Abstract

Two criteria, one for distributive and one for commutative justice are formulated, the latter applying to cases of free cooperation. Both criteria follow Aristotle's idea of proportional equality which in the first case is equality in the fulfillment of legitimate claims, in the second case equality of the gains derived from cooperation. The theory of social welfare functions is employed in the definition of the two criteria, but such functions are applied only to morally or legally justified interests. A theory of justice only has to say how to satisfy conflicting legitimate claims, it is argued, but not what interests are justified in some given context.