Prudence, Sunk Costs, and the Temporally Extended Self

Many find it reasonable to take our past actions into account when making choices for the future. In this paper, I address two important issues regarding taking past investments into account in prudential deliberation. The first is the charge that doing so commits the fallacy of honoring sunk costs. I argue that while it is indeed irrational to care about sunk costs, past investments are not sunk costs when we can change their teleological significance, roughly their contribution to our excellence as temporally extended, reasons-responsive, and goal-directed agents. I suggest some general principles for evaluating such significance. Second, it’s a live issue whether we should care about the fate of our past projects, even if we can now affect it. I reject Dale Dorsey’s recent answer, and argue that the puzzle he addresses turns out to be merely apparent, if we take seriously the fact that we are temporally extended.