In al-Tahbīr (1) it is stated: He was a native of Shahristānah, an authority in the principles of jurisprudence, well versed in belles-lettres and in those disciplines that had fallen into neglect.
He is, however, accused of godlessness and of going to extremes in his Shi‘ite leanings.

Ibn Arslān says in The History of Khwārizm: “He was an intelligent, many-sided scholar. Had it not been for his inclination toward the irreligious and his doctrinal confusion, he would have been the leading imam. We were often amazed that, with all his abundant merit, he should incline to something that has no foundation whatsoever! We seek Allah’s protection from such abandonment. This happened only because he turned away from the knowledge of the Sacred Law and busied himself with the darkness of philosophy. There were debates between us, yet he persisted in championing the philosophers’ doctrines and defending them. I attended his sermons many times, and there was in them neither ‘Allah said’ nor ‘the Messenger said.’ One day someone asked him, ‘The other scholars discuss legal questions in their gatherings and answer them with the words of Abū Ḥanīfa or al-Shāfiʿī, but you do not do that. Why?’
He replied, ‘My case and yours is like that of the Children of Israel: manna and quails came down to them, yet they asked for garlic and onions…’ (al-Baqara 2:61).”

Ibn Arslān goes on: He died in Shahristānah in the year 549 AH (3). He had performed the pilgrimage in 510 AH and delivered sermons in Baghdad.

195 – ʿAbbāsah, Abū Muḥammad al-ʿAbbās ibn Muḥammad ibn Abī Manṣūr*
The preacher and scholar, Abū Muḥammad al-ʿAbbās ibn Muḥammad ibn Abī Manṣūr.