 Aristotle’s idea of justice as proportional equality contains a fundamental insight. The idea offers a framework for a rational argument between egalitarian and non-egalitarian ideas of justice, its focal point being the question of the basis for an adequate equality (Hinsch 2003). Both sides accept justice as proportional equality. Aristotle’s analysis makes clear that the argument involves those features that decide whether two persons are to be considered equal or unequal in a distributive context.