Default Assumption, Hinge Commitment and the Closure Principle

This paper focuses on a potential problem with Sosa’s theory of default assumption, viz., the alleged incompatibility of this theory with the closure principle. Given the similarity between the notion of default assumption and Wittgenstein’s notion of hinge commitment, I suggest that two influential hinge epistemologies including Wright’s entitlement theory and Pritchard’s non-belief theory provide resources for possible solutions to the problem. I argue that default assumption should be classified as acceptance and hence as a non-doxastic propositional attitude. Sosa’s theory can deal with the apparent incompatibility with the closure principle by adopting the solution of the non-belief theory, while also avoiding problems affecting the latter view.