12017
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In all instances of identity, there must be some facts to ensure the identity [Forbes,G]
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Full Idea:
For each instance of identity or failure of identity, there must be facts in virtue of which that instance obtains. ..Enough has been said to lend this doctrine some plausibility.
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From:
Graeme Forbes (The Metaphysics of Modality [1985], 5.5)
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A reaction:
Penelope Mackie picks this out from Forbes as a key principle. It sounds to be in danger of circularity, unless the 'facts' can be cited without referring to, or implicitly making use of, identities - which seems unlikely.
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12024
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If we combined two clocks, it seems that two clocks may have become one clock. [Forbes,G]
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Full Idea:
If we imagine a possible world in which two clocks in a room make one clock from half the parts of each, the judgement 'these two actual clocks could have been a single clock' does not seem wholly false.
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From:
Graeme Forbes (The Metaphysics of Modality [1985], 7.4)
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A reaction:
You would, of course, have sufficient parts left over to make a second clock, so they look like a destroyed clock, so I don't think I find Forbes's intuition on this one very persuasive.
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11885
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Only individual essences will ground identities across worlds in other properties [Forbes,G, by Mackie,P]
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Full Idea:
Forbes argues that, unless we posit individual essences, we cannot guarantee that identities across possible worlds will be appropriately grounded in other properties.
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From:
report of Graeme Forbes (The Metaphysics of Modality [1985]) by Penelope Mackie - How Things Might Have Been 2.4
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A reaction:
There is a confrontation between Wiggins, who says identity is primitive, and Forbes, who says identity must be grounded in other properties. I think I side with Forbes.
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12015
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Non-trivial individual essence is properties other than de dicto, or universal, or relational [Forbes,G]
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Full Idea:
A non-trivial individual essence is properties other than a) those following from a de dicto truth, b) properties of existence and self-identity (or their cognates), c) properties derived from necessities in some other category.
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From:
Graeme Forbes (The Metaphysics of Modality [1985], 5.1)
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A reaction:
[I have compressed Forbes] Rather than adding all these qualificational clauses to our concept, we could just tighten up on the notion of a property, saying it is something which is causally efficacious, and hence explanatory.
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12013
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Essential properties depend on a category, and perhaps also on particular facts [Forbes,G]
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Full Idea:
The essential properties of a thing will typically depend upon what category of thing it is, and perhaps also on some more particular facts about the thing itself.
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From:
Graeme Forbes (The Metaphysics of Modality [1985], 5.1)
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A reaction:
I see no way of dispensing with the second requirement, in the cases of complex entities like animals. If all samples are the same, then of course we can define a sample's essence through its kind, but not if samples differ in any way.
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12020
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An individual might change their sex in a world, but couldn't have differed in sex at origin [Forbes,G]
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Full Idea:
In the time of a single world, the same individual can undergo a change of sex, but it is less clear that an individual of one sex could have been, from the outset, an individual of another.
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From:
Graeme Forbes (The Metaphysics of Modality [1985], 6.5)
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A reaction:
I don't find this support for essentiality of origin very persuasive. I struggle with these ideas. Given my sex yesterday, then presumably I couldn't have had a different sex yesterday. Given that pigs can fly, pigs can fly. What am I missing?
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11888
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Identities must hold because of other facts, which must be instrinsic [Forbes,G, by Mackie,P]
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Full Idea:
Forbes has two principles of identity, which we can call the No Bare Identities Principle (identities hold in virtue of other facts), and the No Extrinsic Determination Principle (that only intrinsic facts of a thing establish identity).
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From:
report of Graeme Forbes (The Metaphysics of Modality [1985], 127-8) by Penelope Mackie - How Things Might Have Been 2.7
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A reaction:
The job of the philosopher is to prise apart the real identities of things from the way in which we conceive of identities. I take these principles to apply to real identities, not conceptual identities.
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