17594 | We can paraphrase 'x=y' as a sequence of the form 'if Fx then Fy' [Quine] |
10797 | Substitutivity won't fix identity, because expressions may be substitutable, but not refer at all [Marcus (Barcan)] |
9848 | Content is replaceable if identical, so replaceability can't define identity [Dummett on Dummett] |
9842 | Frege introduced criteria for identity, but thought defining identity was circular [Dummett] |
11831 | The formal properties of identity are reflexivity and Leibniz's Law [Wiggins] |
16497 | Leibniz's Law (not transitivity, symmetry, reflexivity) marks what is peculiar to identity [Wiggins] |
16498 | Identity cannot be defined, because definitions are identities [Wiggins] |
16502 | Identity is primitive [Wiggins] |
16015 | Problems about identity can't even be formulated without the concept of identity [Noonan] |
16020 | Identity can only be characterised in a second-order language [Noonan] |
16017 | Identity is usually defined as the equivalence relation satisfying Leibniz's Law [Noonan] |
16016 | Identity definitions (such as self-identity, or the smallest equivalence relation) are usually circular [Noonan] |
6053 | Identity is as basic as any concept could ever be [McGinn] |