The signification of the statement "There is no efficient cause in the universal existence but Allah" is the verification of the unity of God in terms of His acts required from two conflicting foundations in the Asharite and Sadrite  schools of thought. The foundation of Asharites is the omnipotence of God resulting in the absolute negation of causality in the sense of necessity and in proving the complete free will of God in doing or not  doing all the voluntary and involuntary acts. In contrast, the foundation of Sadr al Mutaallihin resting on the principality of existence and its gradation, is the realization of causality and necessity in different grades of existence,and affirmation of hierarchical causes,hence proving the human being as the actual agent in his voluntary acts. On the other hand, MullaSadra proves the omnipotence of God based on the necessity of existence and the attributes of perfection in an infinite manner. Combination of these two views on the one hand involves the quality of admitting the complex issue of the hierarchical causality while accepting the omnipotence of God and considering Him as the exclusive agent in Sadrite thought.   It also enquires the relation of the foundations of this same principle in the two above mentioned schools of thought.

The main hypothesis of thepresent thesis is proving the hidden contradiction between the foundations of the very principle of" There is no efficient cause in the universal existence but Allah" in the two Asharite and Sadrite schools of thought . The possibility of the cross reference of the two foundations is ruled out based on the proof by reductio and absurdum. Since thestatement" There is no efficient cause in the universal existence but Allah" involves ahomonymic sense according to the both schools, and each one sticks to its own foundation, neither can be criticized by the foundations of the other. It is noteworthy that the present dissertation is not supposed to criticize the requirements or foundations of these two schools of thought due to their natural exclusion from the topic.

Keywords: Asharites, Sadr al Mutaallihin, potency, causality, efficiency, existence