  Nevertheless, even if this objection to Locke is thwarted, the others remain in force. For one thing, memory does seem to presuppose  personal identity, and so cannot constitute a criterion of it. For  another, identity is a transitive relation, while memory isn't, so  the latter can't be a criterion of the former. Finally, there is the  obvious worry that identity seems to persist through the loss of  memory: it's hard to believe that I would cease to exist were I to  undergo amnesia. It's for all these reasons that contemporary  theorists working in the Lockean tradition have had to make  significant changes to the theory to make it viable.