Full Idea
Identity is utterly simple and unproblematic. Everything is identical to itself; nothing is ever identical to anything except itself. There is never any problem about what makes something identical to itself; nothing can ever fail to be.
Gist of Idea
Identity is simple - absolutely everything is self-identical, and nothing is identical to another thing
Source
David Lewis (On the Plurality of Worlds [1986], 4.1)
Book Reference
Lewis,David: 'On the Plurality of Worlds' [Blackwell 2001], p.192
A Reaction
I have great problems with expressing this concept as a thing being 'identical to itself'. I will always say that it 'has an identity'. But then it is problematical, because what constitutes an identity? When do dispersing clouds lose it?
Related Ideas
Idea 15969 Two things can never be identical, so there is no problem [Lewis]
Idea 16143 It is absurd that a this and a substance should be composed of a quality [Aristotle]
Idea 19394 Inequality can be brought infinitely close to equality [Leibniz]