Arthur N. Prior, in the Preface of Past, Present and Future, made clear his indebtedness to “the very lively tense-logicians of California for many discussions”. Strangely, with a notable exception of Copeland (1996), there is no extensive discussion of these scholars (as a group, if not a school) in the literature on the history of tense logic. In this paper, I propose to study how Nino B. Coc...

some contemporary logicians have introduced a new simple method of logical consequences and reduced all immediate arguments to conversion and obversion. by dint of positive and infinite terms, one of the logicians, reza akbari, increased the four traditional quantified propositions to 32 ones: the 4 well-known positives, 4 subject-infinites, 4 predicate-infinites, 4 two-sided-infinites, and the...

In knowledge representation and reasoning systems, diagrams have many practical applications and are used in numerous settings. Indeed, it is widely accepted that diagrams are a valuable aid to intuition and help to convey ideas and information in a clear way. On the other side, logicians have viewed diagrams as informal tools, but which cannot be used in the manner of formal argumentation. Ins...

Fibromyalgia and chronic fatigue syndrome are disorders that often occur simultaneously and are characterized by widespread pain and persistent fatigue. The patients are associated with disability and impairment social and physical functions. There are many remedies in traditional Persian medicine suggested for management of the disease complaints. The aim of this study was to investigate the c...

athir al-din abhari is one of the most outstanding logicians of the islamic period, even though he is less known to contemporary scholars than other logicians. this article, by presenting an edition of al-risalat al-zahirah (the shining treatise), not only makes available for the first time in print an important text in the field of logic, but also surveys some of abhari's logical thought ...

By treating belief as a modality and combining this with problems about constant truth tel lers and constant l iars (knights and knaves) we obtain some curious epistemic counterparts of undecidability results in metamathematics. Godel's second theorem gets reflected in a logician who cannot believe in his own consistency without becoming inconsistent. Lob's theorem reflects i t se l f in a vari...