  Some might see the loss of personhood as a particularly clear-cut sign of a change in numerical identity: if the current self is not even a person, surely the current self cannot be the same person as the earlier self. However, as David DeGrazia has emphasized, this line of reasoning rests on an undefended (and controversial) assumption that we are essentially persons (DeGrazia 1999). For if we are not essentially persons — but, rather, for example, conscious minds of some other, less complex kind — an individual may very well lose the properties of a person without any threat to his numerical survival.