Credal accuracy and knowledge

Synthese (2022) 200:163 https://doi.org/10.1007/s11229-022-03636-8 ORIGINAL RESEARCH Credal accuracy and knowledge Robert Weston Siscoe1 Received: 6 November 2021 / Accepted: 23 February 2022 © The Author(s) 2022 Abstract Traditional epistemologists assumed that the most important doxastic norms were rational requirements on belief. This orthodoxy has recently been challenged by the work of revolutionary epistemologists on the rational requirements on credences. Revolutionary epistemology takes it that such contemporary work is important precisely because traditional epistemologists are mistaken—credal norms are more fundamental than, and determinative of, belief norms. To make sense of their innovative project, many revolutionary epistemologists have also adopted another commitment, that norms on credences are governed by a fundamental accuracy norm. Unfortunately for the revolutionary epistemologist, it has been difficult to define a measure of accuracy while maintaining that credal norms are more basic than belief norms. In this paper, I criticize one such proposal for measuring accuracy, that the accuracy of our credences should be assessed in terms of what we know, arguing that this picture ultimately cannot vindicate the revolutionary approach. Keywords Knowledge · Epistemic possibility · Rational norms · Justified belief · Credal accuracy 1 Introduction Epistemologists traditionally took it that beliefs were the most important doxastic attitude to which rational norms applied. For much of epistemology’s history, this was because belief norms were the only ones which were explicitly theorized. Thus, consciously or unconsciously, traditional epistemology held that epistemic norms were at their most fundamental norms on belief. Recently, however, attention has shifted to the rationality of credence, with many claiming that rational credences are more fundamental than rational beliefs. These revolutionary epistemologists thus advocate a turn to Credence First accounts of the rationality of belief: B Robert Weston Siscoe 1 University of Cologne, Cologne, Germany 0123456789().: V,-vol 123 163 Page 2 of 13 Synthese (2022) 200:163 Credence First The rational norms for belief completely or partially depend on and are determined by the rational norms for credence, and thus the norms for credence are more fundamental. David Christensen exemplifies this view when he expresses doubt that belief is “subject to interesting rational constraints beyond those affecting degrees of confidence.”1 On this view, the foundational theoretical work is discovering the norms that govern the rationality of credence, revealing one of the central projects of traditional epistemology, discovering the norms on rational belief apart from norms on credences, to be sterile. Despite the advent of revolutionary epistemology, in keeping with traditional epistemology, many instead advocate the Belief First program: Belief First Norms on belief are more fundamental than the norms governing credence. Credal norms in fact depend on belief norms, and thus the recent spate of interest in norms on credences does not threaten the relevance of research programs and theories concerning the rationality of belief.2 Credence First and Belief First do not, however, exhaust the logical space, for it could be that there is not an interesting dependence relationship in either direction between belief norms and credal norms. Thus, even more recently than the advent of revolutionary epistemology, there have been those who have advocated for this very sort of Independence: Independence While there are norms on both beliefs and credences, these norms do not have any dependence relationships. Lara Buchak illustrates Independence, claiming, “It turns out we need belief, and its accompanying epistemology, precisely because there is a domain in which our norms involving beliefs are sensitive to the kinds of evidential connections that belief tracks but credence does not.”3 On this view, investigation into the norms governing belief and credence can carry on separately, perhaps with some interesting comparative insights, but nevertheless as distinct endeavors. My position is that the accuracy approach adopted by many advocates of Credence First is still yet to make good on its claim to upend traditional theorizing about belief. This is because, on one of the most prominent ways of making sense of credal accuracy, the rationality of credences does not end up being more fundamental than the rationality of belief.4 In Sect. 2, I introduce the accuracy approach to credal norms, 1 See Christensen (2004), p. 99. For a similar view, see Jeffrey (1970, 1992), though Jeffrey tends towards an eliminativist view of belief and thus also of norms on belief. 2 Harman (1986) comes closest to explicitly adopting this view, arguing that reasoning requires principles of belief revision rather than principles that regulate credences (pp. 21–23 and 104). Holton (2014) holds that limited creatures like us need beliefs rather than credences for practical deliberation (pp. 13–14). 3 See Buchak (2014), p. 296. Others that endorse Independence include Frankish (2004, 2009), Ross and Schroeder (2014), Sturgeon (2008), Weatherson (2014), and Wedgwood (2012). 4 Even though many of the epistemologists that emphasize accuracy fall into the Credence First camp, this is not inevitable. There have been a number of recent proposals, for example, that have explored the 123 Synthese (2022) 200:163 Page 3 of 13 163 showing in Sect. 3 that there is still an open question concerning which worlds should be used to measure credal accuracy. According to a popular proposal by Leitgeb and Pettigrew (2010), the rationality of credences is determined by the worlds that are epistemically possible for an epistemic agent—the worlds that are not ruled out by what an agent knows. I argue, however, in Sects. 4 and 5, that an account that is based in knowledge does not result in a Credence First account. If it really is the case, as the revolutionary epistemologist would have us believe, that discussions of justified belief are besides the point at best and a waste of time at worst, then leaving behind the defunct research program of traditional epistemology is a priority for making progress on what rationality requires. The argument advanced in this paper shows that such a dismissal of the traditional approach is too quick, and this because it is not yet clear how to determine the rationality of credences while also taking credal norms to be the most fundamental epistemic norms. Before we begin, it should be noted that it is possible to understand the fundamentality claims of the preceding positions in two senses. One can think that, metaphysically speaking, beliefs just are credences of a certain sort, or vice versa, that credences are a certain kind of belief, and thus that beliefs or credences are descriptively more fundamental. It is also possible t (...truncated)