Traditional Logic,Modern Logic and Natural Language

In a recent paper Johan van Benthem reviews earlier work done by himself and colleagues on ‘natural logic’. His paper makes a number of challenging comments on the relationships between traditional logic, modern logic and natural logic. I respond to his challenge, by drawing what I think are the most significant lines dividing traditional logic from modern. The leading difference is in the way logic is expected to be used for checking arguments. For traditionals the checking is local, i.e. separately for each inference step. Between inference steps, several kinds of paraphrasing are allowed. Today we formalise globally: we choose a symbolisation that works for the entire argument, and thus we eliminate intuitive steps and changes of viewpoint during the argument. Frege and Peano recast the logical rules so as to make this possible. I comment also on the traditional assumption that logical processing takes place at the top syntactic level, and I question Johan’s view that natural logic is ‘natural’.     

Later Medieval Metaphysics. Ontology,Language & Logic

WALTER BURLEIGH, Von der Reinheit der Kunst der Logik. Erster Traktat: Von den Eigenschaften der Termini. Übersetzt und mit Einfuhrung und Anmerkungen herausgegeben von Peter Kunze. Lateinisch-deutsch. (Philosophische Bibliothek, Nr. 401 .) Hamburg: Felix Meiner, 1988. xlvii + 269 pp. 64 DM.     

F. M. Kamm,Morality, Mortality. Volume II: Rights,Duties, and Status

Theoretical Medicine and Bioethics -     

Logic,Logic, and Logic

In his recent paper in History and Philosophy of Logic, John Kearns argues for a solution of the Liar paradox using an illocutionary logic (Kearns 2007 Kearns, J. 2007. ‘An illocutionary logical explanation of the Liar Paradox’. History and Philosophy of Logic, 28: 31–66. [Taylor &; Francis Online], [Web of Science ®] , [Google Scholar]). Paraconsistent approaches, especially dialetheism, which accepts the Liar as being both true and false, are rejected by Kearns as making no ‘clear sense’ (p. 51). In this critical note, I want to highlight some shortcomings of Kearns' approach that concern a general difficulty for supposed solutions to (semantic) antinomies like the Liar. It is not controversial that there are languages which avoid the Liar. For example, the language which consists of the single sentence ‘Benedict XVI was born in Germany’ lacks the resources to talk about semantics at all and thus avoids the Liar. Similarly, more interesting languages such as the propositional calculus avoid the Liar by lacking the power to express semantic concepts or to quantify over propositions. Kearns also agrees with the dialetheist claim that natural languages are semantically closed (i.e. are able to talk about their sentences and the semantic concepts and distinctions they employ). Without semantic closure, the Liar would be no real problem for us (speakers of natural languages). But given the claim, the expressive power of natural languages may lead to the semantic antinomies. The dialetheist argues for his position by proposing a general hypothesis (cf. Bremer 2005 Bremer, M. 2005. An Introduction to Paraconsistent Logics, Bern: Lang.  [Google Scholar], pp. 27–28): ‘(Dilemma) A linguistic framework that solves some antinomies and is able to express its linguistic resources is confronted with strengthened versions of the antinomies’. Thus, the dialetheist claims that either some semantic concepts used in a supposed solution to a semantic antinomy are inexpressible in the framework used (and so, in view of the claim, violate the aim of being a model of natural language), or else old antinomies are exchanged for new ones. One horn of the dilemma is having inexpressible semantic properties. The other is having strengthened versions of the antinomies, once all semantic properties used are expressible. This dilemma applies, I claim, to Kearns' approach as well.     

亚里士多德和墨家的逻辑和语言概念

亚里士多德逻辑和墨家逻辑是基于非常不同的本体论思想的。这可以从比较亚里士多德的＂类＂（genus）概念和墨家的＂类＂概念得到解释。传统的翻译把中文词＂同＂和＂异＂分别解释为＂相似＂和＂不同＂,以掩饰这两个概念的不同。据此,亚里士多德逻辑的理论意图是完全不同于具有实际意图的、作为论证指导的墨家逻辑。     

Minds as Connoting Systems: Logic and the Language of Thought

The principal aim of this essay is to discuss some logical features of the so-called Classical model of cognitive architecture as it is advocated by J. Fodor and Z. Pylyshyn in their much discussed article 'Connectionism and Cognitive Architecture: A Critical Analysis'. It is pointed out that their structural assumptions have consequences of a logical kind which call into question the view that the Classical architecture (in their sense) can be employed to model human cognition. It seems that the consequences have escaped Fodor and Pylyshyn's notice, or else they have failed to appreciate them, since some of their claims evidently conflict with them. It is also investigated whether the human mind can be characterized as being logical in some weaker sense of logic. Furthermore, it is argued that J. H. Fetzer's view that it is a semiotic system is more realistic than the Classical model, but the distinction he suggests between human cognition and other kinds may be problematic.     

逻辑、语言和哲学讲习班与研讨会综述

2011年6月13-18日,清华大学人文学院哲学系举办了逻辑、语言和哲学讲习班与研讨会。本次活动的主旨是：对逻辑学、自然语言和哲学的交叉研究领域中的一些课题进行深入的介绍,交流最新的研究成果,展示逻辑学在跨学科研究领域中的重要作用。本次活动分为两个部分：为期五天的讲习班与为期一天的研讨会。活动的参加者有：阿姆斯特丹大学与斯坦福大学的范丙申（Johan vanBenthem）教授,阿姆斯特丹大学的斯托科霍夫（Martin Stokhof）教授,哥德堡大学与斯德哥尔摩大学的威斯特斯达（Dag Westerstahl）教授,     

Beyond Language: Using Logic to Introduce New Philosophical Distinctions

Philosophy has to be communicable in language, and therefore, whatever it has to say must be expressible in (some) language. But in order to make progress, philosophy has to gradually extend and improve its terminological apparatus. It is argued that logical formalization is a highly useful tool for discovering and confirming distinctions that are not present in ordinary language or in pre-existing philosophical terminology. In particular, it is proposed that if two usages of a word require different logical formalizations, then that is a strong reason to distinguish between them also in informal philosophy. The distinction between two types of normative conditionals, conditional veritable norms and conditional normative rules, is used as an example to corroborate this proposal.