  John Stuart Mill ([1848] 1965, book 5, chap. 11, sect. 12) expresses the logic very clearly in his defense of laws to require maximum hours of work. He supposes that all workers would be better off if the workday were reduced from, say ten to nine hours a day for all, but that every individual worker would be better off working the extra hour if most others do not. The only way for them to benefit from the shorter workday, therefore, would be to make it illegal to work longer than nine hours a day.