Cognition and Value Incommensurability

The chapter reviews distinct ways in which values are “incommensurable,” highlighting situations in which ends are truly incomparable, while noting that ends are also described as incommensurable when one end has lexical priority over other possible ends, when the value of the ends cannot be expressed in some single reduced form, and when there is particular reason to worry that decision makers who try to reduce the value of all ends to a single metric will overvalue ends that can most readily be evaluated. The chapter especially explores the implications of both Massive Modularity and F&F theory for the debate over whether ends are descriptively incommensurable. MM theorists could explain why people subjectively feel that certain ends are incommensurable; the intuition to take actions one ultimately does not take, because they cannot be taken if one is to take a more “urgent” action, is not obliterated, but “lives on” in its own module. F&F scholars model “pseudo-incommensurability”—the use of trumping rules that categorically forbid making trade-offs—because they believe that most cognition involves similar trumping rules.