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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15312
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We get the idea of power by abstracting from ropes, magnets and electric shocks [Priestley]
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Full Idea:
A rope sustains weight, a magnet attracts iron, a charged electrical jar gives a shock, and from these and other similar observations, we get the idea of power, universally and abstractly considered.
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From:
Joseph Priestley (Theological and other works [1790], p.191), quoted by Harré,R./Madden,E.H. - Causal Powers 9.II.B
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A reaction:
I agree with this, in that we appear to be observing powers directly, and are not observing something which can then be reduced to non-powers. Nature just can't be a set of inert structures, with forces 'imposed' on them.
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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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16954
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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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15311
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Attraction or repulsion are not imparted to matter, but actually constitute it [Priestley]
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Full Idea:
Attraction or repulsion appear to me not to be properly what is imparted to matter, but what really makes it what it is, in so much that, without it, it would be nothing at all.
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From:
Joseph Priestley (Theological and other works [1790], p.237), quoted by Harré,R./Madden,E.H. - Causal Powers 9.II.B
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A reaction:
This is music to the ears of anyone who thinks that powers are the fundamentals of nature (like me).
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