According to biological continuity views of personal identity,
existing at one time is a
another time if and only if the first mentioned person’s biological organism
is continuous with the second thing’s biological organism.
Reading (optional): Olson, E. T. (1997). The human animal: Personal identity without psychology. Oxford Uni- versity Press, Oxford.
If ‘the relations of practical concerns that typically go along with our identity through time are closely connected with psychological continuity
[...], then the Biological Approach does have an interesting ethical consequence,
namely that those practical relations are not necessarily connected with numerical identity’
(Olson, 1997 p. 70).
Reading (optional): Olson, E. T. (1997). The human animal: Personal identity without psychology. Oxford University Press, Oxford.
Psychological Continuity and Fission
If you could be psychologically continuous with two distinct future individuals
(that is, if fission is possible), then
psychological continuity views of personal identity cannot be correct.
Reading (optional): Shoemaker, D. (2019). Personal Identity and Ethics. In Zalta, E. N., editor, The Stanford Encyclopedia of Philosophy. Metaphysics Research Lab, Stanford University, winter 2019 edition.
Lewis was right, ‘Identity is utterly simple and unproblematic’.
Or so I claim. But maybe you can show this is wrong.
Reading (optional): (hard) Sider, T. (2001). Criteria of Personal Identity and the Limits of Conceptual Analysis. Nouˆs, 35(s15):189–209