths can be proved. | |
| From: Alex Orenstein (W.V. Quine [2002], Ch.5) | |
| A reaction: The situation for quantificational logic is not quite so clear (Orenstein p.98). I do not presume that being consistent and complete makes it necessarily better as a tool in the real world. |
| 8476 | Axiomatization simply picks from among the true sentences a few to play a special role [Orenstein] |
| Full Idea: In axiomatizing, we are merely sorting out among the truths of a science those which will play a special role, namely, serve as axioms from which we derive the others. The sentences are already true in a non-conventional or ordinary sense. | |
| From: Alex Orenstein (W.V. Quine [2002], Ch.5) | |
| A reaction: If you were starting from scratch, as Euclidean geometers may have felt they were doing, you might want to decide which are the simplest truths. Axiomatizing an established system is a more advanced activity. |
| 8480 | S4: 'poss that poss that p' implies 'poss that p'; S5: 'poss that nec that p' implies 'nec that p' [Orenstein] |
| Full Idea: The five systems of propositional modal logic contain successively stronger conceptions of necessity. In S4 'it is poss that it is poss that p' implies 'it is poss that p'. In S5, 'it is poss that it is nec that p' implies 'it is nec that p'. | |
| From: Alex Orenstein (W.V. Quine [2002], Ch.7) | |
| A reaction: C.I. Lewis originated this stuff. Any serious student of modality is probably going to have to pick a system. E.g. Nathan Salmon says that the correct modal logic is even weaker than S4. |
| 8474 | Unlike elementary logic, set theory is not complete [Orenstein] |
| Full Idea: The incompleteness of set theory contrasts sharply with the completeness of elementary logic. | |
| From: Alex Orenstein (W.V. Quine [2002], Ch.5) | |
| A reaction: This seems to be Quine's reason for abandoning the Frege-Russell logicist programme (quite apart from the problems raised by Gödel. |
| 8465 | Mereology has been exploited by some nominalists to achieve the effects of set theory [Orenstein] |
| Full Idea: The theory of mereology has had a history of being exploited by nominalists to achieve some of the effects of set theory. | |
| From: Alex Orenstein (W.V. Quine [2002], Ch.3) | |
| A reaction: Some writers refer to mereology as a 'theory', and others as an area of study. This appears to be an interesting line of investigation. Orenstein says Quine and Goodman showed its limitations. |
| 8452 | Traditionally, universal sentences had existential import, but were later treated as conditional claims [Orenstein] |
| Full Idea: In traditional logic from Aristotle to Kant, universal sentences have existential import, but Brentano and Boole construed them as universal conditionals (such as 'for anything, if it is a man, then it is mortal'). | |
| From: Alex Orenstein (W.V. Quine [2002], Ch.2) | |
| A reaction: I am sympathetic to the idea that even the 'existential' quantifier should be treated as conditional, or fictional. Modern Christians may well routinely quantify over angels, without actually being committed to them. |
| 8475 | The substitution view of quantification says a sentence is true when there is a substitution instance [Orenstein] |
| Full Idea: The substitution view of quantification explains 'there-is-an-x-such-that x is a man' as true when it has a true substitution instance, as in the case of 'Socrates is a man', so the quantifier can be read as 'it is sometimes true that'. | |
| From: Alex Orenstein (W.V. Quine [2002], Ch.5) | |
| A reaction: The word 'true' crops up twice here. The alternative (existential-referential) view cites objects, so the substitution view is a more linguistic approach. |
| 8454 | The whole numbers are 'natural'; 'rational' numbers include fractions; the 'reals' include root-2 etc. [Orenstein] |
| Full Idea: The 'natural' numbers are the whole numbers 1, 2, 3 and so on. The 'rational' numbers consist of the natural numbers plus the fractions. The 'real' numbers include the others, plus numbers such a pi and root-2, which cannot be expressed as fractions. | |
| From: Alex Orenstein (W.V. Quine [2002], Ch.2) | |
| A reaction: The 'irrational' numbers involved entities such as root-minus-1. Philosophical discussions in ontology tend to focus on the existence of the real numbers. |
| 8473 | The logicists held that is-a-member-of is a logical constant, making set theory part of logic [Orenstein] |
| Full Idea: The question to be posed is whether is-a-member-of should be considered a logical constant, that is, does logic include set theory. Frege, Russell and Whitehead held that it did. | |
| From: Alex Orenstein (W.V. Quine [2002], Ch.5) | |
| A reaction: This is obviously the key element in the logicist programme. The objection seems to be that while first-order logic is consistent and complete, set theory is not at all like that, and so is part of a different world. |
| 16062 | A necessary relation between fact-levels seems to be a further irreducible fact [Lynch/Glasgow] |
| Full Idea: It seems unavoidable that the facts about logically necessary relations between levels of facts are themselves logically distinct further facts, irreducible to the microphysical facts. | |
| From: Lynch,MP/Glasgow,JM (The Impossibility of Superdupervenience [2003], C) | |
| A reaction: I'm beginning to think that rejecting every theory of reality that is proposed by carefully exposing some infinite regress hidden in it is a rather lazy way to do philosophy. Almost as bad as rejecting anything if it can't be defined. |
| 16061 | If some facts 'logically supervene' on some others, they just redescribe them, adding nothing [Lynch/Glasgow] |
| Full Idea: Logical supervenience, restricted to individuals, seems to imply strong reduction. It is said that where the B-facts logically supervene on the A-facts, the B-facts simply re-describe what the A-facts describe, and the B-facts come along 'for free'. | |
| From: Lynch,MP/Glasgow,JM (The Impossibility of Superdupervenience [2003], C) | |
| A reaction: This seems to be taking 'logically' to mean 'analytically'. Presumably an entailment is logically supervenient on its premisses, and may therefore be very revealing, even if some people think such things are analytic. |
| 16060 | Nonreductive materialism says upper 'levels' depend on lower, but don't 'reduce' [Lynch/Glasgow] |
| Full Idea: The root intuition behind nonreductive materialism is that reality is composed of ontologically distinct layers or levels. …The upper levels depend on the physical without reducing to it. | |
| From: Lynch,MP/Glasgow,JM (The Impossibility of Superdupervenience [2003], B) | |
| A reaction: A nice clear statement of a view which I take to be false. This relationship is the sort of thing that drives people fishing for an account of it to use the word 'supervenience', which just says two things seem to hang out together. Fluffy materialism. |
| 16064 | The hallmark of physicalism is that each causal power has a base causal power under it [Lynch/Glasgow] |
| Full Idea: Jessica Wilson (1999) says what makes physicalist accounts different from emergentism etc. is that each individual causal power associated with a supervenient property is numerically identical with a causal power associated with its base property. | |
| From: Lynch,MP/Glasgow,JM (The Impossibility of Superdupervenience [2003], n 11) | |
| A reaction: Hence the key thought in so-called (serious, rather than self-evident) 'emergentism' is so-called 'downward causation', which I take to be an idle daydream. |
| 8458 | Just individuals in Nominalism; add sets for Extensionalism; add properties, concepts etc for Intensionalism [Orenstein] |
| Full Idea: Modest ontologies are Nominalism (Goodman), admitting only concrete individuals; and Extensionalism (Quine/Davidson) which admits individuals and sets; but Intensionalists (Frege/Carnap/Church/Marcus/Kripke) may have propositions, properties, concepts. | |
| From: Alex Orenstein (W.V. Quine [2002], Ch.3) | |
| A reaction: I don't like sets, because of Idea 7035. Even the ontology of individuals could collapse dramatically (see the ideas of Merricks, e.g. 6124). The intensional items may be real enough, but needn't have a place at the ontological high table. |
| 8457 | The Principle of Conservatism says we should violate the minimum number of background beliefs [Orenstein] |
| Full Idea: The principle of conservatism in choosing between theories is a maxim of minimal mutilation, stating that of competing theories, all other things being equal, choose the one that violates the fewest background beliefs held. | |
| From: Alex Orenstein (W.V. Quine [2002], Ch.2) | |
| A reaction: In this sense, all rational people should be conservatives. The idea is a modern variant of Hume's objection to miracles (Idea 2227). A Kuhnian 'paradigm shift' is the dramatic moment when this principle no longer seems appropriate. |
| 8477 | People presume meanings exist because they confuse meaning and reference [Orenstein] |
| Full Idea: A good part of the confidence people have that there are meanings rests on the confusion of meaning and reference. | |
| From: Alex Orenstein (W.V. Quine [2002], Ch.6) | |
| A reaction: An important point. Everyone assumes that sentences link to the world, but Frege shows that that is not part of meaning. Words like prepositions and conjunctions ('to', 'and') don't have 'a meaning' apart from their function and use. |
| 8471 | Three ways for 'Socrates is human' to be true are nominalist, platonist, or Montague's way [Orenstein] |
| Full Idea: 'Socrates is human' is true if 1) subject referent is identical with a predicate referent (Nominalism), 2) subject reference member of the predicate set, or the subject has that property (Platonism), 3) predicate set a member of the subject set (Montague) | |
| From: Alex Orenstein (W.V. Quine [2002], Ch.3) | |
| A reaction: Orenstein offers these as alternatives to Quine's 'inscrutability of reference' thesis, which makes the sense unanalysable. |
| 8484 | If two people believe the same proposition, this implies the existence of propositions [Orenstein] |
| Full Idea: If we can say 'there exists a p such that John believes p and Barbara believes p', logical forms such as this are cited as evidence for our ontological commitment to propositions. | |
| From: Alex Orenstein (W.V. Quine [2002], Ch.7) | |
| A reaction: Opponents of propositions (such as Quine) will, of course, attempt to revise the logical form to eliminate the quantification over propositions. See Orenstein's outline on p.171. |
| 21181 | Relativity and Quantum theory give very different accounts of forces [Hesketh] |
| Full Idea: General Relativity and quantum mechanics are the two great theories in physics today but they give two very different ideas for how forces work. | |
| From: Gavin Hesketh (The Particle Zoo [2016], 01) | |
| A reaction: Relativity says it is space curvature, and quantum theory says it is particle exchange? But is there a Relativity account of the strong nuclear force? |
| 21183 | Thermodynamics introduced work and entropy, to understand steam engine efficiency [Hesketh] |
| Full Idea: The Laws of Thermodynamics introduced the concepts of entropy and work; put simply, how much useful energy you can really get out of a steam engine. | |
| From: Gavin Hesketh (The Particle Zoo [2016], 03) | |
| A reaction: The point of science by this stage was to introduce measurable and quantifiable concepts |
| 21191 | Photons are B and W° bosons, linked by the Higgs mechanism [Hesketh] |
| Full Idea: The photon is actually a mix of two deeper things, the B and the W°, tied together by the Higgs mechanism. | |
| From: Gavin Hesketh (The Particle Zoo [2016], 06) | |
| A reaction: The B (for 'Boson') transmits a force associated with the 'winding symmetry'. (I record this without properly understanding it.) |
| 21199 | Spinning electric charge produces magnetism, so all fermions are magnets [Hesketh] |
| Full Idea: The muon, like all fermions, spins - and because a spinning electric charge generates a magnetic field all fermions act like tiny bar magnets. | |
| From: Gavin Hesketh (The Particle Zoo [2016], 11) |
| 21180 | Electrons are fundamental and are not made of anything; they are properties without size [Hesketh] |
| Full Idea: As far as we can tell, electrons (and quarks) are fundamental. They are not small lumps of material, because we could always ask what the material is. The electron just ...is. They are collections of properties, with no apparent size. | |
| From: Gavin Hesketh (The Particle Zoo [2016], 01) | |
| A reaction: This idea from physics HAS to be of interest to philosophers! The bundle theory is discredited for normal objects and for minds, and so is the substrate idea for supporting properties. But rigorous physics accepts a bundle theory. |
| 21189 | Electrons may have smaller components, bound by a new force [Hesketh] |
| Full Idea: Quarks, leptons or bosons may actually be made up of something even smaller, bound together by a conjectural new force. | |
| From: Gavin Hesketh (The Particle Zoo [2016], 05) | |
| A reaction: Electrons are a type of lepton. Compare Idea 21180, from the same book. If electrons are not fundamental, what matters is not some 'stuff' they are made of, but a different force that would bind the ingredients. |
| 21184 | Physics was rewritten to explain stable electron orbits [Hesketh] |
| Full Idea: Explaining the stable electron orbits would require a complete rewriting of the physics of subatomic particles. | |
| From: Gavin Hesketh (The Particle Zoo [2016], 03) | |
| A reaction: This really looks like a simple and major landmark moment. You can ignore a single anomaly, but not a central feature of your entire theory. |
| 21182 | Quantum mechanics is our only theory, and is very precise, and repeatedly confirmed [Hesketh] |
| Full Idea: Quantum mechanics is the only working description of the universe that we have. It is amazingly precise, and so far every experimental test has verified its predictions. | |
| From: Gavin Hesketh (The Particle Zoo [2016], 02) | |
| A reaction: I take it from this that quantum mechanics is simply TRUE. Get over it! It will never turn out to be wrong, but may be subsumed within some more fine-grained or extensive theory. |
| 21187 | Virtual particles can't be measured, and can ignore the laws of physics [Hesketh] |
| Full Idea: We can never measure these virtual (transitory) particles directly, and it turns out that they don't even have to obey the laws of physics. | |
| From: Gavin Hesketh (The Particle Zoo [2016], 05) | |
| A reaction: These seems to be the real significance of the Uncertainty Principle. Such particles 'borrow' huge amounts of energy for very short times. |
| 21185 | Colour charge is positive or negative, and also has red, green or blue direction [Hesketh] |
| Full Idea: Colour charge is 'three-dimensional'. As well as the charge having a positive or negative sign, it can also have a direction, and for convenience these three different directions (pointing like a weather vane) are labelled 'red', 'green' and 'blue'. | |
| From: Gavin Hesketh (The Particle Zoo [2016], 04) |
| 21195 | In Supersymmetry the Standard Model simplifies at high energies [Hesketh] |
| Full Idea: Supersymmetry suggest that the Standard Model becomes much simpler at high energies. | |
| From: Gavin Hesketh (The Particle Zoo [2016], 10) |
| 21194 | The Standard Model omits gravity, because there are no particles involved [Hesketh] |
| Full Idea: Gravity is not included in the Standard Model because we simply cannot study it using particles. | |
| From: Gavin Hesketh (The Particle Zoo [2016], 09) | |
| A reaction: I'm guessing that Einstein describes how gravity behaves, but not what it is. |
| 21197 | Standard Model forces are one- two- and three-dimensional [Hesketh] |
| Full Idea: The forces in the Standard Model are built on gauge symmetries, with a one-dimensional charge (like electromagnetism), a two-dimensional charge (the weak force), and a three dimensional charge (the strong force). | |
| From: Gavin Hesketh (The Particle Zoo [2016], 10) | |
| A reaction: See also Idea 21185. |
| 21188 | Quarks and leptons have a weak charge, for the weak force [Hesketh] |
| Full Idea: For the weak force there must be a corresponding 'weak charge', and all the fermions, all the quarks and leptons carry it. | |
| From: Gavin Hesketh (The Particle Zoo [2016], 05) | |
| A reaction: So electrons carry a weak charge, as well as an electromagnetic charge. Like owning several passports. |
| 21186 | Quarks rush wildly around in protons, restrained by the gluons [Hesketh] |
| Full Idea: Inside a proton the quarks are rushing around like caged animals, free to move until they push against the bars to try to escape, when the gluons pull them back in. | |
| From: Gavin Hesketh (The Particle Zoo [2016], 04) |
| 21192 | Neutrinos only interact with the weak force, but decays produce them in huge numbers [Hesketh] |
| Full Idea: Neutrinos only interact with the weak force, which means they barely interact at all, but because the weak force is crucial in the decays of so many other particles, neutrinos are still produced in huge numbers. | |
| From: Gavin Hesketh (The Particle Zoo [2016], 08) | |
| A reaction: They only interact with the W and Z bosons. |
| 21196 | To combine the forces, they must all be the same strength at some point [Hesketh] |
| Full Idea: If all the forces are to combine, at some point they must all be the same strength, and Supersymmetry (SuSy) makes this happen. | |
| From: Gavin Hesketh (The Particle Zoo [2016], 10) | |
| A reaction: This sounds like an impressive reason for favouring supersymmetry - as long as you have an a priori preference for everything combining. |
| 21190 | 'Space' in physics just means location [Hesketh] |
| Full Idea: 'Space' in physics really just means location. | |
| From: Gavin Hesketh (The Particle Zoo [2016], 06) | |
| A reaction: Location can, of course, only be specified relative to something else. Space is really an abstraction, but at least it means there is some sort of background to locate all the fundamental fields. |
| 21193 | The universe is 68% dark energy, 27% dark matter, 5% regular matter [Hesketh] |
| Full Idea: The most precise surveys of the stars and galaxies tell us that the universe is made up of 68% dark energy, 27% dark matter, and just 5% regular matter (the stuff of the Standard Model of particle physics). | |
| From: Gavin Hesketh (The Particle Zoo [2016], 09) | |
| A reaction: Regular matter - that's me, that is. |
| 21198 | If a cosmic theory relies a great deal on fine-tuning basic values, it is probably wrong [Hesketh] |
| Full Idea: If a theory has to rely on excessive 'fine-tuning', a series of extremely unlikely events in order to produce the universe we see around us, then it is extremely unlikely that this theory is correct. | |
| From: Gavin Hesketh (The Particle Zoo [2016], 10) | |
| A reaction: He says the Standard Model has 26 parameters which are only known by experiment, rather than by theory. So instead of saying '...so there is a God', we should say '...so our theory isn't very good'. |