Full Idea
For any two sense-experiences to belong to the sense-history of the same self it is necessary and sufficient that they should contain organic sense-contents which are elements of the same body.
Gist of Idea
Two experiences belong to one self if their contents belong with one body
Source
A.J. Ayer (Language,Truth and Logic [1936], Ch.7)
Book Reference
Ayer,A.J.: 'Language, Truth and Logic' [Penguin 1974], p.165
A Reaction
This makes more sense if you are a realist about organic bodies, but less sense if (like Ayer) you define the body in terms of sense-experiences. It is a stab at what is now called 'animalism', but needs an account of brain transplant thought-experiments.