24 ideas
| 13931 | By using aporiai as his start, Aristotle can defer to the wise, as well as to the many [Haslanger] |
| Full Idea: The Aristotelian method of working form aporia allows one to use as starting points not only what is said by 'the many', but also what is said by 'the wise', including philosophers. | |
| From: Sally Haslanger (Persistence, Change and Explanation [1989], 1 n2) | |
| A reaction: [She mentions Nussbaum 1986:ch 7 for the opposing view] I like this thought a lot. Aristotle's democratic respect for widespread views can be a bit puzzling sometimes. |
| 8978 | Events are made of other things, and are not fundamental to ontology [Bennett] |
| Full Idea: Events are not basic items in the universe; they should not be included in any fundamental ontology...all the truths about them are entailed by and explained and made true by truths that do not involve the event concept. | |
| From: Jonathan Bennett (Events and Their Names [1988], p.12), quoted by Peter Simons - Events 3.1 | |
| A reaction: Given the variable time spans of events, their ability to coincide, their ability to contain no motion, their blatantly conventional component, and their recalcitrance to individuation, I say Bennett is right. |
| 13925 | Ontology disputes rest on more basic explanation disputes [Haslanger] |
| Full Idea: Disputes over ontology derive from more fundamental disputes over forms of explanation. | |
| From: Sally Haslanger (Persistence, Change and Explanation [1989], 1) | |
| A reaction: It immediately strikes me that Haslanger has stolen my master idea, but unfortunately the dating suggests that she has priority. The tricky part is to combine this view with realism. |
| 13924 | The persistence of objects seems to be needed if the past is to explain the present [Haslanger] |
| Full Idea: The notion that things persist through change is deeply embedded in ideas we have about explanation, and in particular, in the idea that the present is constrained by the past. | |
| From: Sally Haslanger (Persistence, Change and Explanation [1989], 1) | |
| A reaction: I take this to be both an important and an attractive idea. Deniers of persistence (4D-ists) will presumably have some ability to explain the present, but it is the idea of the present being 'constrained' by the past which is a challenge. |
| 13930 | Persistence makes change and its products intelligible [Haslanger] |
| Full Idea: Persistence offers intelligibility: the possibility of understanding a change, and of understanding the products of it. | |
| From: Sally Haslanger (Persistence, Change and Explanation [1989], 8) | |
| A reaction: I think this is exactly right, and it is a powerful idea with wide implications for metaphysics. Haslanger claims that an understanding of 'substance' is needed, which leads towards my defence of essentialism. |
| 13927 | We must explain change amongst 'momentary entities', or else the world is inexplicable [Haslanger] |
| Full Idea: If the world of time-slices is to be explicable, then it must be possible to provide explanations of change understood as a continual generation and destruction of these 'momentary entities'. | |
| From: Sally Haslanger (Persistence, Change and Explanation [1989], 7) | |
| A reaction: While fans of time-slices can offer some sort of explanation, in the process of explaining a 'worm', there don't seem to be the sort of causal chains that we traditionally rely on. Maybe there are no explanations of anything? |
| 13928 | If the things which exist prior to now are totally distinct, they need not have existed [Haslanger] |
| Full Idea: How is the case in which A exists prior to B, but is distinct from B, different (especially from B's point of view) from the case in which nothing exists prior to B? | |
| From: Sally Haslanger (Persistence, Change and Explanation [1989], 7) | |
| A reaction: I sympathise with her view, but this isn't persuasive. For A substitute 'Sally's mother' and for B substitute 'Sally'. A 4D-ist could bite the bullet and say that, indeed, previous parts of my 'worm' need not have existed. |
| 13929 | Natural explanations give the causal interconnections [Haslanger] |
| Full Idea: Natural explanations work by showing the systematic causal interconnections between things. | |
| From: Sally Haslanger (Persistence, Change and Explanation [1989], 7) | |
| A reaction: On the whole I love this sort of idea, but I am wondering if this one prevents mathematical or logical explanations from being natural. |
| 13926 | Best explanations, especially natural ones, need grounding, notably by persistent objects [Haslanger] |
| Full Idea: I am not resting my ontology on a simple 'argument to the best explanation'. ..What I want to say is that there are general demands on a kind of explanation, in particular, natural explanation, which require that there are persisting things. | |
| From: Sally Haslanger (Persistence, Change and Explanation [1989], 5) | |
| A reaction: This is a really nice idea - that best explanation is not just about specific cases, but also about best foundations for explanations in general, which brings in our metaphysics. I defend the role of essences in these best explanations. |
| 10364 | Facts are about the world, not in it, so they can't cause anything [Bennett] |
| Full Idea: Facts are not the sort of item that can cause anything. A fact is a true proposition (they say); it is not something in the world but is rather something about the world. | |
| From: Jonathan Bennett (Events and Their Names [1988], p.22), quoted by Jonathan Schaffer - The Metaphysics of Causation 1.1 | |
| A reaction: Compare 10361. Good argument, but maybe 'fact' is ambiguous. See Idea 10365. Events are said to be more concrete, and so can do the job, but their individuation also seems to depend on a description (as Davidson has pointed out). |
| 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) |