Tautology in Treatise on Categorical Propositions from Viewpoint of Muslim Logicians and Western Philosophers

Tautology is a sort of proposition that dates back to Aristotle. The most important questions about it consist of: 1. Does tautology have the minimum qualifications for being a proposition? 2. Does this proposition tell us anything about the external world? And 3. What is the relation between this proposition and the principle of non-contradiction and which one is prior to the other in terms of logical foundations? Muslim logicians have dealt with such propositions under ''haml al-shay ala nafsihi''، whereas Western philosophers have treated it as «tautology» or «analytic propositions.» The way Mudarris Zinoozi has dealt with this predication and shed light on its problems is particularly noteworthy. After studying Muslim philosophers and logicians'' views، the author analyzes Zinoozi''s views، comparing Muslim logicians'' view with those of Western philosophers. He has also made his own contribution as he touches every important issue.