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Ideas of Allan Gibbard, by Text

[American, b.1942, At the University of Michigan.]

1975 Contingent Identity
Intro p.187 If a statue is identical with the clay of which it is made, that identity is contingent
     Full Idea: Under certain conditions a clay statue is identical with the piece of clay of which it is made, and if this is so then the identity is contingent.
     From: Allan Gibbard (Contingent Identity [1975], Intro)
     A reaction: This initiated the modern debate about statues, and it is an attack on Kripke's claim that if two things are identical, then they are necessarily identical. Kripke seems right about Hesperus and Phosphorus, but not about the statue.
I p.188 Two identical things must share properties - including creation and destruction times
     Full Idea: For two things to be strictly identical, they must have all properties in common. That means, among other things, that they must start to exist at the same time and cease to exist at the same time.
     From: Allan Gibbard (Contingent Identity [1975], I)
     A reaction: I don't accept that coming into existence at time t is a 'property' of a thing. Coincident objects give you the notion of 'existing as' something, which complicates the whole story.
I p.189 A 'piece' of clay begins when its parts stick together, separately from other clay
     Full Idea: A 'piece' of clay is a portion of clay which comes into existence when all of its parts come to be stuck to each other, and cease to be stuck to any clay which is not a part of the portion.
     From: Allan Gibbard (Contingent Identity [1975], I)
     A reaction: The sort of gormlessly elementary things that philosophers find themselves having to say, but this is a good basic assertion for a discussion of statue and clay, and I can't think of an objection to it.
I p.190 Clay and statue are two objects, which can be named and reasoned about
     Full Idea: The piece of clay and the statue are 'objects' - that is to say, they can be designated with proper names, and the logic we ordinarily use will still apply.
     From: Allan Gibbard (Contingent Identity [1975], I)
     A reaction: An interesting indication of the way that 'object' is used in modern analytic philosophy, which may not be the way that it is used in ordinary English. The number 'seven', for example, seems to be an object by this criterion.
III p.194 We can only investigate the identity once we have designated it as 'statue' or as 'clay'
     Full Idea: To ask meaningfully what that thing would be, we must designate it either as a statue or as a piece of clay. What that thing would be, apart from the way it is designated, is a question without meaning.
     From: Allan Gibbard (Contingent Identity [1975], III)
     A reaction: He obviously has a powerful point, but to suggest that we can only investigate a mysterious object once we have designated it as something sounds daft. It would ruin the fun of archaeology.
III p.195 A particular statue has sortal persistence conditions, so its origin defines it
     Full Idea: A proper name like 'Goliath' denotes a thing in the actual world, and invokes a sortal with certain persistence criteria. Hence its origin makes a statue the statue that it is, and if statues in different worlds have the same beginning, they are the same.
     From: Allan Gibbard (Contingent Identity [1975], III)
     A reaction: Too neat. There are vague, ambiguous and duplicated origins. Persistence criteria can shift during the existence of a thing (like a club which changes its own constitution). In replicated statues, what is the status of the mould?
III p.198 Naming a thing in the actual world also invokes some persistence criteria
     Full Idea: The reference of a name in the actual world is fixed partly by invoking a set of persistence criteria which determine what thing it names.
     From: Allan Gibbard (Contingent Identity [1975], III)
     A reaction: This is offered as a modification to Kripke, to deal with the statue and clay. I fear that the 'persistence criteria' may be too vague, and too subject to possible change after the origin, to do the job required.
IV p.198 Possible worlds identity needs a sortal
     Full Idea: Identity across possible worlds makes sense only with respect to a sortal
     From: Allan Gibbard (Contingent Identity [1975], IV)
     A reaction: See Gibbard's other ideas from this paper. I fear that the sortal invoked is too uncertain and slippery to do any useful job, and I can't see any principled difficulty with naming something before you can think of a sortal for it.
V p.200 Claims on contingent identity seem to violate Leibniz's Law
     Full Idea: The most prominent objection to contingent identity (as in the case of the statue and its clay) is that it violates Leibniz's Law.
     From: Allan Gibbard (Contingent Identity [1975], V)
     A reaction: Depends what you mean by a property. The trickiest one would be that the statue has (right now) a disposition to be worth a lot, but the clay doesn't. But I don't think that is really a property of the statue. Properties are a muddle.
V p.201 Leibniz's Law isn't just about substitutivity, because it must involve properties and relations
     Full Idea: As a general law of substitutivity of identicals, Leibniz's Law is false. It is a law about properties and relations, that if two things are identical, they have the same properties and relations. It only works in contexts which attribute those.
     From: Allan Gibbard (Contingent Identity [1975], V)
     A reaction: I'm not convinced about relations, which are not intrinsic properties. Under different descriptions, the relations to human minds might differ.
VII p.207 Essentialism is the existence of a definite answer as to whether an entity fulfils a condition
     Full Idea: Essentialism for a class of entities is that for one entity and a condition which it fulfills, the question of whether it necessarily fulfills the condition has a definite answer apart from the way the entity is specified.
     From: Allan Gibbard (Contingent Identity [1975], VII)
     A reaction: Yet another definition of essentialism, but resting, as usual in modern discussions, entirely on the notion of necessity. Kit Fine's challenge is that if you investigate the source of the necessity, it turns out to be an essence.
VII p.207 Essentialism for concreta is false, since they can come apart under two concepts
     Full Idea: Essentialism for the class of concrete things is false, since a statue necessarily fulfils a condition as 'Goliath', but only contingently fulfils it as 'lumpl'. On the other hand, essentialism for the class of individual concepts can be true.
     From: Allan Gibbard (Contingent Identity [1975], VII)
     A reaction: This rests on his definition of essentialism in Idea 14076. He rests his essentialism about concepts on an account given by Carnap ('Meaning and Necessity' 41). The essence of a statue and the essence of a lump of clay do seem distinct.
VII p.208 Only concepts, not individuals, can be the same across possible worlds
     Full Idea: It is meaningless to talk of the same concrete thing in different possible worlds, ...but it makes sense to speak of the same individual concept, which is just a function which assigns to each possible world in a set an individual in that world.
     From: Allan Gibbard (Contingent Identity [1975], VII)
     A reaction: A lovely bold response to the problem of transworld identity, but one which needs investigation. It sounds very promising to me. 'Aristotle' is a cocept, not a name. There is no separate category of 'names'. Wow. (Attach dispositions to concepts?).
X p.212 Kripke's semantics needs lots of intuitions about which properties are essential
     Full Idea: To use Kripke's semantics, one needs extensive intuitions that certain properties are essential and others accidental.
     From: Allan Gibbard (Contingent Identity [1975], X)
     A reaction: As usual, we could substitute the word 'necessary' for 'essential' without changing his meaning. If we are always referring to 'our' Hubert Humphrey is speculations about him, then nearly all of his properties will be necessary ones.