The significance of value additivity

Whether value is “additive,” that is, whether the value of a whole must equal the sum of the values of its parts, is widely thought to have significant implications in ethics. For example, additivity rules out “organic unities,” and is presupposed by “contrast arguments.” This paper reconsiders the significance of value additivity. The main thesis defended is that it is significant only for a certain class of “mereologies”, roughly, those in which both wholes and parts are “complete”, in the sense that they can exist independently. For example, value additivity is significant in the case of a mereology of material objects, but not in the case of a mereology of propositions.