Grayling, A. C. "Brain Science and the Search for the Self." NEW SCIENTIST March 20, 2009.

Belief in the idea of a substantial soul - a "you" that is separate from your body - was waning. In the absence of this metaphysical entity as a convenience for underpinning personal identity, what, asked Molyneaux, makes the retired general continuous with the eager subaltern of 40 years before, and he with the red-cheeked baby in his nurse's arms 20 years before that? In response, Locke added a chapter to his second edition which instantly caused a storm of controversy and has been famous ever since in the annals of philosophy. In that chapter Locke argued that a person's identity over time resides in their consciousness (he coined this term, and here introduced it to the English language) of being the same self at a later time as at an earlier, and that the mechanism that makes this possible is memory. Whereas a stone is the same stone over time because it is the very same lump of matter - or almost, allowing for erosion - and an oak tree is identical with its originating acorn because it is the same continuous organisation of matter, a person is only the same through time if he or she is self-aware of being so. Memory loss interrupts identity, and complete loss of memory is therefore loss of the self. . . . Read the rest here: http://www.newscientist.com/article/mg20127006.800-will-brain-science-reveal-a-self.html.