Belief, credence, and evidence

Abstract

I explore how rational belief and rational credence relate to evidence. I begin by looking at three cases where rational belief and credence seem to respond differently to evidence: cases of naked statistical evidence, lotteries, and hedged assertions. I consider an explanation for these cases, namely, that one ought not form beliefs on the basis of statistical evidence alone, and raise worries for this view. Then, I suggest another view that explains how belief and credence relate to evidence. My view focuses on the possibilities that the evidence makes salient. I argue that this makes better sense of the difference between rational credence and rational belief than other accounts.

The relationship between belief and credence

“…On “strong dualism,” it may be possible to believe p and have a low credence in p, or believe the probability of p is high but have a low credence in p. In this, the extent to which beliefs, credences, and probability‐beliefs come apart is not fully captured by the reduction question. Jackson (2020) calls the question of how much belief and credence come apart the independence question . Thus, the metaphysics of belief and credence then includes (at least) three issues: ontology, reducibility, and independence (Figure 1).…”

“…On a third view, the norms for each attitude are independent: maybe the norms for credence are probabilistic coherence and updating by conditionalization, and the norms for belief are deductive consistency (Frankish, 2009, p. 80; Weisberg, 2015). Relatedly, several authors have argued that rational belief and rational credence are sensitive to different features of a body of evidence, so, for example, one could rationally have a high credence in p, but should not believe p (see Buchak, 2014; Friedman, 2013; Jackson, 2019c, Forthcoming; Smith, 2010b, 2016; Staffel, 2015). We will return to fundamentality later, but now examine arguably the most widely‐discussed normative connection between belief and credence: the Lockean thesis.…”

“…Thus, according to the traditional Lockean thesis, you should believe he stole the phone. However, many, including Buchak, insist that this is the wrong result: you should not believe that Jake stole your phone, as you do not have evidence that he in particular stole the phone (see Jackson, Forthcoming; Smith, 2010b; Staffel, 2015, 2019a). This is also supported by legal practices—we likely would not convict Jake of theft merely on the basis of a statistic (Enoch, Spectre, & Fisher, 2012; Gardiner, 2019).…”

“…A second reason to care about the relationship between belief and credence is because many debates in epistemology (e.g., permissivism, disagreement, pragmatic encroachment) look very different if the primary attitude of debate is belief or credence, and if a reductionist project is successful (Jackson, 2019a, 2020, Palmira, 2017). The relationship between belief and credence has implications for debates in epistemology, philosophy of mind, and beyond.…”

“… Defenses of the Lockean Thesis include Foley (1992, 1993, Chapter 4, 2009), Hawthorne and Bouvens (1999), Christensen (2004), Sturgeon (2008), Lin and Kelly (2013), Locke (2014), Easwaran (2016), Shear and Fitelson (2019), Dorst (2019), Thorn (Forthcoming). Arguments against the Lockean Thesis include Friedman (2013), Buchak (2014), Staffel (2015), Smith (2010a, 2016), Kelp (2017), Jackson (2019c, Forthcoming). …”