Combining Texts

All the ideas for 'Commentary on 'De Anima'', 'On Multiplying Entities' and 'Could There Be Unicorns?'

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14 ideas

2. Reason / B. Laws of Thought / 6. Ockham's Razor
8207 The quest for simplicity drove scientists to posit new entities, such as molecules in gases [Quine]
     Full Idea: It is the quest for system and simplicity that has kept driving the scientist to posit further entities as values of his variables. By positing molecules, Boyles' law of gases could be assimilated into a general theory of bodies in motion.
     From: Willard Quine (On Multiplying Entities [1974], p.262)
     A reaction: Interesting that a desire for simplicity might lead to multiplications of entities. In fact, I presume molecules had been proposed elsewhere in science, and were adopted in gas-theory because they were thought to exist, not because simplicity is nice.
8208 In arithmetic, ratios, negatives, irrationals and imaginaries were created in order to generalise [Quine]
     Full Idea: In classical arithmetic, ratios were posited to make division generally applicable, negative numbers to make subtraction generally applicable, and irrationals and finally imaginaries to make exponentiation generally applicable.
     From: Willard Quine (On Multiplying Entities [1974], p.263)
     A reaction: This is part of Quine's proposal (c.f. Idea 8207) that entities have to be multiplied in order to produce simplicity. He is speculating. Maybe they are proposed because they are just obvious, and the generality is a nice side-effect.
4. Formal Logic / D. Modal Logic ML / 1. Modal Logic
16951 It was realised that possible worlds covered all modal logics, if they had a structure [Dummett]
     Full Idea: The new discovery was that with a suitable structure imposed on the space of possible worlds, the Leibnizian idea would work for all modal logics.
     From: Michael Dummett (Could There Be Unicorns? [1983], 1)
4. Formal Logic / D. Modal Logic ML / 3. Modal Logic Systems / a. Systems of modal logic
16952 If something is only possible relative to another possibility, the possibility relation is not transitive [Dummett]
     Full Idea: If T is only possible if S obtains, and S is possible but doesn't obtain, then T is only possible in the world where S obtains, but T is not possible in the actual world. It follows that the relation of relative possibility is not transitive.
     From: Michael Dummett (Could There Be Unicorns? [1983], 1)
     A reaction: [compressed]
16953 Relative possibility one way may be impossible coming back, so it isn't symmetrical [Dummett]
     Full Idea: If T is only possible if S obtains, T and S hold in the actual world, and S does not obtain in world v possible relative to the actual world, then the actual is not possible relative to v, since T holds in the actual. Accessibility can't be symmetrical.
     From: Michael Dummett (Could There Be Unicorns? [1983], 1)
4. Formal Logic / D. Modal Logic ML / 3. Modal Logic Systems / d. System T
16960 If possibilitiy is relative, that might make accessibility non-transitive, and T the correct system [Dummett]
     Full Idea: If some world is 'a way the world might be considered to be if things were different in a certain respect', that might show that the accessibility relation should not be taken to be transitive, and we should have to adopt modal logic T.
     From: Michael Dummett (Could There Be Unicorns? [1983], 8)
     A reaction: He has already rejected symmetry from the relation, for reasons concerning relative identity. He is torn between T and S4, but rejects S5, and opts not to discuss it.
4. Formal Logic / D. Modal Logic ML / 3. Modal Logic Systems / g. System S4
16958 In S4 the actual world has a special place [Dummett]
     Full Idea: In S4 logic the actual world is, in itself, special, not just from our point of view.
     From: Michael Dummett (Could There Be Unicorns? [1983], 8)
     A reaction: S4 lacks symmetricality, so 'you can get there, but you can't get back', which makes the starting point special. So if you think the actual world has a special place in modal metaphysics, you must reject S5?
7. Existence / B. Change in Existence / 4. Events / c. Reduction of events
8205 Explaining events just by bodies can't explain two events identical in space-time [Quine]
     Full Idea: An account of events just in terms of physical bodies does not distinguish between events that happen to take up just the same portion of space-time. A man's whistling and walking would be identified with the same temporal segment of the man.
     From: Willard Quine (On Multiplying Entities [1974], p.260)
     A reaction: We wouldn't want to make his 'walking' and his 'strolling' two events. Whistling and walking are different because different objects are involved (lips and legs). Hence a man is not (ontologically) a single object.
10. Modality / A. Necessity / 11. Denial of Necessity
8206 Necessity could be just generalisation over classes, or (maybe) quantifying over possibilia [Quine]
     Full Idea: The need to add a note of necessity to 'all black crows are black' could be met by a generalisation over classes (what belongs to sets x and y belongs to y), or maybe be quantifying over possible particulars.
     From: Willard Quine (On Multiplying Entities [1974], p.262)
     A reaction: He dislikes the second strategy because 'unactualized particulars are an obscure and troublesome lot'. The second is the strategy of Lewis. I think necessity starts to creep back in as soon as you ask WHY a generalisation holds true.
10. Modality / E. Possible worlds / 1. Possible Worlds / a. Possible worlds
16957 Possible worlds aren't how the world might be, but how a world might be, given some possibility [Dummett]
     Full Idea: The equation of a possible world with the way that the (actual) world might be is wrong: the way a distant world might be is not a way the world might be, but a way we might allow it to be given how some intervening world might be.
     From: Michael Dummett (Could There Be Unicorns? [1983], 8)
     A reaction: The point here is that a system of possible worlds must include relative possibilities as well as actual possibilities. Dummett argues against S5 modal logic, which makes them all equal. Things impossible here might become possible. Nice.
10. Modality / E. Possible worlds / 1. Possible Worlds / c. Possible worlds realism
16959 If possible worlds have no structure (S5) they are equal, and it is hard to deny them reality [Dummett]
     Full Idea: If our space of possible worlds has no structure, as in the semantics for S5, then, from the standpoint of the semantics, all possible worlds are on the same footing; it then becomes difficult to resist the claim that all are equally real.
     From: Michael Dummett (Could There Be Unicorns? [1983], 8)
     A reaction: This is a rather startling and interesting claim, given that modern philosophy seems full of thinkers who both espouse S5 for metaphysics, and also deny Lewisian realism about possible worlds. I'll ponder that one. Must read the new Williamson….
22. Metaethics / B. Value / 2. Values / e. Death
16764 The soul conserves the body, as we see by its dissolution when the soul leaves [Toletus]
     Full Idea: Every accident of a living thing, as well as all its organs and temperaments and its dispositions are conserved by the soul. We see this from experience, since when that soul recedes, all these dissolve and become corrupted.
     From: Franciscus Toletus (Commentary on 'De Anima' [1572], II.1.1), quoted by Robert Pasnau - Metaphysical Themes 1274-1671 24.5
     A reaction: A nice example of observing a phenemonon, but not being able to observe the dependence relation the right way round. Compare Descartes in Idea 16763.
23. Ethics / C. Virtue Theory / 1. Virtue Theory / d. Virtue theory critique
16956 To explain generosity in a person, you must understand a generous action [Dummett]
     Full Idea: It cannot be explained what it is for a person to be generous without first explaining what it is for an action to be generous.
     From: Michael Dummett (Could There Be Unicorns? [1983], 4)
     A reaction: I presume a slot machine can't be 'generous', even if it favours the punter, so you can't specify a generous action without making reference to the person. A benign circle, as Aristotle says.
26. Natural Theory / B. Natural Kinds / 7. Critique of Kinds
16954 Generalised talk of 'natural kinds' is unfortunate, as they vary too much [Dummett]
     Full Idea: In my view, Kripke's promotion of 'natural kinds', coverning chemical substances and animal and plant species, is unfortunate, since these are rather different types of things, and words used for them behave differently.
     From: Michael Dummett (Could There Be Unicorns? [1983], 2)
     A reaction: My view is that the only significant difference among natural kinds is their degree of stability in character. Presumably particles, elements and particular molecules are fairly invariant, but living things evolve.