نشریه منطق پژوهی
سال یازدهم شماره 1 (بهار و تابستان 1399)

Through history many have challenged philosophy and logic. Ibn Timiya not only challenges Aristotlian/Avicennean philosophy, but their logic. He presented his discussions in details in many books, but in Arrado Alal Almanteqeen book, based on the the two-part conception of logic (concept and judgment) and discussing his two claims about each part of logic, he systematize his objections. This book has four sections: 1) Notion of desired is only possible through definition. 2) Definition is knowledge of conceptions. 3) Affirmation of desired is only possible through deduction. 4) Deduction or logical argument provides knowledge of affirmation. Ibn Timiya presents his ideas in two positive and negative ways, as 1 and 3 are negative and 2 and 4 are positive. According to Ibn Timiya neither positive nor negative claims of logicians are true. He provides eleven reasons against 1 and seven reasons against 2, mean while he objects to the components of definition. This paper deals with Ibn Timiya's general objections to Aristotlelian logic (based on some verses from Quran) and also his (positive and negative) objections to the conception part of the Aristotelian logic. At times, he compares these with some empiricist philosophers. In addition to his objections, his main claims against essentialism and rejection of distinction between essense and attributes and rejection of the distinction between conception and judgment are discussed.

From the beginning of the emergence of new logic, fundamental links have been established between logic and various branches of mathematics, which led to solving mathematical problems and, conversely, solving basic problems in logic itself. One of the challenges of the logical methods in the study of mathematical structures is the impossibility of studying some of the important structures of mathematics, including analytic structures, in the framework of the first-order language and logic. The main purpose of this paper is to provide a suitable logic for studying these structures and then solving problems in the analysis using logical tools. At the beginning of this article, we will briefly review some suitable logics for studying the structures in mathematical analysis, and will outline some of the most important uses of logic in analysis. Then we present and prove one of the recent achievements, which is an important application of logic in analysis. In particular, we study the concept of definability in logic and its relation with mathematical analysis.

Definition and category of fallacies differs in works of philosophers and logicians. In this article after a short report of this issue, a new definition and category has been presented for fallacies and on this base, the role of ordinary argument or enthymematic has been highlighted. Enthymematic is an argument with one sentence as introduction from which the conclusion is achieved. As logicians say, major premise is omitted in enthymematic and in many cases it is for hiding the false of major premise. Because the mentioned point has example in many fallacies, the golden key for identifying fallacies is so designed: Reconstruction of the first argument, adding the major premise in form on a conditional proposition, generalizing the conditional proposition, and doubting about its truth. In continuation twenty examples have been chosen from books of teaching fallacies to show successfulness of golden key. Finally there is a list of more than fifty Identifiable fallacies whit this method, mentioning this important point that identifying fallacies with golden key has many advantages in comparison with the common method of introducing different fallacies one by one.

Avicenna's innovation on Conditional Categorical Syllogism is known as a turning point in Islamic logic. Conjunctive conditional syllogism is accepted as valid; but there are some problems and different opinions about Disjunctive syllogism. In his works, He mentions various conditions to determine the truth-value of Alternative syllogism and considers the Exclusive disjunctive syllogism as invalid. Following Avicenna's thoughts, Nasir al-din Tusi declares the Exclusive disjunctive syllogism invalid and holds that syllogism consists of two disjunctive propositions that are not valid either. Agreeing with some of the general conditions of the syllogism, other contemporary logicians namely Afzal al-din Khunaji and Siraj al-din Ormavai declares the two types as valid. It seems that the only way to solve the disagreement between the logicians on this issue is to change premises into the conjunctive syllogism and then follow the rules of conjunctive and finally reach the conclusion through changing Conjunctive into Disjunctive Syllogism.

In this article, which is written in the field of Aristotle logic in general and absolute Syllogism in particular, the aim is to present a new method for representing predicative propositions by considering the negative terms on the developed Vann diagram. This method is capable of displaying and inferring all possible results from two premises in all forms with any combination of negative and positive terms. It is also able to infer all the equations of each predicative proposition. This method is easy and decidable and having high expressive power. Conventional diagrammatic methods are either incapable of representing syllogism with negative terms or, if able to work with negative terms, do not have the desired visual representation that is the main purpose of diagrammatic representations. This method uses three-value valuation of lines and surfaces on a vann diagram, and the representation of each proposition is done by drawing a two-part arc.

In this paper,, I will first introduce the ontological view of Wittgenstein as it appears in the Tractatus. He starts his ontological discussion with the discussion of facts, which he then clarified by appealing to the notions of state of affairs and simple objects. I will then discuss his semantic view, which is based on his Picture Theory of Language, which brings in the notion of propositions. In such an analysis, he appeals to the notion of basic or elementary propositions and names. In his view, there is an isomorphic relationship (actually correspondence) between the logical structure of language (and its mental counterpart, thought) and the world. It is only in such a relation which a proposition can gain any meaning, or Sense. In this paper, I will investigate the relationship between the early Wittgenstein's ontological and semantic views and the way these views are related to other basic logical ideas in the Tractatus.

Intuitionistic logic is a non classical logic obtained by omitting the axiom of excluded middle from classical logic. This logic was created by philosophical motivation towards the foundation of mathematics. There are several semantics for intuitionistic logic (such as Kripke semantics, neighborhood semantics and topological semantics) that are sound and complete. In this paper, we first present two new neighborhood semantics for propositional intuitionistic logic (IPC). Then we establish soundness and completeness of IPC with respect to these new neighborhood semantics. The relation between neighborhood and topological semantics are also investigated. One of these new neighborhood semantics is introduced with a somewhat more complex definition than the usual neighborhood semantics which was introduced before. This semantics is called NB-neighborhood semantics. In order to establish completeness with respect to NB-neighborhood semantics for IPC, first we need to introduce a system WF of subintuitionistic logic, weaker than Corsi's basic subintuitionistic system F.

Non-contradiction Paradox that challenges the most impotant principle of knowledge, assuming that “the aggregation of the pair of contradictories is impossible” concoludes that that “the aggregation of the pair of contradictories is not impossible”. Mulla Sadra tries to solve the paradox by distinction between two type of predication called ‘awwali’ and ‘shayi’. He presupposes a subject-predicate structure in these proposisions. Denying such a presupposition, this article suggest another solution. Non-contradiction Paradox that challenges the most impotant principle of knowledge, assuming that “the aggregation of the pair of contradictories is impossible” concoludes that that “the aggregation of the pair of contradictories is not impossible”. Mulla Sadra tries to solve the paradox by distinction between two type of predication called ‘awwali’ and ‘shayi’. He presupposes a subject-predicate structure in these proposisions. Denying such a presupposition, this article suggest another solution. Non-contradiction Paradox that challenges the most impotant principle of knowledge, assuming that “the aggregation of the pair of contradictories is impossible” concoludes that that “the aggregation of the pair of contradictories is not impossible”. Mulla Sadra tries to solve the paradox by distinction between two type of predication called ‘awwali’ and ‘shayi’. He presupposes a subject-predicate structure in these proposisions. Denying such a presupposition, this article suggest another solution.

The problem of existential commitment is how and to what extent we are committed to accept the existence of certain objects in the world and especially the objects we talk about because of our use of language. “Geach’s Puzzle” which is an interesting and famous problem in existential commitment induced by an anaphoric text is a general problem about the existential commitments of the third speaker (narrator) in a discourse with more than two speakers. The solution defended in this dissertation is that if the first two speakers speak of an object which didn’t initially exist, they have actually created it as an abstract mythical object. Now, the third speaker can commit himself to accept the existence of that object while reporting what those two speakers had said without any need to agree with the properties they had ascribed to that object. The object indeed exists, because it was created in a myth.

In this article, we research this issue: The problems of the proviso of modal opposition between the contradictory propositions. Most of the logicians in Islamic world have accepted the modal opposition as a proviso of contradiction between two modal propositions. In their opinion, if two contradictory propositions had a common modality, we should deny either the Law of Non-Contradiction or the Principle of Excluded Middle. So, there is no choice but opposition in “Modality”. In this paper, I want to show that the sameness of modalities has no problem; and contrary to what the logicians thought, it is the modal opposition that leads to deny the Principle of Excluded Middle. From the point of view of this paper, the root of the mistake is confusion between ‘necessity of negation’ and ‘negation of necessity’ (as well as between ‘perpetuity of negation’ and ‘negation of perpetuity’). So, the modal sameness is needed for contradiction, not the modal opposition.

Easiness in teaching is one of the educational principles in science. Observance of this principle in discovering, defining, explaining, reasoning, and explaining the results, helps us to accelerate learning. Logic, which claims to measure and correct thought, Must be more observant of this principle than other sciences. But it seems that, the naming of modal proposition in traditional logic is less committed to this principle. This method of naming in the early stages of education, reduces the desire of the logic student to continue the discussion in modal Logic, and will lead to the isolation of modal Logic in traditional logic schools. So, the research question is: what is the critique of the traditional modal Logic method in naming modal proposition? And how can we change this method to make it easier to teach logic? In this article - analytically - we have criticized the naming method of modal proposition in traditional modal Logic. And we have shown that how can we use proper names in naming modal proposition. This way, reduced the difficulty of naming modal proposition in traditional modal Logic.

I will argue that the more advanced semantic paradoxes do not cause any trouble with Tarski's solution to the liar paradox, i.e. drawing a hierarchical picture of language, but that they even go further to provide guidance for discovering the true structure of metalanguage. Paradoxes arise when we presuppose a global layered structure for language. Metalanguage should not be considered as the upper layer of language, but rather as a defined topology on object language, which allows for a variety of hierarchical structures. In this more exact picture of metalanguage, Tarski's conception of truth must be construed as a local one, i.e. truth as a local predicate. This approach may shed some light on the less explored aspects of semantic paradoxes, especially Yablo's paradox. I will discuss that by considering a circular topology, a non-self-referential and non-paradoxical model can be obtained to locally attribute truth and falsehood to Yablo's expressions.