Abstract: Discusses numerical identity, or being one and the same, qualitative identity, or being exactly similar, personal identity, or what is involved in our continued existence over time. According to the Physical Criterion, our identity over time consists in the continued existence of enough of our brain. According to the Psychological Criterion, our identity consists in overlapping chains of psychological continuity and connectedness. The chapter discusses how we are inclined to believe that, even in purely imagined cases, our identity must be determinate. When we ask – Would I still exist? Would that future person be me?, it seems that it must always have an answer.

Keywords: body, brain, connectedness, continuity, identity, numerical identity, person, personal identity, physical criterion, psychological criterion, qualitative identity, reductionism,