This subjective process of sacrifice and gain within the individual psyche is by no means something secondary or imitative in relation to interindividual exchange. On the contrary, the give-and-take between sacrifice and attainment within the individual is the fundamental presupposition and, as it were, the essence of every two-sided exchange. The latter is only a subspecies of the former; that is, it is the sort in which the sacrifice is occasioned by the demand of another individual, whereas the sacrifice can be occasioned by things and their natural properties with the same sort of consequences for the actor.

Georg Simmel, on individuality and social…, loc. 226