Mohammed Arkoun, who was the professor of Islamic Studies at the New Sorbonne University for many years, can be considered one of the most influential reformist thinkers of the contemporary Islamic world. In the light of his most fundamental views about the critique of the Islamic reason, he brought about many changes in the methodology of understanding of intellectual and cultural inheritance of Islam in most expert circles in the West and throughout the Islamic world. He writes in detail about this and says that the epistemological foundations and traditional analytical tools of Islam lack any kind of value today. From his epistemological standpoint, modern man, he says, sees them to be irrational. He emphasizes that traditional Muslim theologians and jurisprudents have erroneously been teaching that the Islamic reason is an absolute reason and that it is not connected to any historical contexts. In the same vein, he attempts to prove that the reason (that) the Qur'an mentions is simply a practical and empirical reason. In this article, by using the philosophical analytical method, we will examine the content of some of the most important works of Arkoun. In those, he has explained in detail his critique of the Islamic reason. While answering his criticism, we will explain that the Qur'an and the totality of the Islamic scientific inheritance gives cosmological value to the different levels of the reason and that it does not in any manner reduce truth and knowledge at the level of instrumental and empirical reason. We will talk about 11 types of reasons that have been mentioned in Islam. These are the following: conceptual reason, theoretical reason, practical reason, metaphysical reason, common sense, universal reason, particular reason, empirical reason, instrumental reason, intuitive reason and sacred reason. In contrast to Arkoun, who considers Western thought to be the standard by means of which one must reconstruct the Islamic reason, we will explain that in the West today most people have lost hope in modern enlightenment. More than this, modern instrumental science has lost its connection to all of the higher levels of the reason. Now, it follows the lower levels of rationality in which social and media power delineate its foundations and direction. We will come to the conclusion that the truth and the solution to the crisis of the modern world can only be sought out in the buried treasures of the sacred reason and the theoretical and practical reason of Islamic tradition and religion in general.