Full Idea
If memory were the sole criterion of personal identity it would have to be the sole criterion that we use in making identity statements about persons other than ourselves.
Gist of Idea
If memory is the sole criterion of identity, we ought to use it for other people too
Source
Sydney Shoemaker (Personal Identity and Memory [1959], §4)
Book Reference
'Personal Identity', ed/tr. Perry,John [University of California 1975], p.127
A Reaction
From Locke's point of view, he is much less certain about the continued identity of other people, because he allows the possibility of transference of minds. Even we might reject physical identity, if a person had suffered a severe trauma.