Work is a subject with a long philosophical pedigree. Some of the most influential philosophical systems devote considerable attention to questions concerning who should work, how they should work, and why. For example, in the ideally just city outlined in the Republic, Plato proposed a system of labor specialization, according to which individuals are assigned to one of three economic strata, based on their inborn abilities: the laboring or mercantile class, a class of auxiliaries charged with keeping the peace and defending the city, or the ruling class of ‘philosopher-kings’. Such a division of labor, Plato argued, will ensure that the tasks essential to the city’s flourishing will be performed by those most capable of performing them.