[Ibn Taymiyyah’s commentary]
I say:
By “fundamental principles,” he does not mean their overt departures from the Sunnah, for al-Ash'arī opposed them in these matters, such as the vision of Allah, the Quran, and the divine attributes.
Rather, he means the rational principles of their speculative theology upon which they based their subsidiary doctrines that conflict with the Sunnah. One example is this principle upon which they based the temporal origination of the world and the demonstration of the Creator’s existence. This is their most fundamental principle. We have already presented the statements of Abū al-Husayn al-Basīrī and others on this subject, explaining that the principle upon which the Mu'tazilah built their discourse on the foundations of religion is this very principle mentioned by al-Ash'arī. Yet he disagreed with them over many of its implications and subsidiary doctrines.
Then many followers of the later scholars, such as the followers of the author of al-Irshād (Guidance), accepted the full implications of the principles he had conceded to the Mu'tazilah. They thus agreed with the Mu'tazilah on what those principles entailed, while opposing their own master, Abū al-Hasan, and the leading scholars among his followers. They denied the divine attributes known through revelation and Allah’s exaltedness, and interpreted the vision of Allah as an increase in knowledge—a meaning the Mu'tazilah did not dispute with them. They said:
“There is no disagreement in meaning between us and the Mu'tazilah. Their disagreement is only with the corporealists.”
Likewise, concerning the Quran, they said:
“The Quran which the Mu'tazilah say is created—we agree with them that it is created. However, we assert the existence of another meaning, which is one and eternal.”
The Mu'tazilah deny that this is even conceivable. Thus the Mu'tazilah and the philosophers, along with the majority of rational thinkers, came to denounce them for contradicting the clear dictates of reason and obstinately denying self-evident truths.