Knowledge,reasoning, and deliberation

Epistemologists have become increasingly interested in the practical role of knowledge. One prominent principle, which I call PREMISE, states that if you know that p, then you are justified in using p as a premise in your reasoning. In response, a number of critics have proposed a variety of counter-examples. In order to evaluate these problem cases, we need to consider the broader context in which this principle is situated by specifying in greater detail the types of activity that the principle governs. I argue that if PREMISE is interpreted as governing deductive reasoning, then the examples lose their force. In addition, I consider the cases, discussed by Keith DeRose, where the subject is in more than one practical context at the same time. In order to account for these latter cases, we need to further specify the scope of PREMISE. I distinguish two ways of understanding PREMISE, as a knowledge-action principle and as a knowledge-deliberation principle. I conclude by arguing for the knowledge-deliberation version of the principle and by exploring what this principle says about the practical role of knowledge.     

The Reasoning View and Defeasible Practical Reasoning

According to the Reasoning View about normative reasons, facts about normative reasons for action can be understood in terms of facts about the norms of practical reasoning. I argue that this view is subject to an overlooked class of counterexamples, familiar from debates about Subjectivist theories of normative reasons. Strikingly, the standard strategy Subjectivists have used to respond to this problem cannot be adapted to the Reasoning View. I think there is a solution to this problem, however. I argue that the norms of practical reasoning, like the norms of theoretical reasoning, are characteristically defeasible, in a sense I make precise. Recognizing this property of those norms makes space for a solution to the problem. The resulting view is in a way analogous to the familiar defeasibility theory of knowledge, but it avoids a standard objection to that theory.     

Justification,sociality, and autonomy

Theories of epistemically justified belief have long assumed individualism. In its extreme, or Lockean, form individualism rules out justified belief on testimony by insisting that a subject is justified in believing a proposition only if he or she possesses first-hand justification for it. The skeptical consequences of extreme individualism have led many to adopt a milder version, attributable to Hume, on which a subject is justified in believing a proposition only if he or she is justified in believing that there is testimony in favor of the proposition deriving from a reliable source. I argue that this Humean individualism also leads to skepticism in a wide range of cases; it makes it impossible for a layperson to be justified on expert testimony. In addition, I argue that the apparent motivation for the Humean view, an insistence on intellectual autonomy in justification, does not succeed in motivating it. I then explore the contours of a collectivist view of justification on testimony, with special attention to the place of a subject's intellectual autonomy in such justification. I try to bring empirical results of the psychology of persuasion to bear on the epistemological issues.     

Prediction,Authority, and Entitlement in Shared Activity

Shared activity is often simply willed into existence by individuals. This poses a problem. Philosophical reflection suggests that shared activity involves a distinctive, interlocking structure of intentions. But it is not obvious how one can form the intention necessary for shared activity without settling what fellow participants will do and thereby compromising their agency and autonomy. One response to this problem suggests that an individual can have the requisite intention if she makes the appropriate predictions about fellow participants. I argue that implementing this predictive strategy risks derailing practical reasoning and preventing one from forming the intention. My alternative proposal for reconciling shared activity with autonomy appeals to the idea of acting directly on another's intention. In particular, I appeal to the entitlement one sometimes has to another's practical judgment, and the corresponding authority the other sometimes has to settle what one is to do.     

Thinking,Acting, Considering

According to a familiar (alleged) requirement on practical reason, one must believe a proposition if one is to take it for granted in reasoning about what to do. This paper explores a related requirement, not on thinking but on acting—that one must accept a goal if one is to count as acting for its sake. This is the acceptance requirement. Although it is endorsed by writers as diverse as Christine Korsgaard, Donald Davidson, and Talbot Brewer, I argue that it is vulnerable to counterexamples, in which agents act in light of ends that they do not accept but are still merely considering. For instance, a young professional may keep a job option open not because she definitely wants or intends to take it, but just because she is considering taking it. I try to show (1) that such examples are not easily resisted; (2) that they present challenges specifically for Brewer, Davidson, and especially Korsgaard; and (3) that the examples also raise fresh, non-partisan questions in action theory. What is considering, exactly? How could it fall short of acceptance while still guiding behaviour? How can we act for an end before thinking it through?     

Lotteries,Quasi-Lotteries,and Scepticism

I seem to know that I won't experience spaceflight but also that if I win the lottery, then I will take a flight into space. Suppose I competently deduce from these propositions that I won't win the lottery. Competent deduction from known premises seems to yield knowledge of the deduced conclusion. So it seems that I know that I won't win the lottery; but it also seems clear that I don't know this, despite the minuscule probability of my winning (if I have a lottery ticket). So we have a puzzle. It seems to generalize, for analogues of the lottery-proposition threaten almost all ordinary knowledge attributions. For example, my apparent knowledge that my bike is parked outside seems threatened by the possibility that it's been stolen since I parked it, a proposition with a low but non-zero probability; and it seems that I don't know this proposition to be false. Familiar solutions to this family of puzzles incur unacceptable costs—either by rejecting deductive closure for knowledge, or by yielding untenable consequences for ordinary attributions of knowledge or of ignorance. After canvassing and criticizing these solutions, I offer a new solution free of these costs.

Knowledge that p requires an explanatory link between the fact that p and the belief that p. This necessary but insufficient condition on knowledge distinguishes actual lottery cases from typical, apparently analogous ‘quasi-lottery’ cases. It does yield scepticism about my not winning the lottery and not experiencing spaceflight, but the scepticism doesn't generalize to quasi-lottery cases such as that involving my bike.     

Reducing structural-element salience on a source problem produces later success in analogical transfer: What role does source difficulty play?

Two experiments in reasoning by analogy were conducted to study the role of inducing source difficulty by reducing the salience of the source's structural elements. Three nonexclusive hypotheses were tested. According to the first, a difficult source problem improves analogical transfer because it increases the probability that the subject will notice the similarity between the source and the target. For example, errors made on both the source and the target can enhance the subject's awareness of the similarity between the two problems. According to the second hypothesis, a source that is difficult to solve is memorized better than an easier source. According to the third, source-problem difficulty affects the degree of abstractness in the representation of the solution elaborated by subjects. Experiment 1 showed that the higher frequency of spontaneous transfer between the source and the target when the source problem was difficult (Gick & McGarry, 1992) could be replicated in a cued-transfer situation. Experiment 2 showed that subjects given a difficult source, one in which the important element was not very salient, were better at categorizing isomorphic problems on the basis of structural features than were subjects given an easy source. The discussion deals with the implications of these results for the hypotheses tested and, more generally, for reasoning by analogy and education in general.     

Scepticism,defeasible evidence and entitlement

The paper starts by describing and clarifying what Williamson calls the consequence fallacy. I show two ways in which one might commit the fallacy. The first, which is rather trivial, involves overlooking background information; the second way, which is the more philosophically interesting, involves overlooking prior probabilities. In the following section, I describe a powerful form of sceptical argument, which is the main topic of the paper, elaborating on previous work by Huemer. The argument attempts to show the impossibility of defeasible justification, justification based on evidence which does not entail the (allegedly) justified proposition or belief. I then discuss the relation between the consequence fallacy, or some similar enough reasoning, and that form of argument. I argue that one can resist that form of sceptical argument if one gives up the idea that a belief cannot be justified unless it is supported by the totality of the evidence available to the subject—a principle entailed by many prominent epistemological views, most clearly by epistemological evidentialism. The justification, in the relevant cases, should instead derive solely from the prior probability of the proposition. A justification of this sort, that does not rely on evidence, would amount to a form of entitlement, in (something like) Crispin Wright’s sense. I conclude with some discussion of how to understand prior probabilities, and how to develop the notion of entitlement in an externalist epistemological framework.     

概率的不同表征对贝叶斯推理的影响的研究

该研究以贝叶斯推算、判断为实验任务,探讨了三种概率表征(百分比、自然频率、概率词)、三种概率规则认识水平对贝叶斯推理的影响,结果表明:1)概率词表征的贝叶斯推算实质是判断过程。2)在三种概率表征中,频率表征更适合于正确完成贝叶斯推理,但存在学科背景的差异。3)贝叶斯推理使用的策略有正确规则、错误规则、命题知识、概率简捷式、直觉和个人意愿六种。4)贝叶斯判断的正确率高于贝叶斯推算,个体在贝叶斯判断上使用的正确规则多于贝叶斯推算过程。     

The degree of epistemic justification and the conjunction fallacy

This paper describes a formal measure of epistemic justification motivated by the dual goal of cognition, which is to increase true beliefs and reduce false beliefs. From this perspective the degree of epistemic justification should not be the conditional probability of the proposition given the evidence, as it is commonly thought. It should be determined instead by the combination of the conditional probability and the prior probability. This is also true of the degree of incremental confirmation, and I argue that any measure of epistemic justification is also a measure of incremental confirmation. However, the degree of epistemic justification must meet an additional condition, and all known measures of incremental confirmation fail to meet it. I describe this additional condition as well as a measure that meets it. The paper then applies the measure to the conjunction fallacy and proposes an explanation of the fallacy.     

The Knower Paradox and Epistemic Closure

The Knower Paradox has had a brief but eventful history, and principles of epistemic closure (which say that a subject automatically knows any proposition she knows to be materially implied, or logically entailed, by a proposition she already knows) have been the subject of tremendous debate in epistemic logic and epistemology more generally, especially because the fate of standard arguments for and against skepticism seems to turn on the fate of closure. As far as I can tell, however, no one working in either area has emphasized the result I emphasize in this paper: the Knower Paradox just falsifies even the most widely accepted general principles of epistemic closure. After establishing that result, I discuss five of its more important consequences.     

Practical Modes of Presentation

The Intellectualist thesis that know‐how is a kind of propositional knowledge faces a simple problem: For any proposition p, it seems that one could know p without knowing how to do the activity in question. For example, it seems that one could know that w is a way to swim even if one didn't know how to swim oneself. In this paper I argue that this “sufficiency problem” cannot be adequately addressed by appealing to practical modes of presentation.     

Sleeping Beauty, evidential support and indexical knowledge: reply to Horgan

Terence Horgan defends the thirder position on the Sleeping Beauty problem, claiming that Beauty can, upon awakening during the experiment, engage in “synchronic Bayesian updating” on her knowledge that she is awake now in order to justify a 1/3 credence in heads. In a previous paper, I objected that epistemic probabilities are equivalent to rational degrees of belief given a possible epistemic situation and so the probability of Beauty’s indexical knowledge that she is awake now is necessarily 1, precluding such updating. In response, Horgan maintains that the probability claims in his argument are to be taken, not as claims about possible rational degrees of belief, but rather as claims about “quantitative degrees of evidential support.” This paper argues that the most plausible account of quantitative degree of support, when conjoined with any of the three major accounts of indexical thought in such a way as to plausibly constrain rational credence, contradicts essential elements of Horgan’s argument.     

Spontaneous Anomalystic Phenomena,Pragmatic Information and Formal Representations of Uncertainty

I discuss the application of the Model of Pragmatic Information to the study of spontaneous anomalystic mental phenomena like telepathy, precognition, etc. In these phenomena the most important effects are related to anomalous information gain by the subjects. I consider the basic ideas of the Model, as they have been applied to experimental anomalystic phenomena and to spontaneous phenomena that have strong physical effects, like poltergeist cases, highlighting analogies and differences. Moreover, I point out that in such cases we cannot assign a probability of being accepted to every proposition, and so we cannot use standard formulas for pragmatic information and other relevant measures. To overcome the problem, I propose that qualitative possibility theory could be used to describe the situation. In such theory, the confidence in a proposition is expressed using a scale. Basic concepts like epistemic states, belief revision, information gain, pragmatic information etc. are discussed in this frame. Finally an application to some specific cases is sketched.     

A Refutation of Cartesian Fallibilism

According to a doctrine that I call “Cartesianism”, knowledge – at least the sort of knowledge that inquirers possess – requires having a reason for belief that is reflectively accessible as such. I show that Cartesianism, in conjunction with some plausible and widely accepted principles, entails the negation of a popular version of Fallibilism. I then defend the resulting Cartesian Infallibilist position against popular objections. My conclusion is that if Cartesianism is true, then Descartes was right about this much: for S to know that p, S must have reasons for believing that p which are such that S can know, by reflection alone, that she has those reasons, and that she could not possibly have those reasons if p is not true. Where Descartes went wrong was in thinking that our ordinary, fallible, non‐theologically grounded sources of belief (e.g., perception, memory, testimony), cannot provide us with such reasons.     

Horgan on Sleeping Beauty

With the notable exception of David Lewis, most of those writing on the Sleeping Beauty problem have argued that 1/3 is the correct answer. Terence Horgan has provided the clearest account of why, contrary to Lewis, Beauty has evidence against the proposition that the coin comes up heads when she awakens on Monday. In this paper, I argue that Horgan’s proposal fails because it neglects important facts about epistemic probability.     

The Agent‐Relative Probability Threshold of Hope

Nearly all contributors to the philosophical analysis of hope agree that if an agent hopes that p, she both desires that p and assigns to p a probability which is greater than zero, but less than one. According to the widely‐endorsed Standard Account, these two conditions are also (jointly) sufficient for ‘hoping that’. Ariel Meirav has recently argued, however, that the Standard Account fails to distinguish hoping for a prospect from despairing of it – due to cases where two agents equally desire an outcome and assign to it the same probability, yet one hopes for the outcome while the other despairs of it. I argue, against Meirav, that these putative counterexamples depend crucially on the assumption – previously unquestioned – that the degree of probability necessary for hope is invariant across individuals. If the probability threshold is instead understood as agent‐relative, the difficulty disappears. Further, I argue that there is strong independent reason for taking the probability threshold of hope to be agent‐relative, based on similarities to the widely‐accepted agent‐relative probability thresholds of industriousness and risk aversion. And I conclude by noting how the agent‐relative modification to the Standard Account is better equipped than is Meirav's positive view to yield intuitive results. ¹      

Can probability theory explain why closure is both intuitive and prone to counterexamples?

Epistemic closure under known implication is the principle that knowledge of \(\varphi\) and knowledge of \(\varphi \rightarrow \psi\), together, imply knowledge of \(\psi\). This principle is intuitive, yet several putative counterexamples have been formulated against it. This paper addresses the question, why is epistemic closure both intuitive and prone to counterexamples? In particular, the paper examines whether probability theory can offer an answer to this question based on four strategies. The first probability-based strategy rests on the accumulation of risks. The problem with this strategy is that risk accumulation cannot accommodate certain counterexamples to epistemic closure. The second strategy is based on the idea of evidential support, that is, a piece of evidence supports a proposition whenever it increases the probability of the proposition. This strategy makes progress and can accommodate certain putative counterexamples to closure. However, this strategy also gives rise to a number of counterintuitive results. Finally, there are two broadly probabilistic strategies, one based on the idea of resilient probability and the other on the idea of assumptions that are taken for granted. These strategies are promising but are prone to some of the shortcomings of the second strategy. All in all, I conclude that each strategy fails. Probability theory, then, is unlikely to offer the account we need.     

Problems with persistence

A fundamental question in reasoning about change is, what information does a reasoning agent infer about later times from earlier times? I will argue that reasoning about change by an agent is to be modeled in terms of the persistence of the agent's beliefs over time rather than the persistence of truth and that such persistence is explained by pragmatic factors about how agents acquire information from other agents rather than by general principles of persistence about states of the world. AI accounts of persistence have focused on ‘closed world’ examples of change, in which the agent believes that the truth of a proposition is unaltered so long as he or she has no evidence that it has been changed. AI principles of persistence seem plausible in a closed world where one assumes the agent knows everything that is happening. If one drops the assumption of omniscience, however, the analysis of persistence is implausible. To get a good account of persistence and reasoning about change, I argue we should examine ‘open world’ examples of change, in which the agent is ignorant of some of the changes occurring in the world. In open world examples of change, persistence must be formulated, I argue, as a pragmatic principle about the persistence of beliefs. After elaborating my criticisms of current accounts of persistence, I examine how such pragmatic principles fare with the notorious examples of reasoning about action that have collectively characterized the so-called frame problem.     

The Decision-Theoretic Lockean Thesis

Abstract

Certain philosophers maintain that there is a ‘constitutive threshold for belief’: to believe that p just is to have a degree of confidence that p above a certain threshold. On the basis of this view, these philosophers defend what is known as ‘the Lockean Thesis’, according to which it is rational to believe that p just in case it is rational to have a degree of confidence that p above the constitutive threshold for belief. While not directly speaking to the controversy over the Lockean Thesis, this paper defends the general idea behind it—namely, the thesis that there is some threshold such that it is rational to believe that p if and only if it is rational to have a degree of confidence greater than that threshold. This paper identifies the threshold in question—not with the alleged constitutive threshold for belief—but with what I call ‘the practical threshold for rational belief’. Roughly, the thesis defended here is that it is rational to believe that p if and only if it is rational to have a degree of confidence that p that rationalizes engaging in certain types of practical reasoning.