Should knowledge entail belief?

The appropriateness of S5 as a logic of knowledge has been attacked at some length in the philosophical literature. Here one particular attack based on the interplay between knowledge and belief is considered: Suppose that knowledge satisfies S5, belief satisfies KD45, and both the entailment property (knowledge implies belief) and positive certainty (if the agent believes something, she believes she knows it) hold. Then it can be shown that belief reduces to knowledge: it is impossible to have false beliefs. While the entialment property has typically been viewed as perhaps the least controversial of these assumptions, an argument is presented that it can plausibly be viewed as the culprit. More precisely, it is shown that this attack fails if we weaken the entailment property so that it applies only to objective (nonmodal) formulas, rather than to arbitrary formulas. Since the standard arguments in favor of the entailment property are typically given only for objective formulas, this observation suggests that care must be taken in applying intuitions that seem reasonable in the case of objective formulas to arbitrary formulas.Research sponsored in part by the Air Force office of Scientific Research (AFSC), under Contract F49620-91-C-0080. The United States Government is authorized to reproduce and distribute reprints for governmental purposes.     

Iterative and fixed point common belief

We define infinitary extensions to classical epistemic logic systems, and add also a common belief modality, axiomatized in a finitary, fixed-point manner. In the infinitary K system, common belief turns to be provably equivalent to the conjunction of all the finite levels of mutual belief. In contrast, in the infinitary monotonic system, common belief implies every transfinite level of mutual belief but is never implied by it. We conclude that the fixed- point notion of common belief is more powerful than the iterative notion of common belief.     

The virtues of epistemic conservatism

Although several important methodologies implicitly assume the truth of epistemic conservatism, the view that holding a belief confers some measure of justification on the belief, recent criticisms have led some to conclude that epistemic conservatism is an implausible view. That conclusion is mistaken. In this article, I propose a new formulation of epistemic conservatism that is not susceptible to the criticisms leveled at earlier formulations of epistemic conservatism. In addition to withstanding these criticisms, this formulation of epistemic conservatism has several benefits. First, this formulation has the benefits of earlier formulations of epistemic conservatism, that is to say it makes sense of our intuitions about justification in regard to both memory beliefs and beliefs for which we have forgotten our evidence. Second, it provides a good way of responding to the skeptic’s challenge concerning the possibility of possessing knowledge of the external world posed by the Alternative Hypotheses argument. Third, it provides responses to both forms of a new skeptical problem plaguing basic knowledge structure theories, the Problem of Easy Knowledge formulated by Stewart Cohen. I argue that given the many benefits of this formulation of epistemic conservatism and the fact that it is not vulnerable to the criticisms that undermine earlier formulations of epistemic conservatism, this formulation of epistemic conservatism is a plausible view to maintain.     

儿童在错误信念任务上的知识偏差

采用3种任务考查儿童在错误信念（FB）推理中是否存在知识偏差。被试为60名3—5岁幼儿,结果表明,对于3岁及4岁儿童来说,FB任务是存在知识偏差的。知识偏差的大小与年龄呈负相关关系,3岁与4岁、4岁与5岁儿童的知识偏差的大小均有显著差异。     

成人在错误信念任务上的表现

考察成人在错误信念(FB)任务上是否存在"知识偏差"效应。实验1重复Birch等的实验程序并未得到与之一致的结果,成人在FB任务上的表现不理想,且无"知识偏差"效应存在。实验2排除琴盒位置及颜色的突出性影响后,结果与实验1相似。成人在FB任务上的不佳表现与成人具有心理理论的事实相悖,说明把通过FB任务作为衡量心理理论的唯一评定标准有待商榷。     

Strong Completeness Theorems for Weak Logics of Common Belief

We show that several logics of common belief and common knowledge are not only complete, but also strongly complete, hence compact. These logics involve a weakened monotonicity axiom, and no other restriction on individual belief. The semantics is of the ordinary fixed-point type.     

Chisholm's Epistemic Principles

Abstract: An exposition and discussion of Chisholm's “epistemic principles.” These are compared with relevant views of Wilfrid Sellars and Richard Foley. A further comparison, with the approach favored by Descartes, is argued to throw light on the status of such principles.     

On Not Giving Up the World – Davidson and the Grounds of Belief

Abstract

What is the relation between our beliefs, or thoughts in general, and the perceptual experience of the world that gives rise to those beliefs? Donald Davidson is usually taken to have a well‐known answer to this question that runs as follows: while our beliefs are, at least in part, caused by our experience, such experience does not thereby count as providing a rational ground for those beliefs; our beliefs are thus evidentially grounded in other beliefs, but not in the experience that gives rise to them. John McDowell, among others, has challenged this Davidsonian picture on the grounds that it actually severs the connection between beliefs and their proper evidential grounds. Against such a view, this paper argues the Davidsonian position grounds belief in the specificity of our own locatedness in the world, and in the more general and prior embeddedness of belief in the world that is a part of the very concept of belief.     

Replies to commentators on <Emphasis Type="Italic">A Virtue Epistemology</Emphasis> (Oxford University Press, 2007)

Paul Boghossian discusses critically my account of intuition as a source of epistemic status. Stewart Cohen takes up my views on skepticism, on dreams, and on epistemic competence and competences and their relation to human knowledge. Hilary Kornblith focuses on my animal/reflective distinction, and, along with Cohen, on my comparison between how dreams might mislead us and how other bad epistemic contexts can do so. In this paper I offer replies to my three critics.

Précis of <Emphasis Type="Italic">A Virtue Epistemology</Emphasis> (Oxford University Press, 2007)

This is a summary of A Virtue Epistemology, the book that is the subject of this book symposium.     

错误信念任务中的知识偏差

有观点指出,年幼儿童在错误信念任务上的发展变化,不是发生了概念变化的质变,而是知识偏差的表现。知识偏差是指当我们尝试理解一个更不知情的观点时,不能忽略自己拥有的额外信息并受此影响而产生偏差的倾向。本文对知识偏差的含义及其在错误信念任务中可能产生的影响做了较为详细的综述和分析,并就在错误信念任务中消除知识偏差影响的可能性进行了探讨。