Abstract: Martin Davies explores a solution to a reductio ad absurdum argument template, one instance of which has the conclusion that we can know the proposition ‘someone has interacted with water’ a priori. Davies argues that there are limitations on the transmission of warrant across a priori entailments, limitations that instances of such an argument template necessarily flout.

Keywords: Martin Davies, entailment, externalism, Reductio ad absurdum, transmission, warrant,