Continuing the path of Neo-Platonic philosophers and Farabi, while accepting the framework of the Greek thought in reaching the truth of the beings in the universe through the rational knowledge in the framework of Aristotelian logics, Avicenna has attempted to present a certain interpretation of some fundamental concepts of the Greek thought and offer a metaphysics with quite rational and argumentative results as well as a rational interpretation for some of the principal concepts of the Quranic thought in the Islamic world, a metaphysics that can be called the essential Greek-Islamic rational system. The present article attempts to use an analytical-explanatory method to prove that, firstly, Avicenna accepts the Greek rational thinking method in reaching the truth of the beings, calling it the certitude wisdom and knowledge. And – in line with Aristotle – he introduces the man’s sensory faculty as the starting point for the path of acquiring certitude knowledge, through which he reaches the rational knowledge of the beings. Secondly, it states the most important axes of Avicenna’s philosophy in his legal reasoning reading of principles of Aristotelian thought.
