Internalities and Paternalism: Applying the Compensation Criterion to Multiple Selves across Time

One reason to call an activity a vice and suppress it is that it reduces a person’s future happiness more than it increases his present happiness. Gruber and Koszegi (2001) show how a vice tax can increase a person’s welfare in a model of multiple selves with hyperbolic preferences across time. The present paper shows that an interself analogy of the Kaldor-Hicks compensation criterion can justify a vice ban whether preferences are hyperbolic or exponential, but subject to the caveat that the person has a binding constraint on borrowing.