Epistemic infinitism is the view that infinite series of inferential relations are productive of epistemic justification. Peirce is explicitly infinitist in his early work, namely his 1868 series of articles. Further, Peirce's semiotic categories of firsts, seconds, and thirds favors a mixed theory of justification. The conclusion is that Peirce was an infinitist, and particularly, what I will term an impure infinitist. However, the prospects for Peirce's infinitism depend entirely on the prospects for Peirce's early semantics, which are not good. (...) Peirce himself revised the semantic theory later, and in so doing, it seems also his epistemic infinitism. (shrink)

I will assume here the defenses of epistemic infinitism are adequate and inquire as to the variety standpoints within the view. I will argue that infinitism has three varieties depending on the strength of demandingness of the infinitist requirement and the purity of its conception of epistemic justification, each of which I will term strong pure, strong impure, and weak impure infinitisms. Further, I will argue that impure infinitisms have the dialectical advantage.

The Regress: Knowledge, we like to suppose, is essentially a rational thing: if I claim to know something, I must be prepared to back up my claim by statingmy reasons for making it;and if my claim is to be upheld, my reasons must begood reasons. Now suppose I know that Q; and let my reasons be conjunctively contained in the proposition that R. Clearly, I must believe that R ;equally clearly, I must know that R . Thus if I know (...) that Q, I know that R. But if I know that R, then I must have my reasons, R' for holding R; and, by the same argument, I mustknow that R'. And if R', then R”; and so on, ad infinitum. (shrink)

What follows is a taxonomy of arguments that regresses of inferential justification are vicious. They fall out into four general classes: conceptual arguments from incompleteness, conceptual arguments from arbitrariness, ought-implies-can arguments from human quantitative incapacities, and ought-implies can arguments from human qualitative incapacities. They fail with a developed theory of "infinitism" consistent with valuational pluralism and modest epistemic foundationalism.