Rational Belief

This chapter generalizes the modal theory of subjective reasons to the epistemic domain and combines it with the first-order commitment that truth is the sole right-maker for belief. The result is a modal account of epistemic rationality, according to which there is a safety condition on rational belief distinct from but mirroring the more familiar safety condition on knowledge. The chapter shows that the account delivers plausible closure principles on rational belief and offers a straightforward resolution of the lottery paradox. It also explores the implications of the view for whether it is rational to believe necessary propositions, preface propositions, and Moorean propositions.

Applications

To earn their keep, theories of justification must be shown to have fruitful applications and to provide the means to address well-known puzzles and paradoxes. It is argued that the present account of justification does very well on this score. Not only does it prove amenable to the idea that standards for knowledge and justification may shift, it allows for an explanation of why they shift in tandem. It lends itself to a justificationist conception of the rules that may guide the formation of beliefs, to the extent that these beliefs aspire to be knowledgeable. The present account moreover affords principled solutions to the preface paradox, the lottery paradox, the related but distinct lottery puzzle, and a more recent sceptical challenge targeting doxastic justification.

Attributing Knowledge

The word “know” is revealed as vague, applicable to fallible agents, factive, and criterion-transcendent. It is invariant in its meaning across contexts and invariant relative to different agents. Only purely epistemic properties affect its correct application—not the interests of agents or those who attribute the word to agents. These properties enable “know” to be applied correctly—as it routinely is—to cognitive agents ranging from sophisticated human knowers, who engage in substantial metacognition, to various animals, who know much less and do much less, if any, metacognition, to nonconscious mechanical devices such as drones, robots, and the like. These properties of the word “know” suffice to explain the usage phenomena that contextualists and subject-sensitive invariantists invoke to place pressure on an understanding of the word that treats its application as involving no interests of agents, or others. It is also shown that the factivity and the fallibilist-compatibility of the word “know” explain Moorean paradoxes, the preface paradox, and the lottery paradox. A fallibility-sensitive failure of knowledge closure is given along with a similar failure of rational-belief closure. The latter explains why rational agents can nevertheless believe A and B, where A and B contradict each other. A substantial discussion of various kinds of metacognition is given—as well as a discussion of the metacognition literature in cognitive ethology. An appendix offers a new resolution of the hangman paradox, one that turns neither on a failure of knowledge closure nor on a failure of KK.

Profiling and Proof: Are Statistics Safe?

Many theorists hold that outright verdicts based on bare statistical evidence are unwarranted. Bare statistical evidence may support high credence, on these views, but does not support outright belief or legal verdicts of culpability. The vignettes that constitute the lottery paradox and the proof paradox are marshalled to support this claim. Some theorists argue, furthermore, that examples of profiling also indicate that bare statistical evidence is insufficient for warranting outright verdicts.I examine Pritchard's and Buchak's treatments of these three kinds of case. Pritchard argues that his safety condition explains the insufficiency of bare statistical evidence for outright verdicts in each of the three cases, while Buchak argues that her treatment of the distinction between credence and belief explains this. In these discussions the three kinds of cases – lottery, proof paradox, and profiling – are treated alike. The cases are taken to exhibit the same epistemic features. I identity significant overlooked epistemic differences amongst these three cases; these differences cast doubt on Pritchard's explanation of the insufficiency of bare statistical evidence for outright verdicts. Finally, I raise the question of whether we should aim for a unified explanation of the three paradoxes.

Paradoxes, epistemic

The four primary epistemic paradoxes are the lottery, preface, knowability, and surprise examination paradoxes. The lottery paradox begins by imagining a fair lottery with a thousand tickets in it. Each ticket is so unlikely to win that we are justified in believing that it will lose. So we can infer that no ticket will win. Yet we know that some ticket will win. In the preface paradox, authors are justified in believing everything in their books. Some preface their book by claiming that, given human frailty, they are sure that errors remain. But then they justifiably believe both that everything in the book is true, and that something in it is false. The knowability paradox results from accepting that some truths are not known, and that any truth is knowable. Since the first claim is a truth, it must be knowable. From these claims it follows that it is possible that there is some particular truth that is known to be true and known not to be true. The final paradox concerns an announcement of a surprise test next week. A Friday test, since it can be predicted on Thursday evening, will not be a surprise yet, if the test cannot be on Friday, it cannot be on Thursday either. For if it has not been given by Wednesday night, and it cannot be a surprise on Friday, it will not be a surprise on Thursday. Similar reasoning rules out all other days of the week as well; hence, no surprise test can occur next week. On Wednesday, the teacher gives a test, and the students are taken completely by surprise.