复合命题理解能力的发展

采用命题-图形匹配实验法,探讨了儿童、少年和青年人三个阶段的5种类型复合命题理解能力的发展.结果表明:(1)随着年龄增长,复合命题理解能力迅速提高;(2)对复合命题理解的难易,决定于构建的心理模型的数目.理解能力的发展根据心理模型的类型呈现不同的步调,单模型命题的理解在小学阶段已经很好地获得发展,双模型命题则在初中阶段获得较好的发展,三模型命题发展较迟,直至成年仍需发展.     

Field's Paradox and Its Medieval Solution

Hartry Field's revised logic for the theory of truth in his new book, Saving Truth from Paradox, seeking to preserve Tarski's T-scheme, does not admit a full theory of negation. In response, Crispin Wright proposed that the negation of a proposition is the proposition saying that some proposition inconsistent with the first is true. For this to work, we have to show that this proposition is entailed by any proposition incompatible with the first, that is, that it is the weakest proposition incompatible with the proposition whose negation it should be. To show that his proposal gave a full intuitionist theory of negation, Wright appealed to two principles, about incompatibility and entailment, and using them Field formulated a paradox of validity (or more precisely, of inconsistency).

The medieval mathematician, theologian and logician, Thomas Bradwardine, writing in the fourteenth century, proposed a solution to the paradoxes of truth which does not require any revision of logic. The key principle behind Bradwardine's solution is a pluralist doctrine of meaning, or signification, that propositions can mean more than they explicitly say. In particular, he proposed that signification is closed under entailment. In light of this, Bradwardine revised the truth-rules, in particular, refining the T-scheme, so that a proposition is true only if everything that it signifies obtains. Thereby, he was able to show that any proposition which signifies that it itself is false, also signifies that it is true, and consequently is false and not true. I show that Bradwardine's solution is also able to deal with Field's paradox and others of a similar nature. Hence Field's logical revisions are unnecessary to save truth from paradox.     

DO I HAVE TO BE HERE NOW?

Kaplan claims that (1) ‘I am here now’, though analytic, is not a necessary truth. But this sentence is not a proposition, in a sense of proposition in which some, but not all, sentences are propositions. Since it is not a proposition, it is not true, and consequently not analytic. It is in fact a fragment of a proposition, the same fragment as ‘he was there then’ in (2) ‘CJFW said in Oxford on 23 September 1991 that he was there then’. Sentences containing indexicals in general owe their sense to the corresponding fragments of sentences containing ‘quasi-indexicals’(‘then’, for example, is the quasi-indexical to ‘now’ as indexical). Someone uttering (1) assertively will thereby make a proposition like (2) true. (2) entails (3) ‘CJFW said in Oxford on 23 September 1993 that CJFW was in Oxford on 23 September 1991′. So by uttering (1) in the appropriate circumstances I made it true that I had asserted the proposition (4) ‘CJFW was in Oxford on 23 September 1991′. What is analytic and necessarily true is the proposition ‘If (3) then (4)’.     

Sharing and Confronting Propositions in Collaborative Inquiry Learning

This study investigates how collaborative knowledge construction within an inquiry learning environment can be assisted with scaffolds that aim to support students' hypothesis generation process. Sixty-six students on a university preparatory track worked collaboratively on a kinematics task. The instructional goal was to develop students' understanding of one-dimensional kinematics. All students completed a proposition test in which they indicated their individual opinions about the truth-value of specific propositions. Subsequently, students were coupled into dyads and assigned to one of three conditions: (a) a shared proposition scratchpad (expression builder), (b) a shared proposition table, and (c) a control condition. Students in the scratchpad condition were given an expression builder consisting of dropdown menus with pre-defined variables and relations. Students in the shared proposition table condition could combine individual opinions about the truth-value of a proposition into one shared proposition table that highlighted differences in opinion. Students in the control condition received no extra support related to propositions. Learning outcomes were assessed using a variety of pre- and posttests. The findings indicate that students supported with the shared proposition table showed significant gains for qualitative knowledge about relations. The number of unique propositions students discussed during the learning session was a significant predictor of learning gains. A more detailed analysis of students' interaction protocols suggests that students differed in their task perceptions, their interaction patterns, and their use of prior knowledge.     

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.     

Showing,Analysis and the Truth-Functionality of Logical Necessity in Wittgenstein's Tractatus

This paper aims to explain how the Tractatus attempts to unifylogic by deriving the truth-functionality of logical necessityfrom the thesis that a proposition shows its sense. I first interpret the Tractarian notion of showing as the displaying ofwhat is intrinsic to an expression (or a symbol). Then I argue that, according to theTractatus, the thesis that a proposition shows its sense implies the determinacy of sense, the possibility of the complete elimination of non-primitive symbols, the analyticity thesis and the strong analyticity thesis. The picture theory emerges as what provides the only acceptable account of an elementary proposition, subject to the constraint that a proposition must show its sense. The picture theory and the analyticity thesis then entail the contingency thesis (that an elementary proposition is contingent) and the independence thesis (that elementary propositions are mutually logically independent) which, together with the strong analyticity thesis, imply that all logical propositions are tautologies.     

Communicating in contextual ignorance

Synthese - When A utters a declarative sentence in a context to B, typically A can mean a proposition by the sentence, the sentence in context literally expresses a proposition (i.e. has a...     

Reasoning from inconsistency to consistency

This article presents a theory of how individuals reason from inconsistency to consistency. The theory is based on 3 main principles. First, individuals try to construct a single mental model of a possibility that satisfies a current set of propositions, and if the task is impossible, they infer that the set is inconsistent. Second, when an inconsistency arises from an incontrovertible fact, they retract any singularly dubious proposition or any proposition that is inconsistent with the fact; otherwise, they retract whichever proposition mismatches the fact. A mismatch can arise from a proposition that has only mental models that conflict with the fact or fail to represent it. Third, individuals use their causal knowledge-in the form of models of possibilities-to create explanations of what led to the inconsistency. A computer program implements the theory, and experimental results support each of its principles.     

Coherence and Truth: A Cognitive Model of Propositional Truth Attribution

The truth value assigned to a proposition is treated by philosophers, logicians, and most psychologists as an abstract construct, a theoretical object outside the cognitive system. Breaking away from this consensus, we propose to carry out a psychological investigation to analyse the objective, verifiable properties of representations categorized as true by human individuals. We shall reject the conception whereby attributing a truth value to a proposition is the result of the activation of knowledge about the truth of that proposition. We shall also exclude the conception of truth as the result of the establishment of a correspondence with the world. We propose that truth be understood as the result of a decision about the values taken on by the conditions for fulfilment of the act of referencing in a mental model. Our cognitive model of propositional truth attribution is built on the assumption that the truth value of a proposition is determined by the ability of that proposition to fit into the theory of the field to which it refers. This attribution is viewed as a two-stage cognitive activity. During the first stage, the features defining the coherence of the proposition in the activated mental model determine its plausibility value. This defines a generally inconsistent set of truth candidates. The second stage involves selecting the subset containing all propositions which, in context, will be considered true. Two selection criteria are used: maximum consistency and connectivity. The preliminary experimental results proved to be compatible with the proposed model.     

`She' and `He': Politically Correct Pronouns

It is argued that the pronouns `she' and `he' are disguised complexdemonstratives of the form `that female/male'. Three theories ofcomplex demonstratives are examined and shown to be committed to theview that `s/he' turns out to be an empty term when used to refer toa hermaphrodite. A fourth theory of complex demonstratives, one thatis hermaphrodite friendly, is proposed. It maintains that complexdemonstratives such as `that female/male' and the pronoun `s/he' can succeed in referring to someone independently of his or her gender.This theory incorporates: (i) a multiple proposition view, i.e., theview that an utterance of a sentence containing a complex demonstrativeexpresses two (or more) propositions, namely the background proposition(s)and the official one; (ii) that the referent of a complex demonstrativeis a component of the official proposition expressed whether it satisfiesthe nominal part of the demonstrative expression or not; (iii) that thenominal part of a complex demonstrative only affect the background proposition(s) and (iv) that the utterance inherits its truth-value onlyfrom the official proposition.     

Val Plumwood

Miller's reply to Nelson misses the point because it does not attend to the difference between identifying the truth conditions for a proposition and explaining why those conditions are the ones in which the proposition is true.     

Unity and the Frege–Geach problem

The problem of the unity of the proposition asks what binds together the constituents of a proposition into a fully formed proposition that provides truth conditions for the assertoric sentence that expresses it, rather than merely a set of objects. Hanks’ solution is to reject the traditional distinction between content and force. If his theory is successful, then there is a plausible extension of it that readily solves the Frege–Geach problem for normative propositions. Unfortunately Hanks’ theory isn’t successful, but it does point to significant connections between expressivism, unity, and embedding.     

Foley's Threshold View of Belief and The Safety Condition on Knowledge

This paper introduces a new argument against Richard Foley's threshold view of belief. Foley's view is based on the Lockean Thesis (LT) and the Rational Threshold Thesis (RTT). The former thesis is the claim that it is epistemically rational to believe a proposition if and only if it is epistemically rational to have a degree of confidence in that proposition sufficient for belief. The latter thesis is the claim that it is epistemically rational to believe a proposition if and only if it is epistemically rational to have a degree of confidence in that proposition that meets or exceeds a specified threshold. The argument introduced here shows that the views derived from the joint endorsement of the LT and the RTT violate the safety condition on knowledge in way that threatens the LT and/or the RTT.     

Credence and self-location

All parties to the Sleeping Beauty debate agree that it shows that some cherished principle of rationality has to go. Thirders think that it is Conditionalization and Reflection that must be given up or modified; halfers think that it is the Principal Principle. I offer an analysis of the Sleeping Beauty puzzle that allows us to retain all three principles. In brief, I argue that Sleeping Beauty’s credence in the uncentered proposition that the coin came up heads should be 1/2, but her credence in the centered proposition that the coin came up heads and it is Monday should be 1/3. I trace the source of the earlier mistakes to an unquestioned assumption in the debate, namely that an uncentered proposition is just a special kind of centered proposition. I argue that the falsity of this assumption is the real lesson of the Sleeping Beauty case.     

Liar-type Paradoxes and the Incompleteness Phenomena

We define a liar-type paradox as a consistent proposition in propositional modal logic which is obtained by attaching boxes to several subformulas of an inconsistent proposition in classical propositional logic, and show several famous paradoxes are liar-type. Then we show that we can generate a liar-type paradox from any inconsistent proposition in classical propositional logic and that undecidable sentences in arithmetic can be obtained from the existence of a liar-type paradox. We extend these results to predicate logic and discuss Yablo’s Paradox in this framework. Furthermore, we define explicit and implicit self-reference in paradoxes in the incompleteness phenomena.     

Are Propositions Essentially Representational?

Jeffrey King argues that nothing has truth conditions except by being taken to be true or false by rational agents. But – for good reason – King claims that propositions possess truth conditions essentially and intrinsically. I will argue that King cannot have both: if the truth conditions of a proposition depend on the reactions of rational agents, then the possession of truth conditions can't follow from the intrinsic nature or existence of the proposition. This leaves two options. Either, nothing can do the job that motivates positing propositions. Or, there is no need to explain what bestows a truth condition on a proposition.     

Attributions of responsibility for date and stranger rape

This study examined the effects of the victim-perpetrator relationship on college students' attributions of responsibility for rape. In addition, the rape specificity of these attributions was investigated. College females and males read one of six scenarios that depicted a rape or a proposition, and that varied according to the victim-perpetrator relationship (steady dating partners/acquaintances on a first date/strangers). Then they rated seven responsibility attributions for the rape or proposition. Results indicated that most forms of victim responsibility were stronger for the rape and proposition on a date than for the incidents between strangers, and the findings concerning the perpetrator's responsibility were mixed. The pattern of both victim- and perpetrator-responsibility attributions suggests that both a rape and proposition on a date, compared to incidents between strangers, elicit stronger sex role and sexual attributions. Moreover, male subjects, in comparison to female subjects, gave higher ratings to several responsibility attributions, and these, also, are linked to sex role and sexual considerations. Further, the data revealed that only the perpetrator-responsibility attributions were stronger for the rape than the proposition.This research was supported by the University of Connecticut Research Foundation Grant No. 1171-000-22-00215-35-760. The authors thank Laurin Hafner for his help with the data analysis.     

When Hyperpropositions Meet ...

With each proposition P we associate a set of proposition (a hyperproposition) which determines the order in which one may retreat from accepting P, if one cannot fully hold on to P. We first describe the structure of hyperpropositions. Then we describe two operations on propositions, subtraction and merge, which can be modelled in terms of hyperpropositions. Subtraction is an operation that takes away part of the content of a proposition. Merge is an operation that determines the maximal consistent content of two propositions considered jointly. The merge operation gives rise to an inference relation which is, in a certain sense, optimally paraconsistent.     

Truth Values and the Value of Truth

This paper explores the ways in which truth is better than falsehood, and suggests that, among other things, it depends on the kinds of proposition to which these values are attached. Ordinary singular propositions like "It is raining" seem to fit best the bivalent "scheme" of classical logic, the general proposition "It is always raining" is more appropriately rated according to how often it rains, and a "practically vague" proposition like "The lecture will start at 1" is appropriately rated according to its nearness to exactness. Implications for logic of this "rating system" are commented on.     

The Role of Consciousness in Grasping and Understanding

One sometimes believes a proposition without grasping it. For example, a complete achromat might believe that ripe tomatoes are red without grasping this proposition. My aim in this paper is to shed light on the difference between merely believing a proposition and grasping it. I focus on two possible theories of grasping: the inferential theory, which explains grasping in terms of inferential role, and the phenomenal theory, which explains grasping in terms of phenomenal consciousness. I argue that the phenomenal theory is more plausible than the inferential theory.