Ideas of Allan Gibbard, by Theme

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

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9. Objects / B. Unity of Objects / 3. Unity Problems / c. Statue and clay
If a statue is identical with the clay of which it is made, that identity is contingent
A 'piece' of clay begins when its parts stick together, separately from other clay
Clay and statue are two objects, which can be named and reasoned about
We can only investigate the identity once we have designated it as 'statue' or as 'clay'
9. Objects / D. Essence of Objects / 7. Essence and Necessity / a. Essence as necessary properties
Essentialism is the existence of a definite answer as to whether an entity fulfils a condition
9. Objects / D. Essence of Objects / 15. Against Essentialism
Essentialism for concreta is false, since they can come apart under two concepts
9. Objects / E. Objects over Time / 12. Origin as Essential
A particular statue has sortal persistence conditions, so its origin defines it
9. Objects / F. Identity among Objects / 6. Identity between Objects
Claims on contingent identity seem to violate Leibniz's Law
9. Objects / F. Identity among Objects / 8. Leibniz's Law
Two identical things must share properties - including creation and destruction times
Leibniz's Law isn't just about substitutivity, because it must involve properties and relations
10. Modality / E. Possible worlds / 3. Transworld Objects / a. Transworld identity
Only concepts, not individuals, can be the same across possible worlds
Possible worlds identity needs a sortal
10. Modality / E. Possible worlds / 3. Transworld Objects / b. Rigid designation
Kripke's semantics needs lots of intuitions about which properties are essential
19. Language / D. Theories of Reference / 3. Direct Reference / b. Causal reference
Naming a thing in the actual world also invokes some persistence criteria