非形式论证的评价方法

一非形式论证 (informalargument)是与形式论证相区别的逻辑论证。形式论证是形式逻辑研究的内容 ,非形式论证是非形式逻辑 (informallogic)的研究内容。非形式逻辑于 2 0世纪70年代在美国兴起 ,用“非形式”命名这种逻辑 ,意指这是一种不严格的逻辑。形式论证具有固定的结构 ,要求结论从前提演绎得出 ,否则论证无效。非形式论证的结构常常不明显 ,它不单纯要求结论从前提必然得出 ,也允许结论得到前提足够的支持 ,仅当前提对结论的支持不足够时 ,才认为论证是谬误。对于论证 ,形式逻辑关注它的演绎有效性问题 ,非形式逻辑关注它的有效性程…     

第二讲 论证的评估——比尔兹利图

随着对“实践的逻辑”要求的不断增长和数理逻辑对日常思维中逻辑问题的无能为力的日益显著,非形式逻辑越来越引起逻辑学家、语言学家的关注。非形式逻辑以论证为中心,力图回答与此相关的一系列问题,如论证的分析,语言预设的特征以及谬误的类型等。其中对论证的分析占有特别重要的地位。蒙诺·比尔兹利(Monroe Beardsley)采用图表的形式来分析论证的结构以帮助人们对论证进行评估,这种图表经过斯蒂·文·托马斯(S·N·Thomas)和诺尔特(J.E. Nolt)的发展和完善,就形成了所谓的     

论证的形式模型概述及其在哲学上的应用

论证是一个用理由支持观点以及回应其所受攻击的过程。在过去的几十年里,论证已经成为哲学和人工智能研究领域中的一个重要主题。在哲学方面,十九世纪50年代和60年代图尔敏和佩雷尔曼对形式逻辑的批判,促进了非形式逻辑这一学科的产生,它研究推理和论证的非形式模型。在人工智能方面,论证的形式模型也发展成为常识推理和多主体冲突解决的基本模型。本文将讨论后一领域中所研究发展的形式模型如何能够用以澄清一些哲学领域、以及非形式逻辑领域中的理论问题和争议。本文的一个重要观点是,图尔敏和佩雷尔曼时代的形式逻辑只关注数学化的推理,但那些非数学化的推理形式其实同样也能够被形式化。     

权衡论证的结构与图解

权衡论证是一种同时包含正面的、支持结论的理由与反面的、反对结论的理由的论证,其结论的证成源于正面理由的逻辑力量经过权衡胜过了反面理由。自韦尔曼在1971年首次明确提出存在这种独特的论证以来,非形式逻辑学家希契柯克、戈维尔、汉森、弗里曼等先后针对权衡论证的结构与图解提出了各自的观点和方法,但彼此围绕如何看待反面理由在论证中的地位,如何把握正、反两面理由与结论的联系方式,如何图解权衡论证的结构等问题,意见分歧严重。通过揭示上述学者在这些问题上的所见所蔽,本文认为反面理由可以被视作论证的一个非基本的构成要素,主张权衡论证具有收敛与组合混合而成的双层结构,引进了一种图解这种论证的新方法。     

论证型式的规范性

论证型式刻画了既非演绎也非归纳的所谓第三类论证即假定性论证的推论结构。以非形式逻辑学家沃尔顿、布莱尔、汉森为代表的肯定派主张型式具有规范性,平托则对这一主流看法表示反对。通过对肯定派与否定派相关论述的批判性考察,本文厘清了“论证型式的规范性”论题的内涵,提出型式的规范性包含证明力与约束力双重维度;其次,讨论了批判性问题在评估假定性论证时的显性运用和隐性运用,揭示了肯定派论述中的不一致与概念混淆,在平托的基础上进一步论证了型式没有证明力,没有推论性联系上的好坏之分,假定性论证不能仅凭所例示的型式而区分出好坏;最后,考察了型式与论证提出者、接受者在对话中的行为之间的关系,修正了肯定派的某些提法,认为型式能够引导论证参与者根据对话类型的目标与规则进行话步交换并对实际对话进行评估,但这种约束是间接的、有限度的。     

非形式逻辑与演绎主义

非形式逻辑出现于上个世纪70年代,它首先是一种寻求更好的大学逻辑教学方式的努力。进而,非形式逻辑学者们逐渐开始触及和探讨越来越多的理论议题,即发展不依赖于形式逻辑的关于论证以及好论证的理解方式。在1998年世界哲学大会上,布莱尔和我阐释了非形式逻辑为哲学所带来的理论后果,其中一点我们称之为“演绎主义的终结”。那时我们并未给出演绎主义的定义,而只是把它等同于麦金泰尔的那个精炼的说法：“任何推理,不是演绎的,就是有缺陷的。”但现在看来,我们在当时就作出“演绎主义的终结”这一论断,显然是有点为时过早了。因为演绎主义似乎至今都还很有生命力,甚至在那些倾向于非形式逻辑的学者那里它也能得到支持：恩尼斯长期以来都辩护演绎主义是一种论证重构策略,格罗尔克更是致力于辩护它是一种论证评价理论。在本文中我将论证,非形式逻辑最好被理解为一种不诉诸于演绎技巧和演绎规范的逻辑研究。当我们意识到演绎和演绎主义已经如何深深地扎根于我们的哲学发展史中,并且牢牢地控制了我们关于逻辑研究的理解,我们就能明白非形式逻辑这一理论努力是多么的困难和重要。我将首先澄清“演绎主义”的意思,然后再分别考察那些赞成和反对演绎主义的论证,最后,我将表明非形式逻辑是从演绎主义中挽救逻辑的理论尝试。     

权衡论证：一种语用论辩学的分析CSSCI

由于权衡论证中同时引用了正反两方面的理由来证明一个观点,它被视为一种特殊的论证类型,并得到学界的持续关注和探讨。非形式逻辑学者认为,权衡论证对应着一个“将正反两方面理由加以权衡后得出结论”的特殊机制,因而需要通过增加“平衡考虑前提”来对其进行逻辑重构。这一做法强调反面理由的逻辑功能,但却带来一系列的理论问题。借助语用论辩学的理论工具,可以将权衡论证解析为一种策略操控的特定模式,这一分析不仅能很好地揭示权衡论证的特点和机制,而且还展现出理论上的简洁性和优越性。权衡论证中引述反面理由的目的,并不是为结论的证成提供逻辑依据,而是为增加说服效果而采取的修辞策略。进而,要刻画权衡论证的基本特性,其关键在于阐明其中所运用的特殊语言表达技巧,以及它如何增进了论证对于听众的说服效果。     

广义论证视域下的中国逻辑史开放研究——以《战国策》为例

本文以广义论证作为视角,以《战国策》典籍作为文本,对《战国策》一书中体现出来的论证逻辑思想进行分析,并对如何评估《战国策》所体现出来的论证提出粗浅的看法:《战国策》一书所体现出来的广义论证思想是中国古代逻辑理论和思想的典范;《战国策》具有自身独特的论证方法和架构;对《战国策》体现出来的论证评估不能简单使用西方的非形式逻辑的评估方法,应该立足中国传统文化,提出新的评估方式或方法。     

论证有几种类型？

对于论证中理由的充分性,可以从两个维度来加以分析,一个是从逻辑上,一个是从认识论上。基于此,本文提出了一种新的论证类型理论。从逻辑上而言,论证中从前提推至结论的过程,它可能是确凿无疑的,也可能仅仅是可废止的。从认识论上来看,能够保证论证成立的依据,其正当性可能被先验地证成,也可能是被后验地证成。因此,论证可以区分为如下四种类型：先验并确凿无疑、先验且可废止、后验且可废止、以及表面上看似的后验并确凿无疑。此外,也有一些论证,其成立依据可能同时涉及到先验和后验的证成。本文给出了以上各种论证类型的具体例示,并将这一新的分类方法与其它论证类型理论进行了比较。     

作为程序与属性的论辩术——析当代论证理论中“论辩术”视角的差异解读

当代论证理论中"论辩术"之理论视角存在着两种不同的解读方式。一种以语用论辩术理论为代表,将"论辩术"外化为论证活动的程序与规则,另一种以非形式逻辑理论为代表,将"论辩术"内化为论证成果的属性或品质。对这两种"论辩术"的解析将揭示出语用论辩术与非形式逻辑在规范性理论之建构与情境性实践之关注间的深层差异,同时也展现出其自身在谬误研究及论证界定等当代论证研究议题上的理论潜力。     

Johnson and the Soundness Doctrine

Why informal logic? Informal logic is a group of proposals meant to contrast with, replace, and reject formal logic, at least for the analysis and evaluation of everyday arguments. Why reject formal logic? Formal logic is criticized and claimed to be inadequate because of its commitment to the soundness doctrine. In this paper I will examine and try to respond to some of these criticisms. It is not my aim to examine every argument ever given against formal logic; I am limiting myself to those that, as a matter of historical fact, were instrumental in the replacement of formal logic by informal logic and initially established informal logic as a separate discipline (in particular, Toulmin’s attacks on what he calls the “analytic ideal” will not form part of the discussion and were not instrumental in this way, only becoming appreciated later). If the criticism of the soundness doctrine is defective, then the move from formal logic to informal logic was not theoretically well-motivated. It is this motivation that I wish to bring into question, rather than the adequacy or inadequacy of formal or informal logic as such. While I will tend to the view that formal logic is as adequate as it is reasonable to expect, the real issue is whether it is inadequate for the reasons that, as a matter of historical fact, were used to motivate its rejection.     

How to think about informal proofs

It is argued in this study that (i) progress in the philosophy of mathematical practice requires a general positive account of informal proof; (ii) the best candidate is to think of informal proofs as arguments that depend on their matter as well as their logical form; (iii) articulating the dependency of informal inferences on their content requires a redefinition of logic as the general study of inferential actions; (iv) it is a decisive advantage of this conception of logic that it accommodates the many mathematical proofs that include actions on objects other than propositions; (v) this conception of logic permits the articulation of project-sized tasks for the philosophy of mathematical practice, thereby supplying a partial characterisation of normal research in the field.     

Structure and pragmatics in informal argument: circularity and question-begging

Most everyday arguments are informal, as contrasted with the formal arguments of logic and mathematics. Whereas formal argument is well understood, the nature of informal argument is more elusive. A recent study by Rips (2002) provides further evidence regarding the roles of structure and pragmatics in informal argument.     

Historical Origins of Argumentum ad Consequentiam

What are the historical origins of the argumentum ad consequentiam, the argument from (or literally, to) consequences, sometimes featured as an informal fallacy in logic textbooks? As shown in this paper, knowledge of the argument can be traced back to Aristotle (who did not treat it as a fallacy, but as a reasonable argument). And this type of argument shows a spotty history of recognition in logic texts and manuals over the centuries. But how it got into the modern logic textbooks as a fallacy remains somewhat obscure. Its modern genesis is traced to the logic text of James McCosh (1879).     

Adequate formalization

This article identifies problems with regard to providing criteria that regulate the matching of logical formulae and natural language. We then take on to solve these problems by defining a necessary and sufficient criterion of adequate formalization. On the basis of this criterion we argue that logic should not be seen as an ars iudicandi capable of evaluating the validity or invalidity of informal arguments, but as an ars explicandi that renders transparent the formal structure of informal reasoning.     

Reasoned use of expertise in argumentation

This article evaluates the strengths and weaknesses of arguments based on appeals to expertise. The intersection of two areas is explored: (i) the traditional argumentum ad verecundiam (literally, appeal to modesty, but characteristically the appeal to the authority of expert judgment) in informal logic, and (ii) the uses of expert systems in artificial intelligence. The article identifies a model of practical reasoning that underlies the logic of expert systems and the model of argument appropriate for the informal logic of the argumentum ad verecundiam.     

Exhibiting interpretational and representational validity

A natural language argument may be valid in at least two nonequivalent senses: it may be interpretationally or representationally valid (Etchemendy in The concept of logical consequence. Harvard University Press, Cambridge, 1990). Interpretational and representational validity can both be formally exhibited by classical first-order logic. However, as these two notions of informal validity differ extensionally and first-order logic fixes one determinate extension for the notion of formal validity (or consequence), some arguments must be formalized by unrelated nonequivalent formalizations in order to formally account for their interpretational or representational validity, respectively. As a consequence, arguments must be formalized subject to different criteria of adequate formalization depending on which variant of informal validity is to be revealed. This paper develops different criteria that formalizations of an argument have to satisfy in order to exhibit the latter’s interpretational or representational validity.