Epistemic Encroachment

Clayton Littlejohn (Australian Catholic University)

Impurists about knowledge believe that pragmatic encroachment is possible (e.g., that it might be possible that the evidential support we might have for our beliefs is insufficient given the potential costs of our acting on a mistaken belief even if that evidential support might have been adequate for an agent considering a different set of options or possible outcomes (Fantl and McGrath 2009, Owens 2000)). The idea that practical factors and considerations about what might be rational for an agent to choose might impose constraints on the scope of what she might know is controversial. I shall argue that the most familiar and influential impurist views are mistaken. These impurist views must be mistaken because they are incompatible with something I've dubbed "epistemic encroachment". Epistemic encroachment occurs when considerations about what we know (or, perhaps, rationally believe) impose constraints on what might rationally be chosen. Epistemic encroachment makes sense of some seemingly robust but puzzling intuitions about choice that, I shall argue, our impurists about knowledge cannot make sense of given their distinctive views about the relationships between belief, credence, and choice. (Epistemic encroachment is also something that we might have tacitly assumed to be possible if we hold wooly non-consequentialist views.) Because epistemic encroachment is incompatible with impurism about knowledge, our impurists need to moderate their ambitions and recognise that purism must be true of some epistemically important state or relation like knowledge.