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)

This essay is an introductory overview of the considerations in favor of epistemic infinitism, the view that the demands of justification are that one must have non-terminating series of reasons for one's beliefs if they are to be knowledge.

The regress problem -- Infinitism defended -- Metaepistemic varieties of epistemic infinitism -- Foundationalism, infinitism, and the given -- Argumentation and anti-dogmatism.

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.

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

Today it is generally assumed that epistemic justification comes in degrees. The consequences, however, have not been adequately appreciated. In this paper we show that the assumption invalidates some venerable attacks on infinitism: once we accept that epistemic justification is gradual, an infinitist stance makes perfect sense. It is only without the assumption that infinitism runs into difficulties.

In an earlier paper we have shown that a proposition can have a well-defined probability value, even if its justification consists of an infinite linear chain. In the present paper we demonstrate that the same holds if the justification takes the form of a closed loop. Moreover, in the limit that the size of the loop tends to infinity, the probability value of the justified proposition is always well-defined, whereas this is not always so for the infinite linear chain. This (...) suggests that infinitism sits more comfortably with a coherentist view of justification than with an approach in which justification is portrayed as a linear process. (shrink)

This paper is a response to Peter Klein's “Human Knowledge and the Infinite Progress of Reasoning” (also in this issue of this journal). After briefly discussing what Klein says about the requirement, for doxastic justification, that a belief be formed in the right way, I'll make the following three points: Klein's solution to the regress problem isn't an infinitist solution, Klein's position on doxastic justification faces a troubling dilemma, and Klein's objection to foundationalism fails.

One way to solve the epistemic regress problem would be to show that we can acquire justification by means of an infinite regress. This is infinitism. This view has not been popular, but Peter Klein has developed a sophisticated version of infinitism according to which all justified beliefs depend upon an infinite regress of reasons. Klein's argument for infinitism is unpersuasive, but he successfully responds to the most compelling extant objections to the view. A key component of his position is (...) his claim that an infinite regress is necessary, but not sufficient, for justified belief. This enables infinitism to avoid a number of otherwise compelling objections. However, it commits infinitism to the existence of an additional feature of reasons that is necessary and, together with the regress condition, sufficient for justified belief. The trouble with infinitism is that any such condition could account for the connection between justification and truth only by undermining the rationale for the regress condition itself. (shrink)

Foundationalist, Coherentist, Skeptic etc., have all been united in one respect--all accept epistemic justification cannot result from an unending, and non-repeating, chain of reasons. Peter Klein has recently challenged this minimal consensus with a defense of what he calls "Infinitism"--the position that justification can result from such a regress. Klein provides surprisingly convincing responses to most of the common objections to Infinitism, but I will argue that he fails to address a venerable metaphysical concern about a certain type of regress. (...) My conclusion will be that until Klein answers these metaphysical worries he will not have restored Infinitism as a viable option in epistemology. (shrink)

In ‘Infinitism Regained’, Jeanne Peijnenburg argues for a version of infinitism wherein ‘beliefs may be justified by an infinite chain of reasons that can be actually completed’. I argue that Peijnenburg has not successfully argued for this claim, but rather has shown that certain infinite series can be computed.

In a recent paper, Jeanne Peijnenburg and David Atkinson [ Studia Logica , 89(3):333-341 (2008)] have challenged the foundationalist rejection of infinitism by giving an example of an infinite, yet explicitly solvable regress of probabilistic justification. So far, however, there has been no criterion for the consistency of infinite probabilistic regresses, and in particular, foundationalists might still question the consistency of the solvable regress proposed by Peijnenburg and Atkinson.

The purpose of this paper is to explain how infinitism—the view that reasons are endless and non-repeating—solves the epistemic regress problem and to defend that solution against some objections. The first step is to explain what the epistemic regress problem is and, equally important, what it is not. Second, I will discuss the foundationalist and coherentist responses to the regress problem and offer some reasons for thinking that neither response can solve the problem, no matter how they are tweaked. Then, (...) I want to present the infinitist solution to the problem and defend it against some of the well known objections to it. (shrink)

Consider the following process of epistemic justification: proposition $E_{0}$ is made probable by $E_{1}$ which in turn is made probable by $E_{2}$ , which is made probable by $E_{3}$ , and so on. Can this process go on indefinitely? Foundationalists, coherentists, and sceptics claim that it cannot. I argue that it can: there are many infinite regresses of probabilistic reasoning that can be completed. This leads to a new form of epistemic infinitism.

Klein’s account of epistemic justification, infinitism, supplies a novel solution to the regress problem. We argue that concentrating on the normative aspect of justification exposes a number of unpalatable consequences for infinitism, all of which warrant rejecting the position. As an intermediary step, we develop a stronger version of the ‘finite minds’ objection.

I evaluate two new objections to an infinitist account of epistemic justification, and conclude that they fail to raise any new problems for infinitism. The new objections are a refined version of the finite-mind objection, which says infinitism demands more than finite minds can muster, and the normativity objection, which says infinitism entails that we are epistemically blameless in holding all our beliefs. I show how resources deployed in response to the most popular objection to infinitism, the original finite-mind objection, (...) can be redeployed to address the two new objections. (shrink)

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 degrees and can be complete. This paper demonstrates foundationalism's ample resources for explaining both features.Section II clarifies the debate's (...) key terms. Section III recounts how infinitism explains the two crucial features. Section IV presents Fantl's argument .. (shrink)

This paper critically evaluates the regress argument for infinitism. The dialectic is essentially this. Peter Klein argues that only an infinitist can, without being dogmatic, enhance the credibility of a questioned non-evident proposition. In response, I demonstrate that a foundationalist can do this equally well. Furthermore, I explain how foundationalism can provide for infinite chains of justification. I conclude that the regress argument for infinitism should not convince us.

Any satisfactory epistemology must account for the distinction between propositional and doxastic justification. Can infinitism account for it? Proposals to date have been unsatisfactory. This paper advances a new infinitist account of the distinction. The discussion proceeds as follows. Section 1 sets the stage. Section 2 presents Peter Klein's account. Section 3 raises a problem for Klein's account and suggests an improvement. Section 4 raises a further challenge. Sections 5 to 7 consider several unsuccessful attempts to meet the challenge. Section (...) 8 presents my new proposal, which can meet the challenge. Section 9 concludes the discussion. (shrink)