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Single Idea 4942

[filed under theme 9. Objects / F. Identity among Objects / 8. Leibniz's Law ]

Full Idea

It seems to me that the Leibnizian principle of the indiscernibility of identicals (not to be confused with the identity of indiscernibles) is as self-evident as the law of contradiction.

Gist of Idea

The indiscernibility of identicals is as self-evident as the law of contradiction

Source

Saul A. Kripke (Naming and Necessity preface [1980], p.03)

Book Ref

Kripke,Saul: 'Naming and Necessity' [Blackwell 1980], p.3

A Reaction

This seems obviously correct, as it says no more than that a thing has whatever properties it has. If a difference is discerned, either you have made a mistake, or it isn't identical.

The 18 ideas with the same theme [identical objects must have identical features or truths]:

11840 Only if two things are identical do they have the same attributes [Aristotle]
16768 Two things are different if something is true of one and not of the other [Duns Scotus]
17255 Two bodies differ when (at some time) you can say something of one you can't say of the other [Hobbes]
17173 Two substances can't be the same if they have different attributes [Spinoza]
16073 Leibniz's Law is incomplete, since it includes a non-relativized identity predicate [Geach, by Wasserman]
4942 The indiscernibility of identicals is as self-evident as the law of contradiction [Kripke]
11839 Do both 'same f as' and '=' support Leibniz's Law? [Wiggins]
11845 Substitutivity, and hence most reasoning, needs Leibniz's Law [Wiggins]
14065 Two identical things must share properties - including creation and destruction times [Gibbard]
14074 Leibniz's Law isn't just about substitutivity, because it must involve properties and relations [Gibbard]
16019 Leibniz's Law must be kept separate from the substitutivity principle [Noonan]
16018 Indiscernibility is basic to our understanding of identity and distinctness [Noonan]
6050 Leibniz's Law presupposes the notion of property identity [McGinn]
6049 Leibniz's Law says 'x = y iff for all P, Px iff Py' [McGinn]
6048 Leibniz's Law is so fundamental that it almost defines the concept of identity [McGinn]
12236 Leibniz's Law is an essentialist truth [Oderberg]
14754 If you say Leibniz's Law doesn't apply to 'timebound' properties, you are no longer discussing identity [Sider]
16225 If two things might be identical, there can't be something true of one and false of the other [Hawley]