We develop a theoretical model in which each individual is, in some ultimate sense, motivated by purely egoistic satisfaction derived from the goods accruing to him, but there is an implicit social contract such that each performs duties for the others in a way that enhances the satisfaction of...

We demonstrate that a rank-preserving transfer from a richer individual to a poorer individual can exacerbate income inequality (when inequality is measured by the Gini coefficient). This happens when individuals’ preferences depend negatively not only on work time (effort) but also on low...