Logical Studies

Abstract Contextualism is the main opponent of minimalism. The debate between these two semantical approaches, stem in an old fashion dispute to determine the border between semantics and pragmatics. Contextualists claim that the sentences in the natural language are not truth-evaluable before being enriched pragmatically. In contrast, in minimalists’ viewpoint, there is a minimal semantic content that provides the truth-evaluable meaning of sentences in a way that context of utterance has limited effects on it. This contrast is based on the way and extent to which context affects semantic content. In this paper, after introducing these two approaches, the main arguments of contextualists against minimalist are discussed, then we show that minimalistic semantics like Kaplan's LD with objective interpretation of context cannot present any proper model even for sentences containing first-person reference, and on the basis of a subjective interpretation of context, the indexical/non-indexical distinction is not clear and other expressions of natural languages can be indexical, in a broad sense.

Abstract According to a favored version of inference to the best explanation (IBE), the hypothesis that provides the best explanation for a group of observed phenomena is probably true. One of the key objections against this line of thought is Voltaire’s objection. According to this objection, we have no reason to believe that the explanatory virtues, as the criteria for selecting the best explanation, provide the likeliest explanation. In this paper, we address probabilistic criteria which are subject to Voltaire’s objection in IBE. To be exact, we scrutinize this question: considering proposed probabilistic criteria for assessing the explanatory hypotheses as the criteria for selecting the best explanation, is it justified to think of the best explanation as the likeliest one? Dealing with this question, the probabilistic criteria will be analyzed in three group: criteria based on Bayes’ theorem, criteria based on confirmation theory and criteria based on explanatory virtues. We argue that none of these criteria can determine the best explanation which provides the likeliest one.

Abstract In Muslim’s logic of conditionals there is a consensus that the value of necessity conditional is defined by relationship between antecedent and consequent and not by the value of antecedent or consequent. However, in their opinions there are discussions on possibility of truth or falsehood based on value of antecedent and consequent. In some of the Muslim logicians’ texts beside of truth and falsehood a different status is mentioned with different terms such as probable false and true, unknown true and false, etc. Examining the nature of this status is the main question of the current text. In this paper, by reviewing different views of Avicennian logicians it’s shown that this classification is related to discussions on conditionals before introducing quantified conditional by Avicenna and Avicennian logicians attempted to accord it with quantified conditional, we showed that from the opinions of Avicennian logicians the opinions that don’t accept third condition as a participant of truth and falsehood are closer to the fundamentals of Avicennian’s logic.

Abstract The family resemblance’s theory of Wittgenstein is the most influential contemporary theory of, or, to put it more precisely, against “definition”. The theory’s main opposition is towards essential definitions, whose leading theoretician is known to be Aristotle. In modern era, This theory have been considered a challenge to essentialism. In this essay, after expressing the theory of family resemblance and backgrounds of those in opposition to the Aristotelian definition, By extracting criticisms of the theory to essential definitions and answers them according to the text of Aristotle, I’m trying to show that expressing such criticisms to the Aristotelian definition due wittgenstein’s misunderstanding and ignorance than the Aristotle’s essential definitions. To achieve this thesis, will be used of phenomenology and analytical methods. Examining the philosophers’ own works was among the investigation’s priorities.

Abstract In article of “social factors in mathematical and logical knowledge” The Author shows that social factors are determinant in logical and mathematical knowledge as differences of mathematicians, variety of contradiction in Reductio ad absurdum, deconstruction in infinite values, Wittgenstein`s analysis of Sum, change of the concept of evidence in history, Begging the question of proof of axioms, Begging the question of justification of logical rules by the value tables, Prior`s argument against formalists, absence of preference for psychological explanations against sociological ones, paradoxes of material implication, To appeal to intuition rather than reasoning, the critique of circular reasoning, conventionality of logical rules, harvest paradox …
In analysis of this evidences, first, I determined minimalistic evidences as the principle of contradiction, modus ponens, reductio ad absurdum. Second, I analyzed the cases as Infinite values, Wittgenstein`s point of view, value tables, Prior`s argument, convention,
Lack of necessity in obviousness of concepts in the obvious propositions, uncertain conceptions… At last I showed that social factors are not considered essential in logical and mathematical knowledge.

Abstract Sentential connectives in classical propositional logic, according to their definition, are truth function. Contemporary philosophers of logic and language propose two main theories regarding truth functionality of counterparts of the sentential connectives in natural language. Some (including Strawson 1952; Mitchel 2008; Young 1972; Read 1995) have argued that counterparts of the sentential connectives in natural language are not truth function; on the other hand, others (including Grice 1975; Clark 1971; Jackson 1979) propose arguments for their truth functionality. Grice's (1975) defense of truth functionality of conditionals ("if…then…") in natural language which is formulated on the basis of the ideas of assertability and implicature has had a central role in the literature of recent decades. The main goal of this paper is to consider and criticize Grice's defense of truth functionality of conditionals in natural language.