Abstract

The separation of Avicenna between Essence and Existence influenced logic and Arab and Muslim logicians in the Middle Ages among them Ibn al-Nafīs (1208-1288). Under this influence he contributed to the development of logic and especially the theory of the universal term. By means of the consequences of this analysis:-It has become possible to make a distinction between abstract concepts and formal concepts independent of any sensible reality, and hence the questioning of Aristotelian categories, that is to say the ability to conceive for Ibn al-Nafīs like Avicenna, subjects and predicates which are not necessarily words expressing or belonging to one of the Aristotelian categories.-The analysis of the universal proposition as a conditional proposition, which made easier the distinction between absolute proposition which has no existential implication, and the other which differ from the first by an affirmation of explicit existence.