Locke on personal identity
CFS Lecture by Galen Strawson, Professor at the Department of Philosophy, University of Texas at Austin and Affiliated Professor in Philosophy at the Department of Media, Cognition and Communications, University of Copenhagen.
Many think John Locke’s account of personal identity is inconsistent and circular. It’s neither of these things. The root causes of the misreading are  the mistake of thinking that Locke uses ‘consciousness’ to mean memory,  failure to appreciate the importance of the ‘concernment’ that always accompanies ‘consciousness’ on Locke’s view,  the tendency to take the term person, in Locke’s text, as if it were (only) some kind of fundamental sortal term like ‘chair’ or ‘human being’, and to fail to take proper account of Locke’s use of it as a ‘forensic’ term (§26).
Locke is not interested in the standard question of personal identity, i.e. ‘what has to be the case for it to be true that person P1 at (time) t1 is the same as person P2 at (time) t2, the same persisting subject of experience?’
He is interested in four other questions, all of which he answers. They are [A] What does a subject of experience that qualifies as a person actually consist of, ontologically speaking, considered at any given time? [B] What mental capacities must a subject of experience have in order to qualify as a person? [C] What sorts of changes of substantial composition can a subject of experience that qualifies as a person undergo while continuing to exist? [D] Which actions is a subject of experience who qualifies as a person responsible for? I say what his answers are.