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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.
Gist of Idea
Leibniz's Law isn't just about substitutivity, because it must involve properties and relations
Source
Allan Gibbard (Contingent Identity [1975], V)
Book Ref
-: 'Journal of Symbolic Logic' [-], p.201
A Reaction
I'm not convinced about relations, which are not intrinsic properties. Under different descriptions, the relations to human minds might differ.
Related Idea
Idea 8650 Things are the same if one can be substituted for the other without loss of truth [Leibniz]
| 14064 | If a statue is identical with the clay of which it is made, that identity is contingent [Gibbard] |
| 14066 | A 'piece' of clay begins when its parts stick together, separately from other clay [Gibbard] |
| 14067 | Clay and statue are two objects, which can be named and reasoned about [Gibbard] |
| 14065 | Two identical things must share properties - including creation and destruction times [Gibbard] |
| 14070 | A particular statue has sortal persistence conditions, so its origin defines it [Gibbard] |
| 14069 | We can only investigate the identity once we have designated it as 'statue' or as 'clay' [Gibbard] |
| 14071 | Naming a thing in the actual world also invokes some persistence criteria [Gibbard] |
| 14072 | Possible worlds identity needs a sortal [Gibbard] |
| 14073 | Claims on contingent identity seem to violate Leibniz's Law [Gibbard] |
| 14074 | Leibniz's Law isn't just about substitutivity, because it must involve properties and relations [Gibbard] |
| 14076 | Essentialism is the existence of a definite answer as to whether an entity fulfils a condition [Gibbard] |
| 14077 | Essentialism for concreta is false, since they can come apart under two concepts [Gibbard] |
| 14078 | Only concepts, not individuals, can be the same across possible worlds [Gibbard] |
| 14079 | Kripke's semantics needs lots of intuitions about which properties are essential [Gibbard] |