We study the interplay among imperfect memory, limited commitment, and theft, in an environment that can support monetary exchange and credit. Imperfect memory makes money useful, but it also permits theft to go undetected, and therefore provides lucrative opportunities for thieves. Limited commitment constrains credit arrangements, and the constraints tend to tighten with imperfect memory, as this mitigates punishment for bad behavior in the credit market. In spite of the fact that theft is a deadweight loss, theft in anonymous transactions can discipline credit market behavior, and can therefore be a good thing. We show that the Friedman rule is in general not feasible, or not optimal if it is feasible, and that there are conditions under which theft exists at the optimum.
