意外考试悖论的普莱尔刻画

20世纪著名哲学家、逻辑学家A.N.普莱尔(A. N. Prior)在其遗作中对意外考试悖论给出了一种新的形式刻画。这种刻画同卡普兰与蒙塔古的经典刻画之间的差异在于,后者依赖于一个复杂的自指句,而前者依赖于若干个非自指简单句的合取,并明显诉诸时间因素。因此,卡普兰与蒙塔古的推导必须在可表达自指的形式算术中进行,而普莱尔的推导则只需一阶逻辑框架。普莱尔刻画的独特价值在于,一是表明了意外考试悖论可以建构为非自指悖论,二是表明该悖论与知道者悖论虽有紧密联系,但具有本质差异,需要进行独立研究。     

关于说谎者悖论句变元理论的几点评论

说谎者悖论是最古老也最难以应付的悖论之一。本文以塔尔斯基的语言分层理论和克里普克的真值间隙理论为背景和参照点来比较文兰教授所提出的句变元理论解悖方案。文章主要从应对不同类型的说谎者悖论以及其他类似的非语义悖论（尤其是模态说谎者和认知说谎者）的角度出发,总结了句变元理论的两个独特之处。第一它揭示出自指以及真谓词在说谎者悖论中显明但不显著的作用;第二它可以应付大量结构相似的悖论并给出统一的解决方案。文章最后比较了克里普克的有根性概念和文兰的方程有解概念的异同,并提出了一些可以继续探索的相关问题。     

一种新型的语用悖论——合理行动悖论

合理行动悖论来自决策论和博弈论中关于行动的矛盾推理,诸如纽科姆难题、囚徒困境等,它们分别散落在博弈论及相关社会科学中。这些难题似乎属于独立领域,互不相关,并且各自都有针对性的解决方案。然而,我们的研究表明,它们实际上是一个庞大的语用悖论群落,具有共同结构和统一机理。     

中国近三十年逻辑悖论研究的主要特点与趋势

当代逻辑悖论研究有三个不同层面:一是特定领域某个或某组悖论的建构及其具体解悖方案研究;二是各种悖论及解悖方案的哲学研究;三是关于悖论的发现、解决及其功能的一般方法论研究。文革前,中国学界的逻辑悖论研究主要体现在莫绍揆、沈有鼎等学者在第一层面的研究上。中国学界关于逻     

试论语义悖论的弗完全理论

弗完全理论通过限制排中律的使用,弱化经典逻辑,采用非经典的三值语言来处理语义悖论,最终使得形式语言能够一致地包含自身的真谓词。文中我们讨论了弗完全理论的两种基本形式——基础的弗完全理论和高级的弗完全理论。基础的弗完全理论引入了＂真值空缺＂的思想,认为句子除了真假之外还有＂既不真也不假＂的第三值,像说谎者这样的语义悖论语句就落在真假之空缺中,该理论借助于对不动点的归纳构造过程证明了形式语言中真谓词的存在性。高级弗完全理论在前者的基础上引入一个适当的条件句,定义了一个＂更强的真＂,发展出了既满足真的素朴模式又具有不动点解释的、一致的高级弗完全理论。     

论归纳悖论研究的认知转向

归纳悖论研究是当代逻辑哲学、科学哲学、形式知识论等领域的核心话题之一。归纳悖论的两次研究高潮取得了一系列成果,但也存在许多不足。通过回归归纳悖论的源发语境,分析和澄清其涵义及真实\"悖境\",梳理解悖的历史脉络,可以表明归纳悖论的研究应该且正在实现认知转向。同时,这种认知转向对构建合理的信念接受理论、解决葛梯尔问题等知识论疑难、构建新的动态认知逻辑分支,都有重要的启发意义和价值。     

道德悖论研究的价值与意义

以悖论的认知范式,伦理学界考辨既有道德规范的合理性,审思道德实践领域的认知困境,试图给出消解道德悖论的一般路径.道德悼论研究至少具有三重价值和意义:可以推动道德理论实现质变性创新;增添人们的道德智慧、化解道德实践悖境;转换道德认知方式、提升人们的道德悖论思维水平.     

把握道德悖论需要注意的学理性问题——兼谈道德悖论研究的视界和价值与意义

不久前兴起的道德悖论研究虽然逐渐引起学界的重视,但对道德悖论的概念即\"什么是道德悖论\"的问题依然存在疑义,这是因为没有注意从学理上认同道德悖论的界定阅限、明晰道德价值实现结果之悖论与道德价值标准选择之悖论的关系、划清道德悖论与逻辑悖论的界限,以及理解道德悖论之现象与道德悖论之直党(思想)的区别.把握理解这几个学理的问题,是把握道德悖论概念、规范道德悖论研究并展现其应有价值和意义的方法论前提.     

道德悖论研究述要与思考

\"道德悖论\"是人类道德生活中亟待揭示与研究的重大理论问题。近些年来,一些学者就道德悖论的界说、特征、形态及其生成情境与因由、道德悖论研究的意义,乃至其认知路向的拓展等问题进行了持续性的探究,发表了一批积极成果。道德悖论研究需要从廓清其概念外延边界、注重学科交叉成果的应用、密切结合道德建设的实际问题等方面加以拓展,进一步发挥其理论研究的应用价值。     

可知性悖论的条件句分析

在处理可知性悖论时,学者们似乎口径一致地将可知的理解为一个模态词可能加上知识(为讨论方便,在此省略认知主体与时间),并且以类似的方式处理模态词可能。不同于大部分的学者,M.法拉(M.Fara)使用能力的概念来理解可能,并发展自己的理论。本文延续法拉的想法,但不同于法拉,采取虚拟条件句来理解可知的,亦即p是可知的会被分析成若如此这般成立,p会被知道这样的条件句。在这样的分析下,我们可以更清楚实在论与反实在论之间的争论究竟在哪,并且理解为什么反实在论会受到可知性悖论的威胁。     

Epistemic Principles and Epistemic Circularity

Can we show that our senses are reliable sources of information about the world? To show this, we need to establish that most of our perceptual judgments have been true. But we cannot determine these inductive instances without relying upon sense perception. Thus, it seems, we cannot establish the reliability of sense perception by means of an argument without falling into epistemic circularity. In this paper, I argue that this consequence is not an epistemological disaster. For this purpose, I defend a normative claim that it is reasonable to accept the general reliability of our perceptual judgments, instead of a factual claim that our perceptual judgments are generally reliable. More specifically, I offer a normative practical argument which explains why it is reasonable to accept the general reliability of our perceptual judgments, even though we cannot establish the general reliability of our perceptual judgments by means of theoretical reasoning.     

Circularity in ethotic structures

The aim of this paper is to provide a model that allows the representation and analysis of circularity in ethotic structures, i.e. in communication structures related to the speaker’s character and in particular, his credibility. The paper studies three types of cycles: in self-referential sentences, embedded testimony and ethotic begging the question. It is shown that standard models allow the reconstruction of the circularities only if those circular utterances are interpreted as ethotic arguments. Their alternative, assertive interpretation requires enriching the existing models with a purely ethotic component related to the credibility of the performer of any (not necessarily argumentative) speech act.     

Truth,Meaning, and Circularity

It is often argued that the combination of deflationism about truth and the truth-conditional theory of meaning is impossible for reasons of circularity. I distinguish, and reject, two strains of circularity argument. Arguments of the first strain hold that the combination has a circular account of the order in which one comes to know the meaning of a sentence and comes to know its truth condition. I show that these arguments fail to identify any circularity. Arguments of the second strain hold that the combination has a circular explanation of the ideas or concepts of meaning and truth. I show that these arguments identify a genuine, but acceptable, circularity.     

Minimalism and Paradoxes

This paper argues against minimalism about truth. It does so by way of acomparison of the theory of truth with the theory of sets, and considerationof where paradoxes may arise in each. The paper proceeds by asking twoseemingly unrelated questions. First, what is the theory of truth about?Answering this question shows that minimalism bears important similaritiesto naive set theory. Second, why is there no strengthened version ofRussell's paradox, as there is a strengthened Liar paradox? Answering thisquestion shows that like naive set theory, minimalism is unable to makeadequate progress in resolving the paradoxes, and must be replaced by adrastically different sort of theory. Such a theory, it is shown, must befundamentally non-minimalist.     

Antonyms and Paradoxes

Adjectives can be gradable or non-gradable and this aspect of their meaning is responsible for their different distribution and also for their classification into two different classes of antonyms. Non-gradable antonyms are called contradictories: they are neither true nor false together and exclude any middle term; gradable antonyms are called contraries: they are not simultaneously true, but may be simultaneously false. While with contraries a negative disjunction (neque...neque) can define an intermediate level, with contradictories it simply means that either term of the disjunction is excluded. There are however some Latin examples, such as neque vivus neque mortuus (`neither alive nor dead'), where the negation of a contradictory pair is used to convey a third, intermediate value. This third possibility is precisely what gives place to a paradox. Such an intermediate level can be defined also by terms like semivivus, semianimis (`half-dead'). Following Ducrot's theory on argumentation, such terms represent an argumentative attenuation, not with respect to life, rather with respect to death. With contradictories, in fact, the use of semi-, like the use of negation, gives the assertion of the opposite term as a result.