30 ideas
| 9226 | If mathematical theories conflict, it may just be that they have different subject matter [Field,H] |
| Full Idea: Unlike logic, in the case of mathematics there may be no genuine conflict between alternative theories: it is natural to think that different theories, if both consistent, are simply about different subjects. | |
| From: Hartry Field (Recent Debates on the A Priori [2005], 7) | |
| A reaction: For this reason Field places logic at the heart of questions about a priori knowledge, rather than mathematics. My intuitions make me doubt his proposal. Given the very simple basis of, say, arithmetic, I would expect all departments to connect. |
| 17518 | Counting 'coin in this box' may have coin as the unit, with 'in this box' merely as the scope [Ayers] |
| Full Idea: If we count the concept 'coin in this box', we could regard coin as the 'unit', while taking 'in this box' to limit the scope. Counting coins in two boxes would be not a difference in unit (kind of object), but in scope. | |
| From: M.R. Ayers (Individuals without Sortals [1974], 'Counting') | |
| A reaction: This is a very nice alternative to the Fregean view of counting, depending totally on the concept, and rests more on a natural concept of object. I prefer Ayers. Compare 'count coins till I tell you to stop'. |
| 17516 | If counting needs a sortal, what of things which fall under two sortals? [Ayers] |
| Full Idea: If we accepted that counting objects always presupposes some sortal, it is surely clear that the class of objects to be counted could be designated by two sortals rather than one. | |
| From: M.R. Ayers (Individuals without Sortals [1974], 'Realist' vii) | |
| A reaction: His nice example is an object which is both 'a single piece of wool' and a 'sweater', which had better not be counted twice. Wiggins struggles to argue that there is always one 'substance sortal' which predominates. |
| 17520 | Events do not have natural boundaries, and we have to set them [Ayers] |
| Full Idea: In order to know which event has been ostensively identified by a speaker, the auditor must know the limits intended by the speaker. ...Events do not have natural boundaries. | |
| From: M.R. Ayers (Individuals without Sortals [1974], 'Concl') | |
| A reaction: He distinguishes events thus from natural objects, where the world, to a large extent, offers us the boundaries. Nice point. |
| 17519 | To express borderline cases of objects, you need the concept of an 'object' [Ayers] |
| Full Idea: The only explanation of the power to produce borderline examples like 'Is this hazelnut one object or two?' is the possession of the concept of an object. | |
| From: M.R. Ayers (Individuals without Sortals [1974], 'Counting') |
| 17510 | Speakers need the very general category of a thing, if they are to think about it [Ayers] |
| Full Idea: If a speaker indicates something, then in order for others to catch his reference they must know, at some level of generality, what kind of thing is indicated. They must categorise it as event, object, or quality. Thinking about something needs that much. | |
| From: M.R. Ayers (Individuals without Sortals [1974], Intro) | |
| A reaction: Ayers defends the view that such general categories are required, but not the much narrower sortal terms defended by Geach and Wiggins. I'm with Ayers all the way. 'What the hell is that?' |
| 17522 | We use sortals to classify physical objects by the nature and origin of their unity [Ayers] |
| Full Idea: Sortals are the terms by which we intend to classify physical objects according to the nature and origin of their unity. | |
| From: M.R. Ayers (Individuals without Sortals [1974], 'Concl') | |
| A reaction: This is as opposed to using sortals for the initial individuation. I take the perception of the unity to come first, so resemblance must be mentioned, though it can be an underlying (essentialist) resemblance. |
| 17515 | Seeing caterpillar and moth as the same needs continuity, not identity of sortal concepts [Ayers] |
| Full Idea: It is unnecessary to call moths 'caterpillars' or caterpillars 'moths' to see that they can be the same individual. It may be that our sortal concepts reflect our beliefs about continuity, but our beliefs about continuity need not reflect our sortals. | |
| From: M.R. Ayers (Individuals without Sortals [1974], 'Realist' vi) | |
| A reaction: Something that metamorphosed through 15 different stages could hardly required 15 different sortals before we recognised the fact. Ayers is right. |
| 17511 | Recognising continuity is separate from sortals, and must precede their use [Ayers] |
| Full Idea: The recognition of the fact of continuity is logically independent of the possession of sortal concepts, whereas the formation of sortal concepts is at least psychologically dependent upon the recognition of continuity. | |
| From: M.R. Ayers (Individuals without Sortals [1974], Intro) | |
| A reaction: I take this to be entirely correct. I might add that unity must also be recognised. |
| 17517 | Could the same matter have more than one form or principle of unity? [Ayers] |
| Full Idea: The abstract question arises of whether the same matter could be subject to more than one principle of unity simultaneously, or unified by more than one 'form'. | |
| From: M.R. Ayers (Individuals without Sortals [1974], 'Realist' vii) | |
| A reaction: He suggests that the unity of the sweater is destroyed by unravelling, and the unity of the thread by cutting. |
| 17513 | If there are two objects, then 'that marble, man-shaped object' is ambiguous [Ayers] |
| Full Idea: The statue is marble and man-shaped, but so is the piece of marble. So not only are the two objects in the same place, but two marble and man-shaped objects in the same place, so 'that marble, man-shaped object' must be ambiguous or indefinite. | |
| From: M.R. Ayers (Individuals without Sortals [1974], 'Prob') | |
| A reaction: It strikes me as basic that it can't be a piece of marble if you subtract its shape, and it can't be a statue if you subtract its matter. To treat a statue as an object, separately from its matter, is absurd. |
| 17523 | Sortals basically apply to individuals [Ayers] |
| Full Idea: Sortals, in their primitive use, apply to the individual. | |
| From: M.R. Ayers (Individuals without Sortals [1974], 'Concl') | |
| A reaction: If the sortal applies to the individual, any essence must pertain to that individual, and not to the class it has been placed in. |
| 17521 | You can't have the concept of a 'stage' if you lack the concept of an object [Ayers] |
| Full Idea: It would be impossible for anyone to have the concept of a stage who did not already possess the concept of a physical object. | |
| From: M.R. Ayers (Individuals without Sortals [1974], 'Concl') |
| 17514 | Temporal 'parts' cannot be separated or rearranged [Ayers] |
| Full Idea: Temporally extended 'parts' are still mysteriously inseparable and not subject to rearrangement: a thing cannot be cut temporally in half. | |
| From: M.R. Ayers (Individuals without Sortals [1974], 'Prob') | |
| A reaction: A nice warning to anyone accepting a glib analogy between spatial parts and temporal parts. |
| 17509 | Some say a 'covering concept' completes identity; others place the concept in the reference [Ayers] |
| Full Idea: Some hold that the 'covering concept' completes the incomplete concept of identity, determining the kind of sameness involved. Others strongly deny the identity itself is incomplete, and locate the covering concept within the necessary act of reference. | |
| From: M.R. Ayers (Individuals without Sortals [1974], Intro) | |
| A reaction: [a bit compressed; Geach is the first view, and Quine the second; Wiggins is somewhere between the two] |
| 17512 | If diachronic identities need covering concepts, why not synchronic identities too? [Ayers] |
| Full Idea: Why are covering concepts required for diachronic identities, when they must be supposed unnecessary for synchronic identities? | |
| From: M.R. Ayers (Individuals without Sortals [1974], 'Prob') |
| 21202 | The strong force has a considerably greater range than the weak force [Martin,BR] |
| Full Idea: The strong nuclear force has a range of 10^-15 m, considerably larger than the range of the weak force. | |
| From: Brian R. Martin (Particle Physics [2011], 01) | |
| A reaction: This is because the bosons transmitting the weak force (W+, W-, W°) are much heavier than the gluons of the strong force. |
| 21211 | If an expected reaction does not occur, that implies a conservation law [Martin,BR] |
| Full Idea: If some reaction is not observed when there is apparently nothing to prevent it occurring, it is an indication that a conservation law is in operation. | |
| From: Brian R. Martin (Particle Physics [2011], 07) |
| 21209 | Electron emit and reabsorb photons, which create and reabsorb virtual electrons and positrons [Martin,BR] |
| Full Idea: In QED an electron constantly emits and reabsorbs virtual photons and these photons constantly create and reabsorb pairs of virtual electrons and positrons, and so on. | |
| From: Brian R. Martin (Particle Physics [2011], 06) | |
| A reaction: 'And so on'! These virtual particles have energy, and hence mass. |
| 21201 | A 'field' is just a region to which points can be assigned in space and time [Martin,BR] |
| Full Idea: The word 'field' is simply a shorthand way of saying that a physical property is assigned to the points of space and time in a region. | |
| From: Brian R. Martin (Particle Physics [2011], 01) | |
| A reaction: This is disappointing because I had begun to think that fields were foundational for modern ontology. Turns out they are operational abstractions (according to Martin). Note that a field extends over time. |
| 21212 | The Higgs field, unlike others, has a nozero value in a state without particles [Martin,BR] |
| Full Idea: The Higgs field has the property of having a nonzero value in a state without particles, the vacuum state. Other fields are assumed to have a value zero in a vacuum state. | |
| From: Brian R. Martin (Particle Physics [2011], 09) | |
| A reaction: This seems to make a big difference to our concept of a field, since it has a measurable reality even when there are no particles. So it isn't just a geometrical frame for locating particles. |
| 21205 | Many physicists believe particles have further structure, if only we could see it [Martin,BR] |
| Full Idea: Although standard particles are assumed to be structureless, many physicists believe that if distances could be probed down to 10^-35 m structures would be discovered. | |
| From: Brian R. Martin (Particle Physics [2011], 01) | |
| A reaction: Such probing is said to be probably impossible. And does the division then come to a halt? Aristotle's meditations on this are not irrelevant. |
| 21203 | Uncertainty allows very brief violations of energy conservation - even shorter with higher energies [Martin,BR] |
| Full Idea: The uncertainty principle states that energy conservation can be violated, but only for a limited period of time. As the energy violation increases, the time period within which 'borrowed' energy has to be 'paid back' decreases. | |
| From: Brian R. Martin (Particle Physics [2011], 01) | |
| A reaction: This is the only reason modern physicists ever seem to mention the uncertainty principle. You can ask why this debt must be paid, but it seems to be hidden where the laws of physics may not even apply. |
| 21207 | The Exclusion Principle says no two fermions occupy the same state, with the same numbers [Martin,BR] |
| Full Idea: The 'exclusion principle' initially stated that no two electrons in a system could simultaneously occupy the same quantum state and thus have the same set of quantum numbers. The principle actually applies to all fermions, but not to bosons. | |
| From: Brian R. Martin (Particle Physics [2011], 02) | |
| A reaction: This principle is said to be at the root of atomic structure, making each element unique. What exactly is a 'system'? Why does this principle hold? How do you ensure two women don't wear the same dress at a party? |
| 21204 | The standard model combines theories of strong interaction, and electromagnetic and weak interaction [Martin,BR] |
| Full Idea: As presently formulated, the standard model is two theories. One operates in the sector of strong interaction, and the other in the sector of the electromagnetic and weak interactions. | |
| From: Brian R. Martin (Particle Physics [2011], 01) | |
| A reaction: The first is Quantum Chomodynamics (QCD). The second is Quantum Electrodynamics (QED). Interesting that the weak interaction is included in the latter, which (I take it) means there is an electro-weak union. Interactions are the heart of the model. |
| 21208 | Eletrons don't literally 'spin', because they are point-like [Martin,BR] |
| Full Idea: The picture of a particle spinning like a top is sometime useful, but it is not consistent with the idea of the electron being point-like. In fact there is no analogy for spin in non-quantum physics. | |
| From: Brian R. Martin (Particle Physics [2011], 02) | |
| A reaction: If we take this stuff literally then it blow traditional metaphysics to bits, because an electron has properties without being a substance. In what sense can an electron 'have' properties if it is a point? In interactions they cease to be points. Eh? |
| 21210 | Virtual particles surround any charged particle [Martin,BR] |
| Full Idea: A cloud of virtual particles always surrounds a charged particle. | |
| From: Brian R. Martin (Particle Physics [2011], 06) | |
| A reaction: Here's a nice fact for aspiring Buddhists to meditate on. |
| 21206 | The properties of a particle are determined by its quantum numbers and its mass [Martin,BR] |
| Full Idea: In quantum theory, the full set of quantum numbers defines the state of the particle and, along with its mass, determines its properties. | |
| From: Brian R. Martin (Particle Physics [2011], 02) |
| 21213 | String theory only has one free parameter (tension) - unlike the standard model with 19 [Martin,BR] |
| Full Idea: Unlike the standard model, with its 19 free parameters (including the masses of quarks, coupling constants and mixing angles), string theories have a single free paramater: the string tension. | |
| From: Brian R. Martin (Particle Physics [2011], 10) | |
| A reaction: This must be one feature in favour of string theory, despite its problems. |
| 21200 | An 'element' is what cannot be decomposed by chemistry [Martin,BR] |
| Full Idea: In the modern sense 'element' means a substance that cannot be decomposed by the methods of chemistry. | |
| From: Brian R. Martin (Particle Physics [2011], 01) |