 The focus on incomparability can be motived by its possible significance for rational choice. Comparing alternatives are central for rational choice, we want to know what alternative is the best, and thus examples of incomparability are taken to be a threat to rational decision-making. Incommensurability on the other hand is mostly of theoretical interest. The possibility of incommensurable values introduces restrictions for normative theories, in the sense that they should not assume that all values can be represented on the same cardinal scale. The focus on incomparability can thus be justified by referring to its relation to practical reason and rational choice.