This essay discusses implications of incommensurability of values for justified decision-making, ethics and justice. Under particular conditions incommensurability of values causes what might be called ‘incomplete comparability’ of options. Some leading theorists interpret this in terms of ‘imprecise equality’ and ‘imprecise comparability.’ This interpretation is mistaken and conceals the implications of incommensurability for practical and ethical reasoning. The aim of this essay is to show that, in many cases, incommensurability prevents the assignment of determinate weights to competing values. This may (...) have problematic consequences for a complete and impartial justification of decisions concerning conflicting values to the extent that they depend on the need of weighing them. (shrink)