Foundationalism for Modest Infinitists

I Introduction

We find two main contemporary arguments for the infinitist theory of epistemic justification ('infinitism' for short): the regress argument(Klein 1999, 2005) and the features argument(Fantl 2003). I've addressed the former elsewhere (Turri 2009a). Here I address the latter.

Jeremy Fantl argues that infinitism outshines foundationalism because infinitism alone can explain two of epistemic justification's crucial features, namely, that it comes in degreesand can be complete. This paper demonstrates foundationalism's ample resources for explaining both features.

Section IIclarifies the debate's key terms. Section IIIrecounts how infinitism explains the two crucial features. Section IVpresents Fantl's argument that foundationalism cannot explain the two crucial features. Section V explains how foundationalism can explain the two crucial features. Section VI sums up.

II Terms and Requirements

Infinitismis the view that a proposition Q is epistemically justified for you just in case there is available to you an infinite series of non-repeating reasons that favors believing Q (Fantl 2003, 539). ¹ Foundationalismis the view that Q is epistemically justified for you just in case you have a series of non-repeating reasons that favors believing Q, terminating in a properly basic foundational reason 'that needs no further reason.' ²

I cannot here fully characterize epistemic justification, partly because doing so would beg important questions in the present context, but I may say this much. Epistemic justificationis the positive normative status needed for knowledge, closely associated with having evidence in favor of the truth of some claim, and typically contrasted with the practical justification, whether moral or prudential, involved in action. ³I shall refer to it simply as 'justification'.

Doubtless justification comes in degrees. You can obviously be more or less justified in accepting some claim. An adequate theory of justification must respect this, and 'explain why or show how' justification comes in degrees. Call this the degree requirement. Complete justificationis 'justification for which there is no higher degree' (Fantl 2003, 538), or otherwise put, 'that degree of justification that cannot be increased further' (Fantl 2003, 547). This contrasts with adequate justification, which is the minimal degree of justification required for knowledge. It is not plausible to identify adequate justification with complete justification. That justification can be complete is less obvious than that it comes in degrees. For the sake of argument, I grant that justification can be complete. As such, an adequate theory of justification must likewise explain why or show how justification can be complete. Call this the completeness requirement.

III How Infinitism Proposes to Meet the Requirements

Infinitists satisfy the degree requirement by pointing out that length comes in degrees, which justification may mirror. 'All else being equal, the longer your series of reasons for a proposition, the more justified it is for you' (Fantl 2003, 554).

Fantl offers the following analysis of complete justification: Q is completely justified for you just in case you have an infinite array of adequate reasons for Q (Fantl 2003, 558). Having an infinite array involves infinitely more than merely having an infinite series. To have an infinite array of reasons favoring Q, for each potential challenge to Q, or to any of the infinite reasons in the chain supporting Q, or to any of the inferences involved in traversing any link in the chain, you must have available a further infinite series of reasons. In a word, it requires having an infinite number of infinite chains.

This analysis of complete justification ensures that no proposition is ever completely justified for any of us. Fantl does not view this as a problem, because he intuits that although many propositions are adequately justified for us, none is completely justified.

There is an alternative view, however. It seems that we are justified in being absolutely certain of some claims. For example, I know for absolute certain that I exist, and that something exists. Furthermore, it is natural to suppose that we are completely justified when we know for absolute certain. So at least some claims would seem to be completely justified for us. If correct, this confounds Fantl...