Truth Analysis of the Gettier Argument

Gettier (1963) presented the now famous Gettier problem as a challenge to epistemology. The methods Gettier used to construct his challenge, however, utilized certain principles of formal logic that are actually inappropriate for the natural language discourse of the Gettier cases. In that challenge to epistemology, Gettier also makes truth claims that would be considered controversial in analytic philosophy of language. The Gettier challenge has escaped scrutiny in these other relevant academic disciplines, however, because of its façade as an epistemological analysis. This article examines Gettier's methods with the analytical tools of logic and analytic philosophy of language.     

时间压力和相似性对类比推理直觉加工的影响

通过两个实验探讨了时间压力对类比推理的直觉加工的影响。实验1采用三因素混合实验设计,以48名大学生为被试,在不同时间压力条件下对不同相似性言语类比推理题进行喜好度判断和类比推理逻辑判断。实验2是在实验1的基础上用图形类比推理题代替语义类比推理题,以56名大学生为被试。结果发现:(1)时间压力下,对跨领域言语类比推理的直觉加工效应显著高于逻辑加工效应;(2)时间压力下,低难度图形类比推理题的直觉加工效应显著高于逻辑加工效应。无时间压力条件下,图形类比推理的逻辑加工效应优势明显;(3)时间压力对类比推理的直觉加工和逻辑加工均有影响     

Temporal logics for concurrent recursive programs: Satisfiability and model checking

We develop a general framework for the design of temporal logics for concurrent recursive programs. A program execution is modeled as a partial order with multiple nesting relations. To specify properties of executions, we consider any temporal logic whose modalities are definable in monadic second-order logic and which, in addition, allows PDL-like path expressions. This captures, in a unifying framework, a wide range of logics defined for ranked and unranked trees, nested words, and Mazurkiewicz traces that have been studied separately. We show that satisfiability and model checking are decidable in EXPTIME and 2EXPTIME, depending on the precise path modalities.     

Duality and Canonical Extensions of Bounded Distributive Lattices with Operators,and Applications to the Semantics of Non-Classical Logics I

The main goal of this paper is to explain the link between the algebraic and the Kripke-style models for certain classes of propositional logics. We start by presenting a Priestley-type duality for distributive lattices endowed with a general class of well-behaved operators. We then show that finitely-generated varieties of distributive lattices with operators are closed under canonical embedding algebras. The results are used in the second part of the paper to construct topological and non-topological Kripke-style models for logics that are sound and complete with respect to varieties of distributive lattices with operators in the above-mentioned classes. This revised version was published online in June 2006 with corrections to the Cover Date.     

An Early Buddhist Text on Logic: Fang Bian Xin Lun

The Fang Bian Xin Lun is a text on Buddhist logic which is thought to be the earliest one still to be extant. It appears in Chinese only (T1632). The great Italian indologist Giuseppe Tucci, believing that the text was originally a Sanskrit text, translated it into Sanskrit and gave it the title Upāyahṛdaya. The paper provides the historical background of the development of logic in Classical India up to the time of this text, summarizes its content and translates its first section.

Is it always fallacious to derive values from facts?

Since the time of David Hume, many philosophers have held that there is a logical Is/Ought gap. According to the doctrine of the Is/Ought gap, there are no valid (i.e., non-fallacious) arguments from purely factual premises about whatis the case to moral or normative conclusions about whatought to be. Occasionally, this doctrine has been challenged, but frequently it has been accepted without argumentation. Charles Pigden has recently argued for a logical Is/Ought gap on the grounds of the conservativeness of logic. I offer a counter-example which shows that Pigden's argument is unsound and that there need be no logical gap between Is-premises and an Ought-conclusion. My counter-example is an argument which is logically valid, has only Is-premises and an Ought-conclusion, and does not purport to violate the conservativeness of logic. Moreover, my argument does not rely, as other alleged counter-examples do, on controversial assumptions from Aristotelian biology about natures or ends, or about institutions such as promise-making.     

From Modal Discourse to Possible Worlds

The possible-worlds semantics for modality says that a sentence is possibly true if it is true in some possible world. Given classical prepositional logic, one can easily prove that every consistent set of propositions can be embedded in a ‘maximal consistent set’, which in a sense represents a possible world. However the construction depends on the fact that standard modal logics are finitary, and it seems false that an infinite collection of sets of sentences each finite subset of which is intuitively ‘possible’ in natural language has the property that the whole set is possible. The argument of the paper is that the principles needed to shew that natural language possibility sentences involve quantification over worlds are analogous to those used in infinitary modal logic.     

Expansion and Contraction of Finite States

We present a theory that copes with the dynamics of inconsistent information. A method is set forth to represent possibly inconsistent information by a finite state. Next, finite operations for expansion and contraction of finite states are given. No extra-logical element — a choice function or an ordering over (sets of) sentences — is presupposed in the definition of contraction. Moreover, expansion and contraction are each other's duals. AGM-style characterizations of these operations follow.     

Vagueness and Blurry Sets

This paper presents a new theory of vagueness, which is designed to retain the virtues of the fuzzy theory, while avoiding the problem of higher-order vagueness. The theory presented here accommodates the idea that for any statement S ₁ to the effect that Bob is bald is x true, for x in [0,1], there should be a further statement S ₂ which tells us how true S ₁ is, and so on – that is, it accommodates higher-order vagueness – without resorting to the claim that the metalanguage in which the semantics of vagueness is presented is itself vague, and without requiring us to abandon the idea that the logic – as opposed to the semantics – of vague discourse is classical. I model the extension of a vague predicate P as a blurry set, this being a function which assigns a degree of membership or degree function to each object o, where a degree function in turn assigns an element of [0,1] to each finite sequence of elements of [0,1]. The idea is that the assignment to the sequence 0.3,0.2, for example, represents the degree to which it is true to say that it is 0.2 true that o is P to degree 0.3. The philosophical merits of my theory are discussed in detail, and the theory is compared with other extensions and generalisations of fuzzy logic in the literature.