those who say:

Only one person is correct in every foundational and subsidiary question, and everyone other than the one who is correct incurs sin because he is mistaken. In their view, error and sin are inseparable. This is the position of Bishr al-Marīsī and many of the Baghdadi Muʿtazila.

The second position is that if practical questions (1) are supported by decisive proof, whoever contradicts it is sinful and mistaken, just as in theoretical questions. If they are not supported by decisive proof, however, there is no underlying divine ruling concerning them; rather, Allah’s ruling with respect to each qualified jurist is whatever conclusion his independent reasoning leads him to. This group agreed with the first that error and sin are inseparable (2), and that everyone who errs incurs sin. However, they disagreed with them regarding questions subject to independent reasoning, saying:

There is no decisive proof in such questions.

In their view, probable belief rests on no evidence; it is merely akin to the soul inclining toward one thing rather than another. They therefore treated probable beliefs as a kind of volition and claimed that objective reality contains no [ruling sought through independent reasoning, nor does objective reality contain] (3) any indication weightier than another.

This is the position of Abū al-Hudhayl al-ʿAllāf and those who followed him, such as al-Jubbāʾī and his son. It is one of the two positions of al-Ashʿarī, and the better known of them. It was adopted by Qadi Abū Bakr al-Bāqillānī, Abū Hāmid al-Ghazālī, Abū Bakr ibn al-ʿArabī, and those who followed them. We have discussed this at great length [elsewhere] (4).