نشریه منطق پژوهی
سال هشتم شماره 1 (بهار و تابستان 1396)

Cobreros et al. (2012) developed a theory of vagueness in order to model tolerance principles coherently, in the sense that not everything falls under a vague predicate and no sorites paradox is valid. It is argued in this paper that their characterization of tolerance principles does not match with the standard conception of tolerance in the literature. In addition, their theory validates a stronger version of tolerance which suffers from clear counter examples. Furthermore, their theory validates tolerance just in a weak sense. That assimilates their theory with dominant theories of vagueness, those which accommodate tolerance principles not as true.

Ali Wahidiyan Kamyad claimed in an article named “Methodology of Usage of Fuzzy Logic in Islamic View” that fuzzy logic is a part of the logic of sacred Quran. This claim was supported by a group of researchers, while it seems that the evidences to prove it are incomplete. So it seems necessary to study the main claim again. What will be come at the continuing contains some critiques to this claim with respect to the Quranic evidences for which has been given. Besides some partial critiques to the correspondence of the Quranic examples which are claimed to be corresponded to the fuzzy argument given, it will be shown that there is a main fault in the claim that Quran has used in some verses the fuzzy logic which is based on a confusion of what is explicitly occurred in the passage as an argument (Mansus argument) and what is in ascribed to the passage by the reader (Mustanbat argument).

Kripke in his famous book, Naming and Necessity, introduces the concept of “rigidity” for designation of singular terms; and by using it, he refutes the Descriptive Theory of Meaning. If a term is rigid it means that it designates the same thing in all possible worlds in which it exists. Kripke, in third lecture, extends the concept of “rigidity” to all natural kind terms. This extension has had several interpretations which can be put into two categories: the sameness in designation, and the essentialist approaches. The sameness in designation approach, however, confronts “the trivialization problem”,i.e. not only natural kind terms, but also all general terms are rigid designators since each of them designates a property which remains the same across all possible worlds. An argumentative way has been proposed to refute trivialization problem. This approach is based on considering abundant objects as the designatum of singular terms and parallelism between these words and general terms. In this paper we will criticize this approach and show that it conflicts with some semantic roles of general terms and also our intuition concerning the truth value of sentences containing them.

The purpose of current article is to report and to analyze a part of the history of Exposition specially, and the history of logic in Islamic civilization generally. Aristotle uses the exposition in several places of his syllogistic, including in the proof of E-conversion. The problem of current article is the recent application. Since Theophrastus there have been many challenges in the proof of E-conversion by exposition. Alexander of Aphrodisias tries to resolve the challenges and, in order of it, propose two different interpretations about the mentioned exposition the second of which, on the basis of our analysis, is a reductio ad absurdum in which existential introduction, commutation, and existential elimination have been used. The fact shows that Aristotle’s logic, in this part, depends both on propositional and predicate logic. Again this interpretation considers the exposition as a non-syllogistic proof because of its usage from singular term, and shows that Alexander who counts the Aristotle’s syllogistic as the logic of universal terms is right. In Islamic world, Ibn Sina, Kunaji, and Tusi follow the same interpretation and even offer a more clear understanding of the mentioned rules, so that Ibn Sina and Tusi expressly talk about a distinction which today is made between proper name and arbitrary name. But Suhrawardi and Fakhr al-Din Razi who are influenced by Alexander’s first interpretation expose no brilliant acuity, not in understanding the nature of Aristotle’s logic, and not in understanding the rules involved in the proof of E-conversion by exposition.

Most of definitions presented for material/immaterial thing have a common form: first they define material thing, then they define immaterial thing as a thing that is not material. There is a common objection to these kind of definitions: all of them are such that we cannot define something between material thing and immaterial thing. In this research we try to investigate common definitions of material/immaterial thing, then web prove that according to Mulla Sadra's viewpoint about Substantial Motion of human soul, we should define some levels between pure material and pure immaterial, In fact there should be a spectrum beginning from pure material thing and ending to pure immaterial thing. Then we show that this new viewpoint to definition of material/immaterial thing (spectrum view) is not compatible with traditional definition system that uses Alhasr alAghi. Finally we propose a new approach toward definition of immaterial (and material) thing using fuzzy logic.

One of the most basic doctrines in the predicate logic is that existence can never be a predicate; rather, it is the particular quantifier. Here Ill try to explore the views of the founders of Fregean logic on the structure of the proposition, and why it does not take existence as a predicate. Then Ill state their explanation and solution for existential propositions. Finally, Ill investigate the shortcomings of their analysis. Many analytical philosophers, including Moore, Kneale, Wisdon, Ayer, etc, who have denied 'existence' as a predicate, have done so as part of their refutation of the ontological argument for the God's existence. However, here Ill deal only with Frege, Russell, and Quine. The other philosopher's stance can more or less be found in one of these three.