Full Idea
Whatever changes a person endures, his several parts are still connected by the relation of causation.
Gist of Idea
The parts of a person are always linked together by causation
Source
David Hume (Treatise of Human Nature [1739], I.IV.6)
Book Reference
'Personal Identity', ed/tr. Perry,John [University of California 1975], p.170
A Reaction
However, the opposite ends of the universe are linked together by causation, so that will not suffice for a theory of personal identity. One might try to specify a complex and tight network of causation (like a brain!) instead of just 'connection'.