Explanation of Difference of Opinion of Avicenna on the Problem of the Union of Intelligent with Intelligible

There is a duality in Avicenna''s viewpoint in different works of him in rejecting or accepting of the union of intelligent and intelligible. And this fact has provoked some people to believe that there is conflict and in consistency in his views. Since on the one hand in his book Shifa and Isharat he has opposed them، and on the other hand in his book Mabda and Ma''ad he defends the theory of union of intelligent and intelligible and demonstrates it. That what is the source of this conflict or wether truly there is a conflict or not، is the problem which the writer has tried to study by the analysis of some evidences implying the rejection or proving the problem by Avicenna in the present article. Finally، this research has come to this conclusion that there is no conflict and the reason for different views of Shaykh in rejecting or acceptance of this union، goes back to his two kinds of essential and existential attitude.