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Single Idea 9848

[filed under theme 9. Objects / F. Identity among Objects / 2. Defining Identity ]

Full Idea

Husserl says the only ground for assuming the replaceability of one content by another is their identity; we are therefore not entitled to define their identity as consisting in their replaceability.

Gist of Idea

Content is replaceable if identical, so replaceability can't define identity

Source

report of Michael Dummett (Frege philosophy of mathematics [1991]) by Michael Dummett - Frege philosophy of mathematics Ch.12

Book Ref

Dummett,Michael: 'Frege: philosophy of mathematics' [Duckworth 1991], p.142

A Reaction

This is a direct challenge to Frege. Tricky to arbitrate, as it is an issue of conceptual priority. My intuition is with Husserl, but maybe the two are just benignly inerdefinable.

The 14 ideas with the same theme [whether identity can be defined - and how]:

22322 You can't define identity by same predicates, because two objects with same predicates is assertable [Wittgenstein]
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, by 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]
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]
16020 Identity can only be characterised in a second-order language [Noonan]
6053 Identity is as basic as any concept could ever be [McGinn]