A long time ago most economists would have limited themselves to stating that agreements should be individually rational and efficient and that selecting a specific agreement from that set depends on bargaining and negotiation power whatever that may be. Nowadays hardly any economist will argue...

Similar to welfare economics where with(out) interpersonal comparisons one defines unique (set-valued) welfare (Pareto) optima, we present a framework for one-person decision making where with(out) a prior probability distribution individual optimality prescribes usually a unique (set of)...