He finally concluded that there was no rational way to refute skeptical doubt, but that there was another way to discover truth, one hinted at by the prophet Muhammad and the sages within the Sufi tradition, the mystical side of Islam. But for the next five years he was gripped in a spiritual crisis, trying to find a rational foundation for Islam’s basic principles as outlined in the Qu’ran. He was appointed Professor of Theology at the University of Baghdad at the tender age of thirty-three. One of al-Ghazali’s nicknames is “The Proof of Islam,” and he is called that not only because of the sagacity of his writings, but because of the quality of the life he lived.
The ultimate ecstasy, al-Ghazali contends, is not found in any physical thing, but rather lies in discovering through personal experience one’s identity with the Ultimate Reality. In this we see some of his core ideas: that happiness consists in the transformation of the self, and that this transformation consists in the realization that one is primarily a spiritual being. Indeed, his monumental Revival of the Religious Sciences, which runs over 6000 pages and 4 volumes, was reprised as a shorter text in Persian, labeled the Alchemy of Happiness. What most people don’t know, however, is that al-Ghazali wrote extensively on the topic of happiness.