Abstract

The use of dispositions has been put into question many times in the philosophical literature, especially with regards to how dispositional attributions can be justified. Yet, dispositions are an important part not only of our everyday talk but also of our scientific practices. In this paper, we develop an argument that infers the epistemic justification of dispositional talk from itsindispensability for carrying out basic epistemological projects, and we apply it to the use of dispositions in evolutionary biology. For doing this, we first advocate for a function-based strategy for the epistemic justification of dispositional attributions. We next review the functional role of some key dispositional notions in evolutionary biology, such as fitness and evolvability. Then, we show that alternative non-dispositional substitutes of these dispositions fail to fulfill their roles to the same degree. We conclude that the use of dispositions is justified in evolutionary biology.