MANTEQ-PAZHUHI (LOGICAL STUDIES)
Year:2018 | Volume:9 | Issue:1 |Papers Count:6

The incompatibility between the connectives of natural language and the language of classical logic in the truth-functionality has led some to think that the language of classical logic is incapable of representing the natural language sentences and formulating the arguments of this language. This paper tries to show that the language of classical logic is not entirely incapable of that formulation, and the opposition's claim to the ability of the language of logic in representing the sentences and the arguments of the natural language is not complete. The defenses in this area are divided into two categories of direct and indirect defense. Although Grice's theory is a turning point for indirect defense, this paper deals with some of direct defense against defenders of the incompatibility of formalized arguments in the language of classical logic with natural language: first, with Strawson's arguments in opposition to the representation of natural language sentences by classical logic, we propound Clark's defense, and then we will see young's challenges against Clarke and Clarke's responses.

Supposition theory is one of the most important logical-semantic theories which is put forward by medieval logicians in their logical texts and commentaries usually under the discussion topic "Properties of Terms". Since this theory has important consequences and results in logic, philosophy and theology, in this paper we will investigate its conceptual and historical origin. We claim that there is a significant and deep (historical and conceptual) bound between the medieval theory of supposition and Aristotle’ s theory of fallacies as he has stated in his treatise “ sophistical refutations” . The case-by-base study of Aristotle’ s fallacy in comparison to the semantical analysis of medieval logicians support this idea that supposition theory is the implicit semantic of Aristotle’ s “ sophistical refutations” which has been reinterpreted as an explicit and dependent field of study by medieval logicians, and also it has been extended throughout the late medieval ages due to different semantical problems.

When Saul Kripke published Semantical Analysis of Intuitionistic Logic I in 1965, all previous matters, Brouwer– Heyting– Kolmogorov interpretation (BHK interpretation), topological interpretation, Beth models, were effected by its clarity and perspicuity and then it became the standard, easy to understand and quite useable semintics for intuition logic of the Brouwer-Heyting. Since then very much research, books and papers was done in to clarify, understand and facilitate the paper. Kripke wrote this paper while he was at the end of the decade of fertile thinking in modal logic and its semantical analysis and publishing very creative 6 papers that completely changed the insight of modal logic. In Semantical Analysis of Intuitionistic Logic I, for designing an analysis for semantcs of intuitionistic logic he used his own method in modal logic and Cohn’ s, American mathematician, notion of forcing.

Identity is one of the most important and at the same time controversial topics in Frege’ s writings. In this essay we discuss his account of this subject and try to explain and criticise it’ s different interpretations. Our main question is about the elements that Identity is a relation between them. First of all we explain Frege’ s view of Identity in “ Begriffsschrift” (Conceptual Notation). The last considerations of Frege about this subject are represented in another well known work of him which is called “ Ü ber Sinn und Bedeutung” (On Sense and Reference), therefore in the next section we examine the concept of identity in this essay. The aim of this essay is not criticizing the view of Frege, but primarily to understand it, because that is the only way that we can grasp crucial issues like the essence of number in “ Die Grundlagen der Arithmetik” (Foundations of Mathematics) and Russell’ s paradoxes concerning the fifth axiom of “ Grundgesetze der Arithmetik” (Basic Laws of Arithmetic).

Hilary Putnam (1926-2016) in most of his philosophy focused on the question ‘ how does mind/language hook onto the world? ’ He followed this question and proposed various opinions in different fields of philosophy. In semantics, he defended semantic externlism and in metaphysics and ontology, he criticized metaphysical realism through two arguments including model-theoretic argument. Here I will show that Putnam’ s argument for semantic externalism and his model-theoretic argument, while are different in field, structure, and formulation, have been supported by a common thought concerning the relation between mind/language and the world. To achieve this goal, firstly I will introduce both arguments and propose new formulations for them. Secondly, I will enumerate five similarities between these formulations, and finally, on the basis of these similarities, I will propose the supporting thought formed as an argument. According to this supporting thought, the strict separation between mind and the world leads to indeterminacy of referential relation between them; but our common sense and realistic intuition implies that this relation is determined; therefore, mind and the world are not strictly separated; i. e. are interpenetrated.

Aristotle commences controversial debate with introducing three figures of syllogism. Then, the fourth figure was added to syllogism. In contrast to the other three figures which have a few discuses, the fourth figure has a lot of discussion and disagreements about conclusion conditions. Three controversial difference can be seen in this figure: (1)The worth of it (2) The conclusion conditions (3) the valid types of fourth figure. Some logician Before Athir al-Din al-Abhari (from Ibn Salah Hamedani to Afzal al-Din Khaneji), which are called antecedents accepted five valid types of the fourth figure under specific conditions and some logicians after him accepted eight valid types. It is worth mentioning that Abhari in some circumstances added three valid types to the five accepted types of fourth figure. Some of logicians after him (Taftazani, Hajj Molla Hadi Sabzavari) accepted eight types without any attention to these circumstances. We investigate the background of the fourth figure and its conditions. After approving the primary idea, we concentrate on the rootes of this mistake and show that the misunderstanding about Abhari’ s phrases was caused the expansion of his idea in modality syllogism to syllogism in general.