Sunk costs, rationality, and acting for the sake of the past

If you are more likely to continue a course of action in virtue of having previously invested in that course of action, then you tend to honor sunk costs. It is widely thought both that (i) individuals often do give some weight to sunk costs in their decision-making and that (ii) it is irrational for them to do so. In this paper I attempt to cast doubt on the conventional wisdom about sunk costs, understood as the conjunction of these two claims.