Why do we have to study for the Islamic philosophy? It seems that the concept of Islam is not compatible with that of philosophy. While the Islam is characterized by the religious dogmas based on the orthodox faiths, the philosophy is considered as the scientific methods which take the religious dogmas to pieces and therefore reach the level of agnosticism. How can these two heterogeneous elements be linked together by common interest? And why should Islam accept the philosophical methods even though there were the possibilities to destroy its own orthodox faiths? In this article I am trying to answer these questions. In my opinion the most important reason to study for the Islamic philosophy is that it gives more attention to the aspects of philosophy than those of Islamic theology. That is to say, I think that the Islamic philosophy was attempting to give universal metaphysical foundations to the Islamic cultures which were regional and narrow minded. Here I will examine the historical changes of the development of Islamic philosophy which gives us the broad horizon for the metaphysical thought of the Being. For this purpose I will consider all the historical steps for the unification of Islam with the Greek philosophy. Especially I focus on the concept of the Kalam which was playing a great role in this integration. Kalam is the most important starting point to explore the Islamic philosophy in the 8-9th century.