16960
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If possibilitiy is relative, that might make accessibility non-transitive, and T the correct system [Dummett]
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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.
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From:
Michael Dummett (Could There Be Unicorns? [1983], 8)
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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.
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16958
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In S4 the actual world has a special place [Dummett]
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Full Idea:
In S4 logic the actual world is, in itself, special, not just from our point of view.
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From:
Michael Dummett (Could There Be Unicorns? [1983], 8)
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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?
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6019
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If someone squashed a horse to make a dog, something new would now exist [Mnesarchus]
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Full Idea:
If, for the sake of argument, someone were to mould a horse, squash it, then make a dog, it would be reasonable for us on seeing this to say that this previously did not exist but now does exist.
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From:
Mnesarchus (fragments/reports [c.120 BCE]), quoted by John Stobaeus - Anthology 179.11
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A reaction:
Locke would say it is new, because the substance is the same, but a new life now exists. A sword could cease to exist and become a new ploughshare, I would think. Apply this to the Ship of Theseus. Is form more important than substance?
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16959
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If possible worlds have no structure (S5) they are equal, and it is hard to deny them reality [Dummett]
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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.
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From:
Michael Dummett (Could There Be Unicorns? [1983], 8)
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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….
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22481
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There is no restitution after a dilemma, if it only involved the agent, or just needed an explanation [Foot, by PG]
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Full Idea:
The 'remainder' after a dilemma can't be a matter of apology and restitution, because the dilemma may only involve the agent's own life, and in the case of broken promises we only owe an explanation, if the breaking is justifiable.
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From:
report of Philippa Foot (Moral Dilemmas Revisited [1995], p.183) by PG - Db (ideas)
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A reaction:
But what if someone has been financially ruined by it? If the agent feels guilty about that, is getting over it the rational thing to do? (Foot says that is an new obligation, and not part of the original dilemma).
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16954
|
Generalised talk of 'natural kinds' is unfortunate, as they vary too much [Dummett]
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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.
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From:
Michael Dummett (Could There Be Unicorns? [1983], 2)
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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.
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