Full Idea
I believe Hume offers an interesting if sketchy theory of personal identity, a causal theory, disguised as the revolutionary discovery that there is no such thing as personal identity
Gist of Idea
Hume gives us an interesting sketchy causal theory of personal identity
Source
comment on David Hume (Treatise of Human Nature [1739], I.IV.6) by John Perry - Introduction to 'Personal Identity' Intro
Book Reference
'Personal Identity', ed/tr. Perry,John [University of California 1975], p.170
A Reaction
There is certainly a theory there, even though Hume ceased to believe in it, which is nowadays covered by the idea that personal identity is a 'fiction', an arbitrary idea that reifies the focus and direction of a bundle of mental events.