عنوان مقاله [English]
Ibn Sina in most of his logical works has added the stipuliation "remaining of falsity" to the definition of conversion, a stipulation that has been repeated in the logical works of thinkers such as Fakhr Razi and Abhari; but most logicians has challenged this procedure. For example, Khajeh Nasir Tusi believes that the above – mentioned stipulation has been generated by the scribe's mistakes.
In this article by emphasis on the existence of above-mentioned stipulation in six logical writings of Ibn Sina it is shown that this stipulation can not be ascribed to the scribe's mistakes. By proposing and evaluating the opposing and favourable reasons of this stipulation it will be evident that the acceptance of above - mentioned stipulation brings about inconsistency in the logical system of Ibn Sina. Within this article two solution have been proposed for resolving this problem. The first solution which has been formed on the basis of elimination of above mentioned stipulation has been offered by khajen Nasir and other logicians in later times, and the other solution which deals with the changing relation of conversion has been proposed by the writers of this article. It has also been shown that each of this two solutions has its own privileges and defects.