Against logical generalism

The orthodox view of logic takes for granted the central importance of logical principles. Logic, and thus logical reasoning, is to be understood as a system of rules or principles with universal application. Let us call this orthodox view logical generalism. In this paper we argue that logical generalism, whether monist or pluralist, is wrong. We then outline an account of logical consequence in the absence of general logical principles, which we call logical particularism.

     

Differentiation and infinitesimal relatives in peirce’s 1870 paper on logic: A new interpretation

The process of ‘logical differentiation’ was introduced by Peirce in 1870. Directly analogous to mathematical differentiation, it uses logical terms instead of mathematical variables. Here, this mysterious process receives new interpretations which serve to clarify Peirce’s use of logical terms. I introduce the logical terms, the operation of multiplication, the logical analogy to the binomial theorem, infinitesimal relatives, the concepts of numerical coefficients and the number associated with each term. I also analyse the algebraic development of ‘logical differentiation’ and consider in depth one application of the process     

Long-term recognition memory for sentences

The present studies examined immediate and one-week delayed recognition performance for active and passive sentences. Recognition tests included distractor sentences wherein the logical subject, verb, of logical object of a sentence was replaced by a semantically confusable, visually confusable, or unrelated distractor. Results indicated that logical subjects, verbs, and logical objects of sentences were recognized equally well during immediate testing. During delayed testing, changes in the logical object or recipient of the action were not detected as well as verb changes of logical subject changes. The implications of these results for current sentence memory models were discussed.     

范畴三段论推理中信念偏差效应的实验研究

本研究利用三段论评价任务,分析了已有信念与三段论逻辑状态间的交互影响,探讨了三段论推理判断中信念偏差的存在与作用机制,同时从信念偏差角度对心理模型理论进行了初步验证。结果发现：1．范畴三段论推理的逻辑判断过程中存在信念偏差效应;2．信念偏差效应以逻辑状态与结论可信性交互作用的方式存在;3当逻辑结果与信念相一致时,信念会促进逻辑反应,反之则妨碍逻辑反应;4．信念偏差效应对逻辑有效、结论不可信的单模型三段论问题影响最大,而对逻辑有效、结论不可信的多模型三段论问题相对影响最小。     

Limiting logical pluralism

In this paper I argue that pluralism at the level of logical systems requires a certain monism at the meta-logical level, and so, in a sense, there cannot be pluralism all the way down. The adequate alternative logical systems bottom out in a shared basic meta-logic, and as such, logical pluralism is limited. I argue that the content of this basic meta-logic must include the analogue of logical rules Modus Ponens (MP) and Universal Instantiation (UI). I show this through a detailed analysis of the ‘adoption problem’, which manifests something special about MP and UI. It appears that MP and UI underwrite the very nature of a logical rule of inference, due to all rules of inference being conditional and universal in their structure. As such, all logical rules presuppose MP and UI, making MP and UI self-governing, basic, unadoptable, and (most relevantly to logical pluralism) required in the meta-logic for the adequacy of any logical system.

     

Why logical pluralism?

This paper scrutinizes the debate over logical pluralism. I hope to make this debate more tractable by addressing the question of motivating data: what would count as strong evidence in favor of logical pluralism? Any research program should be able to answer this question, but when faced with this task, many logical pluralists fall back on brute intuitions. This sets logical pluralism on a weak foundation and makes it seem as if nothing pressing is at stake in the debate. The present paper aims to improve this situation by looking at a promising case study and drawing general lessons about the kind of evidence that would support logical pluralism. I argue that the best motivation for logical pluralism will ultimately be rooted in certain kinds of performative data.

     

Coordinating mathematical concepts with the demands of authority: children’s reasoning about conventional and second-order logical rules

Arithmetic algorithms include two types of rules: conventional rules that may be changed by authority, and may legitimately vary from one classroom or country to another (e.g. putting the sum below, rather than above, the numbers added) and logical rules that involve the logic of the algorithm. Changes in the logical rules produce incorrect answers. Hence these rules are not legitimately alterable by authority. Second-order logical rules depend on the particular conventions of the symbol system used (e.g. the rule for carrying in place-value addition). Given the symbol system used, these rules are not legitimately alterable by authority. However, as a result of their dependence on the symbol system, children may have difficulty distinguishing second-order logical rules from conventional rules. Ninety-eight children in grades 2 through 5 were interviewed about the correctness of answers obtained using alternatives to standard conventional and second-order logical rules, and about the legitimacy of authorities to change the rules. Half the children across this age range treated second-order logical rules as somewhat like conventions, judging that an answer resulting from an alternative to a second-order logical rule is correct if sanctioned by authority. With increasing age children increasingly limited the jurisdiction of authority over second-order logical rules.     

Can First-Order Logical Truth be Defined in Purely Extensional Terms?

W. V. Quine thinks logical truth can be defined in purely extensional terms, as follows: a logical truth is a true sentence that exemplifies a logical form all of whose instances are true. P. F. Strawson objects that one cannot say what it is for a particular use of a sentence to exemplify a logical form without appealing to intensional notions, and hence that Quine's efforts to define logical truth in purely extensional terms cannot succeed. Quine's reply to this criticism is confused in ways that have not yet been noticed in the literature. This may seem to favour Strawson's side of the debate. In fact, however, a proper analysis of the difficulties that Quine's reply faces suggests a new way to clarify and defend the view that logical truth can be defined in purely extensional terms.     

Reinflating Logical Consequence

Shapiro (Philos Q 61:320–342, 2011) argues that, if we are deflationists about truth, we should be deflationists about logical consequence. Like the truth predicate, he claims, the logical consequence predicate is merely a device of generalisation and more substantial characterisation, e.g. proof- or model-theoretic, is mistaken. I reject his analogy between truth and logical consequence and argue that, by appreciating how the logical consequence predicate is used as well as the goals of proof theory and model theory, we can be deflationists about truth but not logical consequence.     

Problems for Logical Pluralism

I argue that Beall and Restall's logical pluralism fails. Beall–Restall pluralism is the claim that there are different, equally correct logical consequence relations in a single language. Their position fails for two, related, reasons: first, it relies on an unmotivated conception of the ‘settled core’ of consequence: they believe that truth-preservation, necessity, formality and normativity are ‘settled’ features of logical consequence and that any relation satisfying these criteria is a logical consequence relation. I consider historical evidence and argue that their position relies on an unmotivated conception of the settled features of logical consequence. There are many features that are just as settled but which are inconsistent with pluralism. Second, I argue that Beall–Restall pluralism fails to hold in a single language with a single selection of logical constants, which they require for the position to be distinct from Carnap's. I consider various ways in which Beall and Restall can resist this meaning variance, particularly for negation, but argue that the strongest way relies on an unmotivated conception of the settled features of the logical constants.     

平等的正义性及其形式原则考论

正义在逻辑上是比平等更底层、更基础的概念,可以为平等理论提供逻辑基础,平等的论证是一种正义性论证。支撑平等的正义的形式原则相同的人相同对待,不同的人不同对待,恰恰是从平等的描述性概念即人们的相同性到平等的规范性概念即平等要求的逻辑过渡。     

Following logical realism where it leads

Philosophical Studies - Logical realism is the view that there is logical structure in the world. I argue that, if logical realism is true, then we are deeply ignorant of that logical structure:...     

逻辑图表的发展

长期以来,逻辑图表被逻辑学家们仅仅视为教学辅助工具;但逻辑图表从Euler图到Venn图再到存在图表和概念图表的发展表明,它已经超越出教学工具这一狭隘界限,从而获得了更为深刻,广泛的意义,实际上逻辑图表是与我们标准数理逻辑记法相区别的另一种有效的逻辑记法,而且有着更强的直观性和可应用性。     

Reasoning and Representing

I argue that logical understanding is not propositional knowledgebut is rather a species of practical knowledge. I further arguethat given the best explanation of logical understanding someversion or another of inferential role semantics must be the correct account of the determinants of logical content.     

Logical Truth and Tarskian Logical Truth

This paper examines the question of the extensional correctness of Tarskian definitions of logical truth and logical consequence. I identify a few different informal properties which are necessary for a sentence to be an informal logical truth and look at whether they are necessary properties of Tarskian logical truths. I examine arguments by John Etchemendy and Vann McGee to the effect that some of those properties are not necessary properties of some Tarskian logical truths, and find them unconvincing. I stress the point that since the hypothesis that Tarski's definitions are extensionally correct is deeply entrenched, the burden of proof is still on the shoulders of Tarski's critics, who have not lifted the burden. This revised version was published online in June 2006 with corrections to the Cover Date.     

Evidence that logical reasoning depends on conscious processing

Humans, unlike other animals, are equipped with a powerful brain that permits conscious awareness and reflection. A growing trend in psychological science has questioned the benefits of consciousness, however. Testing a hypothesis advanced by [Lieberman, M. D., Gaunt, R., Gilbert, D. T., & Trope, Y. (2002). Reflection and reflexion: A social cognitive neuroscience approach to attributional inference. Advances in Experimental Social Psychology, 34, 199-249], four studies suggested that the conscious, reflective processing system is vital for logical reasoning. Substantial decrements in logical reasoning were found when a cognitive load manipulation preoccupied conscious processing, while hampering the nonconscious system with consciously suppressed thoughts failed to impair reasoning (Experiment 1). Nonconscious activation (priming) of the idea of logical reasoning increased the activation of logic-relevant concepts, but failed to improve logical reasoning performance (Experiments 2a-2c) unless the logical conclusions were largely intuitive and thus not reliant on logical reasoning (Experiment 3). Meanwhile, stimulating the conscious goal of reasoning well led to improvements in reasoning performance (Experiment 4). These findings offer evidence that logical reasoning is aided by the conscious, reflective processing system.     

Logical knowledge and ordinary reasoning

This paper argues that the prominent accounts of logical knowledge have the consequence that they conflict with ordinary reasoning. On these accounts knowing a logical principle, for instance, is having a disposition to infer according to it. These accounts in particular conflict with so-called ‘reasoned change in view’, where someone does not infer according to a logical principle but revise their views instead. The paper also outlines a propositional account of logical knowledge which does not conflict with ordinary reasoning.     

Combinatorial Bitstring Semantics for Arbitrary Logical Fragments

Logical geometry systematically studies Aristotelian diagrams, such as the classical square of oppositions and its extensions. These investigations rely heavily on the use of bitstrings, which are compact combinatorial representations of formulas that allow us to quickly determine their Aristotelian relations. However, because of their general nature, bitstrings can be applied to a wide variety of topics in philosophical logic beyond those of logical geometry. Hence, the main aim of this paper is to present a systematic technique for assigning bitstrings to arbitrary finite fragments of formulas in arbitrary logical systems, and to study the logical and combinatorial properties of this technique. It is based on the partition of logical space that is induced by a given fragment, and sheds new light on a number of interesting issues, such as the logic-dependence of the Aristotelian relations and the subtle interplay between the Aristotelian and Boolean structure of logical fragments. Finally, the bitstring technique also allows us to systematically analyze fragments from contemporary logical systems, such as public announcement logic, which could not be done before.