An animalist will insist people are each an animal, and that “person” either picks out that animal or is a phase sortal applying to one stage of the animal's life. First-person perspectives are sometimes claimed to present a unique form of “placement problem”. The reidentification question asks about the identity conditions of a person at two times. The characterisation question, less obviously, asks about what unifies characteristics over time; the sort of practical orientation towards the concept of personhood it embodies makes no real sense without persons persisting over time. If liberal naturalism can solve these temporal placement problems, it will be able to do so in virtue of the fact that “now” can always be coordinated to a point in time on a four-dimensionalist/eternalist/block universe view of time. Placement problems so construed presuppose a more-or-less stable “thing” that needs to be placed.