What if the brain in vitro (in the above example) could not communicate with us at all? Would we still think it is possessed of a self? The biological functions of people in coma are maintained. But do they have an identity, a self? If yes, why do we "pull the plug" on them so often? It would seem (as it did to Locke) that we accept that someone has a self-identity if: (a) He has the same hardware as we do (notably, a brain) and (b) He communicates his humanly recognizable and comprehensible inner world to us and manipulates his environment. We accept that he has a given (i.e., the same continuous) self-identity if (c) He shows consistent intentional (i.e., willed) patterns ("memory") in doing (b) for a long period of time. It seems that we accept that we have a self-identity (i.e., we are self-conscious) if (a) We discern (usually through introspection) long term consistent intentional (i.e., willed) patterns ("memory") in our manipulation ("relating to") of our environment and (b) Others accept that we have a self-identity (Herbert Mead, Feuerbach). Dan (probably) has the same hardware as we do (a brain). He communicates his (humanly recognizable and comprehensible) inner world to us (which is how he manipulates us and his environment). Thus, Dan clearly has a self-identity. But he is inconsistent. His intentional (willed) patterns, his memory, are incompatible with those demonstrated by Dan before the accident. Though he clearly is possessed of a self-identity, we cannot say that he has the SAME self-identity he possessed before the crash. In other words, we cannot say that he, indeed, is Dan. Dan himself does not feel that he has a self-identity at all. He discerns intentional (willed) patterns in his manipulation of his environment but, due to his amnesia, he cannot tell if these are consistent, or long term. In other words, Dan has no memory. Moreover, others do not accept him as Dan (or have their doubts) because they have no memory of Dan as he is now. Interim conclusion: Having a memory is a necessary and sufficient condition for possessing a self-identity. III. Repression Yet, resorting to memory to define identity may appear to be a circular (even tautological) argument. When we postulate memory - don't we already presuppose the existence of a "remembering agent" with an established self-identity?