Ibn Taymiyyah, in particular, emphasized this, classifying him among the deniers of attributes, the Mu'tazilah, and others. He says: "When Allah the Almighty supported the people of Sunnah and the Community and aided them, this denial remained in the hearts of many of their followers. So they began to appear at times with the Rafidah, Qaramitah, and Batiniyyah, and at times with the Jahmiyyah and the unionists. At times they agreed with them that He is absolute existence, and nothing more. And the author of Al-Murshidah [i.e., Ibn Tumart] had this creed. He stated this in a large book in which he explained his doctrine on this matter. He mentioned in it that Allah the Almighty is absolute existence, as Ibn Sina and Ibn Sab'in and their like say. And he says in the same context: 'He limited himself in it [i.e., Ibn Tumart in Al-Murshidah] to what agrees with his principle, which is the saying that Allah is absolute existence, and this is the saying of the philosophers, the Jahmiyyah, the Shi'ites, and their like. He mentioned in it what the deniers of attributes say, and he did not mention a single affirmative attribute of Allah the Almighty."

It is clear from these sayings that Ibn Taymiyyah considers the Mahdi to be among the deniers. He bases this on two things: First, his belief in the idea of absolute existence, which is attributed to the deniers of attributes. Second, his failure to mention the affirmative attributes of Allah the Almighty.

Al-Subki also went to this extent in his Tabaqat, saying about the Mahdi: "Then he compiled books for them on knowledge, including a book he called 'The Most Sought-After Thing,' and creeds according to the doctrine of Al-Ash'ari on most issues, except in the affirmation of attributes, for in that he agreed with the Mu'tazilah in denying them, and in a few other issues." However, in another place, he absolves him of the accusation of Mu'tazilism attributed to him, saying: "As for his claim that Ibn Tumart was a Mu'tazili, that is not correct according to us. And it is most likely that he was an Ash'ari with correct creed." And we can lift what appears to be the case.

Philosophers go to the extent of denying attributes and do not affirm anything for Allah except absolute existence. Al-Razi says: "Abu Ali Ibn Sina went to the extent that Allah the Almighty has no reality except existence, which is qualified by being non-incidental to essence." See Usul al-Din, and especially Al-Shifa: Ilahiyyat, and Al-Isharat wa al-Tanbihat. Ibn Sina, 3/56, 3/602. Ibn Taymiyyah, Majmu' al-Fatawa, 11/484, 11/486. Al-Subki, Al-Tabaqat, 6/117.