The Pragmatic A Priori of C.I. Lewis

Abstract

A priori knowledge is a topic of much controversy in epistemology. Understanding how we can know the truth of certain statements without turning to empirical evidence is, however, a quintessential philosophical endeavor. An innovative account of the a priori was presented by the American pragmatist Clarence Irving Lewis. Lewis introduced the conception in his 1923 paper “A Pragmatic Conception of the A Priori”, and refined it into the cornerstone of his epistemological theory in “Mind and the World Order” (1929). Lewis turns the notion of a priori knowledge on this year. The pragmatic a priori is not universally privileged as was held by the traditional Cartesian and Leibnizian positions. Lewis maintains rather that a priori knowledge is always reflexive to a convention. Lewis’ elegant account does not, however, collapse into conventionalism or relativism. While a priori truths may vary across conventions, they are still privileged within a convention. Once a given convention is chosen, its a priori knowable truths hold fast, come what may. A demonstration of such variance can, for example, be given in comparing various consistent logics and competing hyperbolic geometries. Lewis maintains that in conjunction with the given element in experience, many conventions yield equally accurate knowledge. The fundamental a priori commitments adopted within a convention act as the grounds for veridicality. Thus judging veridicality across conventions is not possible. Choice of conceptual commitment is discernible only in terms of pragmatic criteria. This notion yields a kind of an ontological perspectivism not untypical to American pragmatism in general. In the present paper the central arguments for the pragmatic a priori are explored, contrasting them with classical notions where necessary. Lewis’ main arguments will be drawn especially from the 1923 introduction, and supported further by a wide corpus of his later writings. It is the purpose of the present paper to deliver a concise account of the pragmatic a priori, as well as to defend it as the most plausible account of a priori knowledge currently available.