Abstract

Incommensurability is often introduced with the small improvement argument. Options A and B are shown to be incommensurable when it is neither the case that A is preferred to (or better than) B nor that B is preferred to (or better than) A, but a slightly improved version of A (A+) is still not preferred to B. Since A+ is preferred to A, but not to B, we must also conclude that it is also true that A and B are not indifferent (or equally good). Such incommensurable options seem incompatible with orthodox decision theory (and various forms of value theory) but options that obey the pattern described by this argument seem ubiquitous: my choice between lemon tarts and eclairs at my favourite pastry shop might exhibit this pattern, but so could my choice between jobs or careers. In trying to accommodate incommensurable options within various frameworks, philosophers have argued that we must preserve certain central features of the phenomenon. Among them is the supposed “hardness” of at least some incommensurable options: even if perhaps one would need to be a rather anxious gourmet to describe the choice between lemon tarts and eclairs as hard, the choice among careers could potentially be agonizing. However, it is not clear in which way choices among incommensurable options are “hard,” nor how and whether such hardness poses problems for the various accounts of incommensurable choices. To complicate matters, the deontic verdicts for choices between incommensurable options seem to be relatively straightforward: one appealing view is that in such circumstances I am rationally permitted to choose any option that is not worse than another option. This paper aims to provide a sharper formulation of at least a version of the hardness problem, to argue that various theories of incommensurability fail to account for the hardness of some incommensurable choices, and to propose that the theory of instrumental rationality I develop in Rational Powers in Action, aided by a Kantian insight, promises to provide an adequate explanation of the hardness of choice among incommensurable options.