On having no reason: dogmatism and Bayesian confirmation

Abstract

Recently in epistemology a number of authors have mounted Bayesian objections to dogmatism. These objections depend on a Bayesian principle of evidential confirmation: Evidence E confirms hypothesis H just in case Pr(H|E) > Pr(H). I argue using Keynes' and Knight's distinction between risk and uncertainty that the Bayesian principle fails to accommodate the intuitive notion of having no reason to believe. Consider as an example an unfamiliar card game: at first, since you're unfamiliar with the game, you assign credences based on the indifference principle. Later you learn how the game works and discover that the odds dictate you assign the very same credences. Examples like this show that if you initially have no reason to believe H, then intuitively E can give you reason to believe H even though Pr(H|E) ≤ Pr(H). I show that without the principle, the objections to dogmatism fail.Keywords Epistemology · Bayesianism · Confirmation · Evidence · Foundationalism · Dogmatism Epistemology concerns both the nature of epistemic justification but also the lack thereof. On many understandings of epistemic justification, justification requires reasons; epistemologists are therefore also interested in the notion of having no reason to believe that P. It is this intuitive notion that I examine in this paper.Recently in epistemology there has been a resurgence of interest in applying formal methods to epistemological problems. To evaluate these applications we need a clear understanding of the ingredient intuitive epistemic notions, like having no reason. For instance, Bayesian epistemology operates under the assumption that rational belief and evidential confirmation are successfully modeled using Bayesian probability theory.

Perceptual Justification and the Cartesian Theater

“…See, e.g., (Brogaard, 2013), (Brown, 2013), (Cohen, 2010), (Cullison, 2010), (Huemer, 2006 and, (Jehle 5 and Weatherson, 2012), (Kung, 2010), (Lycan, 2013), (Moretti, 2015), (Pollock and Cruz, 1999), (Pryor, 2000 and, (Silins, 2008), (Tucker, 2010 and, (Weatherson, 2007), and (Wedgwood, 2013), among many others. Note that while anti-Cartesianism is often coupled with a Moorean reply to the skeptic, this is not something I build in to the view.…”

“…25 E.g., (Vogel, 2014). 26 E.g., (Cohen, 2010), (Jehle and Weatherson, 2012), (Kung, 2010), (Moretti, 2015), (Pryor, MS and 2013), 27 (Vogel, 2014), and (Weatherson, 2007).…”

In defence of dogmatism

“…White's objections have impressed many epistemologists and led some to respond. For instance, Pryor (manuscript), Weatherson (2007) and Kung (2010) all suggest ways to revise the Bayesian framework to accommodate the intuitions of the dogmatist. 15 In contrast with revisionary responses of this type, Silins (2007) argues that White hasn't actually shown that DG and Bayesianism are incompatible.…”

“…26 For example, Pryor (manuscript) states that the situations in which dogmatism is meant to apply to respond to the perceptual sceptic -so, presumably, the typical situations adduced by the perceptual sceptic -are those in which the epistemic subjects can conceive of some non-perceiving alternative sh 'but are wholly uninformed about it' (5, my emphasis). Kung (2010) describes the same situations as those in which 'the subject has no [default] reason to believe any skeptical alternative…”

Seemings and Justification: An Introduction

“…For example, a dogmatist might argue that justification to have a low credence in the proposition I'm not being deceived has far more devastating consequences when it is risky than uncertain, when it is based on evidence than ignorance. Kung's (2010) attempt to exploit the distinction between risk and uncertainty is especially modest, because, like the approach in the previous sub-section, it can assume the classical Bayesian formalism for the sake of argument. His goal is to explain how, from within the classical Bayesian framework, one might try to model the difference between risk and uncertainty in a way that a dogmatist will find appealing.…”