This is further illustrated by the fact that the philosophers known to have departed from the religion of Islam were followers of Mubashshir ibn Fātik, one of their emirs, and Abū ‘Alī ibn al-Haytham. Both lived near al-Azhar Mosque under those rulers. Ibn Sīnā, his son, and his brother were followers of these two.
Ibn Sīnā said:
“I studied some philosophy, and I used to hear my father and brother discussing ‘the intellect’ and ‘the soul.’”
He lived during the reign of al-Hākim. Al-Hākim’s conduct is well known, as is what Hashkīn al-Durzī did at his command: calling people to worship al-Hākim, fighting the people of Egypt over this, and then going to Syria, where he eventually led the people of Wādī al-Taym ibn Tha‘laba astray. Heresy and hypocrisy persist among them to this day. They possess the books of al-Hākim; I obtained these from them and read what they contain concerning their worship of al-Hākim, his releasing them from the obligations of prayer, zakat, fasting, and pilgrimage, and their branding as Hashwiyya those Muslims who affirm these obligations and prohibit what Allah and His Messenger have forbidden. They contain countless other forms of hypocrisy of this kind.
In short, the “esoteric knowledge” they claim consists of disbelief in Allah, His angels, His books, His Messengers, and the Last Day. Indeed, it encompasses every form of disbelief. Yet they differ in degree: they are not all equal in disbelief. They divide this knowledge into seven levels, addressing a particular group of people at each level according to their distance from or closeness to religion.
They have titles and hierarchies assembled from the doctrines of the Magians, the philosophers, and the Rāfida, such as their expressions “the Preceding One” and “the Following One,” which they make correspond to “the intellect”