In his Politics VI 3, 1318a–b, Aristotle discusses constitutional procedures for achieving justice in a society where its classes have different views on it. He ana- lyzes the case of a society consisting in two groups, the poor and the rich, each hold- ing a specific understanding of justice (democratic or oligarchic). In this paper we give, first, a non-formal summary of this section of Politics. Then we approach it in the framework of social choice theory and argue that a social rule for selecting between alternatives may be extracted from it. As Aristotle argued, this rule is con- sistent with the views on justice and equality of the supporters of both democracy and oligarchy. Finally, we study its properties, as well as some extensions of it when multiple classes are allowed or more than two alternatives are present.
