[Thrombus in the left atrium -- is it always treated properly?].

According to Mark Johnston's Personite Problem, Perdurantism-the view that persons are maximal fusions of person-stages-should be rejected, as it fails to account for the moral status of non-maximal fusions that overlap a person (personites). His Duplication Argument claims that personites have persons as duplicates in other metaphysically possible worlds. Since duplicates share all intrinsic descriptive properties, they must share normative ones, including moral status. I challenge this by accepting Johnston's duplication claim but rejecting its moral conclusion. Perdurantists can respond by adopting Moral Contingentism: the view that pure moral laws are not metaphysically necessary but only normatively necessary, hence metaphysically contingent. These perdurantists can maintain metaphysically possible worlds where personites have person-duplicates, while holding these worlds normatively impossible (i.e., countermoral). Countermoral worlds-differing in their pure moral laws and thus how they ground moral status-cannot confer moral status on personites through duplication in normatively possible worlds, including the actual one.