One of Kripke’s innovations concerning the philosophy of language is the doctrine that the truth of some metaphysically necessary propositions is only known a posteriori. The typical example he gives is the identity statement consists of two different proper names that refer to the same referent, like “Hesperus = Phosphorus”. By metaphysically necessary he means that the proposition is true in all possible worlds and by a posteriori knowledge he means that its truth is known by experiment or investigation. Some (...) philosophers have given arguments against Kripke’s doctrine and claimed that such propositions can, also, be known a priori. In this paper, I will defend Kripke’s view by showing that his approach to the issue is linguistic not metaphysical, opposite to his critics. (shrink)

According to Aristotelian logic, in categorical logic, there are three kinds of judgements (qaḍīyya): affirmative, negative, and metathetic (ma‘dūla). Khūnajī, a famous Muslim logician in the 13th century, introduces a different judgement (or statement) entitled “affirmative judgement with the negative predicate” (mūjiba al-sāliba al-maḥmūl; henceforth, ANP judgement). Although in the Arabic language, formally, ANP judgement is similar to definite negative (sāliba muḥaṣṣala) and also metathetic judgements, the way of its construction is different from both of them and its truth conditions (...) are different from metathetic ones. From a modern logic viewpoint, ANP may indicate equality judgement; however, attributing it to Muslim logicians is questionable, although some of their wordings may implicitly show it. According to Ḥāʾirī, an Iranian contemporary philosopher and logician, the new judgement is supposed to solve some problems, especially logical explanation of the division of modalities into necessity, impossibility, and contingency (imkān khāṣṣ). However, Ṭabāṭabāʾī, another Iranian contemporary philosopher, disagrees with Ḥāʾirī and regards ANP judgement the same as an affirmative metathetic one. In this paper, while examining Ṭabāṭabāʾī’s and Ḥāʾirī’s reasons, by using some insights into modern logic, I will try to strengthen Ṭabāṭabāʾī’s views, although it may be confronted with some questions or deficiencies. (shrink)

According to a rule of traditional logic concerning the relation between general (or universal) concepts, if a given concept is more general than a second one, then the opposition (or contradictory) of the first concept is more specific than the opposition (or contradictory) of the second one. Kātibī, one of the Muslim logicians in the 13th century, has raised a question against this rule and, by giving some counterexamples, claims that it results in contradiction. Some Muslim logicians have replied to (...) Kātibī, and in this paper I have examined their replies. Also, by using rules of modern logic, we may easily show that either Kātibī's argumentation is fallacious or it does not result in contradiction; however, it seems that if modern logic rules had been represented to Muslim logicians, some of those rules would have been rejected by them. (shrink)