A priori knowledge and justification, recent work on

The recent discussion of the a priori has involved some controversies about the concept of a priori justification or warrant, but has focused mainly on the central issue of whether such justification exists at all, together with the further issues pertaining to its nature and scope should it exist. (Since a priori knowledge can be understood as knowledge whose justification is a priori, it will suffice to focus here on justification.) While there are other views as well, the main contending positions are: (1) the recently reinvigorated moderate rationalist view that a priori justification genuinely exists and is not limited to claims that are matters of definition or meaning; (2) a strong version of empiricism (hereafter referred to here as radical empiricism), deriving from W.V. Quine, that denies the existence of a priori justification of any sort; and (3) an older and less extreme version of empiricism (hereafter referred to as moderate empiricism) that holds both that there is genuine a priori justification but also that it extends only to propositions that are merely matters of definition or meaning and thus which are analytic in character.