Iterated Belief Change and the Recovery Axiom

The axiom of recovery, while capturing a central intuition regarding belief change, has been the source of much controversy. We argue briefly against putative counterexamples to the axiom—while agreeing that some of their insight deserves to be preserved—and present additional recovery-like axioms in a framework that uses epistemic states, which encode preferences, as the object of revisions. This makes iterated revision possible and renders explicit the connection between iterated belief change and the axiom of recovery. We provide a representation theorem that connects the semantic conditions we impose on iterated revision and our additional syntactical properties. We show interesting similarities between our framework and that of Darwiche–Pearl (Artificial Intelligence 89:1–29 1997). In particular, we show that intuitions underlying the controversial (C2) postulate are captured by the recovery axiom and our recovery-like postulates (the latter can be seen as weakenings of (C2)). We present postulates for contraction, in the same spirit as the Darwiche–Pearl postulates for revision, and provide a theorem that connects our syntactic postulates with a set of semantic conditions. Lastly, we show a connection between the contraction postulates and a generalisation of the recovery axiom. Portions of this paper were originally presented at ECAI 2002.     

Gricean Belief Change

One of the standard principles of rationality guiding traditional accounts of belief change is the principle of minimal change: a reasoner's belief corpus should be modified in a minimal fashion when assimilating new information. This rationality principle has stood belief change in good stead. However, it does not deal properly with all belief change scenarios. We introduce a novel account of belief change motivated by one of Grice's maxims of conversational implicature: the reasoner's belief corpus is modified in a minimal fashion to assimilate exactly the new information. In this form of belief change, when the reasoner revises by new information p ∨ q their belief corpus is modified so that p∨q is believed but stronger propositions like p∧q are not, no matter what beliefs are in the reasoner's initial corpus. We term this conservative belief change since the revised belief corpus is a conservative extension of the original belief corpus given the new information.     

Conditional Probability and Defeasible Inference

We offer a probabilistic model of rational consequence relations (Lehmann and Magidor, 1990) by appealing to the extension of the classical Ramsey–Adams test proposed by Vann McGee in (McGee, 1994). Previous and influential models of non-monotonic consequence relations have been produced in terms of the dynamics of expectations (Gärdenfors and Makinson, 1994; Gärdenfors, 1993).Expectation is a term of art in these models, which should not be confused with the notion of expected utility. The expectations of an agent are some form of belief weaker than absolute certainty. Our model offers a modified and extended version of an account of qualitative belief in terms of conditional probability, first presented in (van Fraassen, 1995). We use this model to relate probabilistic and qualitative models of non-monotonic relations in terms of expectations. In doing so we propose a probabilistic model of the notion of expectation. We provide characterization results both for logically finite languages and for logically infinite, but countable, languages. The latter case shows the relevance of the axiom of countable additivity for our probability functions. We show that a rational logic defined over a logically infinite language can only be fully characterized in terms of finitely additive conditional probability. The research of both authors was supported in part by a grant from NSF, and, for Parikh, also by support from the research foundation of CUNY.     

Scientific Discovery on Positive Data via Belief Revision

A model of inductive inquiry is defined within a first-order context. Intuitively, the model pictures inquiry as a game between Nature and a scientist. To begin the game, a nonlogical vocabulary is agreed upon by the two players along with a partition of a class of structures for that vocabulary. Next, Nature secretly chooses one structure (the real world) from some cell of the partition. She then presents the scientist with a sequence of atomic facts about the chosen structure. With each new datum the scientist announces a guess about the cell to which the chosen structure belongs. To succeed in his inquiry, the scientist's successive conjectures must be correct all but finitely often, that is, the conjectures must converge in the limit to the correct cell. A special kind of scientist selects his hypotheses on the basis of a belief revision operator. We show that reliance on belief revision allows scientists to solve a wide class of problems.     

Implementation of Belief Change Operators Using BDDs

While the theory of belief change has attracted a lot of interest from researchers, work on implementing belief change and actually putting it to use in real-world problems is still scarce. In this paper, we present an implementation of propositional belief change using Binary Decision Diagrams. Upper complexity bounds for the algorithm are presented and discussed. The approach is presented both in the general case, as well as on specific belief change operators from the literature. In an effort to gain a better understanding of the empirical efficiency of the algorithms involved, a fault diagnosis problem on combinational circuits is presented, implemented and evaluated.     

Children's Understanding of Behavioral Consequences of Epistemic States: A Comparison of Knowledge,Ignorance, and False Belief

The author addressed the issue of the simultaneity of false belief and knowledge understanding by investigating children's ability to predict the behavioral consequences of knowledge, ignorance, and false belief. The second aim of the study was to explore the role of counterfactuals in knowledge understanding. Ninety-nine (99) children, age 3–7 years old, completed the unexpected transfer task and a newly designed task in which a protagonist experienced 1 of the following 4 situations: knowing a fact, not knowing a fact, knowing a procedure, and not knowing a procedure. The results showed that factual ignorance was as difficult as false belief for the children, whereas the other conditions were all easier than false belief, suggesting that the well-known lag between ignorance and false belief may be partly methodologically based. The results provide support for a common underlying conceptual system for both knowing and believing, and evidence of the role of counterfactual reasoning in the development of epistemic state understanding. Methodological variations of the new task are proposed for future research.     

A Model for Structural Changes of Belief

The paper suggests a way of modeling belief changes within the tradition of formal belief revision theories. The present model extends the scope of traditional proposals, such as AGM, so as to take care of “structural belief changes” – a type of radical shifts that is best illustrated with, but not limited to, instances of scientific discovery; we obtain AGM expansions and contractions as limiting cases. The representation strategy relies on a non-standard use of a semantic machinery. More precisely, the model seeks to correlate knowledge states with interpretations of a given formal language L, in such a way that the epistemic state of an agent at a given time gives rise to a picture of how things could be, if there weren’t anything else to know. Interpretations of L proceed along supervaluational ideas; hence, the model as a whole can be seen as a particular application of supervaluational semantics to epistemic matters. Presented by Hannes Leitgeb     

A Grim Semantics For Logics of Belief

Patrick Grim has presented arguments supporting the intuition that any notion of a totality of truths is incoherent. We suggest a natural semantics for various logics of belief which reflect Grim’s intuition. The semantics is a topological semantics, and we suggest that the condition can be interpreted to reflect Grim’s intuition. Beyond this, we present a natural canonical topological model for K4 and KD4.     

Algebras of Intervals and a Logic of Conditional Assertions

Intervals in boolean algebras enter into the study of conditional assertions (or events) in two ways: directly, either from intuitive arguments or from Goodman, Nguyen and Walker's representation theorem, as suitable mathematical entities to bear conditional probabilities, or indirectly, via a representation theorem for the family of algebras associated with de Finetti's three-valued logic of conditional assertions/events. Further representation theorems forge a connection with rough sets. The representation theorems and an equivalent of the boolean prime ideal theorem yield an algebraic completeness theorem for the three-valued logic. This in turn leads to a Henkin-style completeness theorem. Adequacy with respect to a family of Kripke models for de Finetti's logic, ukasiewicz's three-valued logic and Priest's Logic of Paradox is demonstrated. The extension to first-order yields a short proof of adequacy for Körner's logic of inexact predicates.     

Woods on Ideals of Rationality in Dialogue

Woods' paper Ideals of Rationality in Dialogue raises six problems for dialogue theory. Woods is right about the seriousness of the problems, but one school of dialogue, that stemming from the work of Charles Hamblin, avoids each of Woods' problems by using commitment instead of belief and by using only immediate logical relations. This paper summarises the reasons Hamblin's school took this course, and explains how Woods' problems are thereby avoided.     

外表真实区别、表征变化和错误信念的任务分析

自20世纪80年代以来,“心理理论”已成为发展心理学的研究热点和最活跃、最多产的领域。为了分析和比较“心理理论”的实验任务,该研究以济南市3所幼儿园中的233名3—6岁儿童为有效被试。进行了“意外转移。和“欺骗外表”两种心理理论实验任务。得出如下主要结论：(1)意外转移任务中内隐错误信念显著难于标准错误信念,易化错误信念与标准错误信念的难度不存在显著差异。(2)欺骗外表任务中外表真实区别难度显著低于表征变化和错误信念。(3)意外转移任务的错误信念显著难于欺骗外表任务的错误信念。     

情绪状态对大学生条件推理的影响

采用不同情绪效价的电影片断诱发大学生不同的情绪,并运用眼动仪器记录条件推理的过程和结果,探讨了不同情绪状态对条件推理的影响状况。实验采用3（情绪组别：积极情绪、消极情绪、中性情绪）×4（推理形式：MP、DA、AC、MT）的混合实验设计。研究结果发现,中性情绪状态下的条件推理成绩显著地高于积极和消极情绪状态,结果支持抑制假说。     

大学生精神信仰的现状研究

本研究首次关注大学生的精神信仰,通过问卷对1100名大学生调查,发现大学生精神信仰存在如下特点：社会信仰占优势,其次依次为实用信仰和超自然信仰;民族主义、生命崇拜和国家主义位居前三位,宗教信仰、金钱崇拜和神灵崇拜位居后三位。     

条件推理中的二元效应初探

通过预备实验选取前件(或后件)是二元(或多元)的5种条件命题的4种推理形式作为实验材料,以大学本科生为被试,考察了五种不同条件命题类型对4种推理结果的影响.结果表明命题类型、推理规则以及两者的交互作用都非常显著.这个结果进一步验证了条件推理的集合映射模型.     

逻辑训练对不同理性思维方式大学生三段论推理的影响

采用理性—经验思维方式量表对105名大学生进行测量,选出高、低理性思维方式各35名大学生进行实验,探讨了逻辑训练对不同理性思维方式大学生三段论推理的影响。结果表明：(1)高理性思维方式个体三段论推理的平均反应时快于低理性思维方式个体;非冲突类型题目推理的平均正确率高于冲突类型题目;逻辑训练可以提高个体三段论推理的平均反应时和正确率;(2)逻辑训练后非冲突任务类型题目的平均正确率高于冲突任务类型题目;(3)逻辑训练对低理性思维方式个体冲突任务类型题目平均正确率的提高效果更明显。这意味着逻辑训练可以显著提升个体的推理成绩,但不能完全消除信念偏差对推理的影响,而且逻辑训练对低理性思维方式个体推理成绩的提升效果更加明显。     

一种应用于中医阴阳五行诊断学说的次协调逻辑(英文)

中医阴阳五行学说博大情深,是中医辨证论治的理论基础,也是指导中医临床诊断与治疗的基本原理,因此对于中医的理论与实践都有着十分重要的价值。但长期以来,一直缺乏对该学说进行严格的形式化研究,使之难以与不断发展中的中医现代化进程相适应。本文就是在这一学说核心内容的基础上,介绍引入次协调逻辑、缺省推理逻辑等先进逻辑来与中医诊断学结合的思想和方法,这样的目的是为今后构造一种符合中医诊断原则的中医阴阳五行推演逻辑系统作准备,该逻辑系统将用来描述基本的中医辨证推演过程。     

“蚁族”群体的公正世界信念与幸福感研究

以居住在北京小月河地区的304名“蚁族”为被试,采用公正世界信念问卷、积极消极情感问卷和生活满意度问卷,考察了一般公正世界信念、个人公正世界信念以及幸福感之间的关系,结果表明:(1)“蚁族”的生活满意度偏低,但其情绪状态仍然乐观,积极情感体验较高,且具有较高水平的公正世界信念;(2)公正世界信念对幸福感有显著的正向预测作用,公正世界信念水平越高的“蚁族”越幸福;(3)个人公正世界信念在一般公正世界信念和幸福感间起中介作用,即越相信世界是公正的“蚁族”更倾向于相信自己已经或即将受到的对待是公正的,最终提升幸福感。     

"状态改变:状态继续"与"做:不做"

检查了“做／不做”这对概念的不足后．本文用“状态改变／状态继续”来替代“做／不做”。在“状态改变-状态继续”框架基础上将事件分为“整体事件”和“分段事件”。研究证实“做／不做”只适合于“整体事件”而不适合“分段事件”。最后．该框架部分也解释了长期存在于实验研究与现场研究中的假设思想所表现出的差异。     

概念改变的本体类别研究

概念改变是科学学习和教学的重要问题。研究表明有些错误概念难于转变,本文从本体类别的观点出发,阐释了错误概念难于改变的原因,进而细致地分析了力的概念,以支持本体类别的观点,最后提出跨本体类别间概念改变的教学对策。