Reliable. See his biographical entry and the verification of his name in: • Al-Jarḥ wa-al-Taʿdīl by Ibn Abī Ḥatm, 2/2/161 (no. 743). • Tārīkh Baghdād by al-Baghdādī, 10/74–89. • Al-Lubāb by Ibn al-Athīr, 1/38. The editor (may Allah have mercy on him) of Darʾ Taʿāruḍ al-ʿAql wa-al-Naql commented in footnote (1) on vol. 1, p. 234: “In S [a certain manuscript] it reads: ‘Only Abū ʿAbd al-Raḥmān al-Adharmī al-Adnā,’ who is ʿAbd al-Raḥmān b. Yazīd b. al-Muhallab al-Azdī, one of the chiefs of this Azdī clan. He was killed at Mosul in 133 AH.” This remark requires reconsideration, for the shaykh explained that Abū ʿAbd al-Raḥmān made this argument before al-Wāthiq when he debated Ibn Abī Duʿād; Ibn Abī Duʿād was born in 160 AH (as noted above), which shows that the person in question is not the one identified by the editor but rather the one established and described here. (1) All known manuscripts read “al-Adnā,” but the correct reading appears to be as given above. See: • Tārīkh Baghdād, 10/79. • Manāqib al-Imām Aḥmad by Ibn al-Jawzī, pp. 433–434. The nisba al-Azdānī derives from Udhna, a well-known town on the Syrian coast near Tarsus. See Al-Lubāb by Ibn al-Athīr 1/39. Ibn al-Jawzī relates in Manāqib al-Imām Aḥmad (pp. 433–434) the story of al-Adharmī’s encounter with Ibn Abī Duʿād and their disputation before al-Wāthiq. Ṣāliḥ b. ʿAlī b. Yaʿqūb al-Hashimī said: “I had maintained that the Qurʾān is created from the time of al-Wāthiq until Aḥmad b. Abī Duʿād, an elder from the people of Udhna in Syria, was sent to us. They brought the shaykh before al-Wāthiq in chains…” (2) He is al-Muhtadī bi-Allah Abū ʿAbdallāh Muḥammad b. al-Wāthiq b. al-Muʿtaṣim, one of the Abbasid caliphs. He was proclaimed caliph in 255 AH after the deposition of al-Muʿtazz, born in 222 AH and died in 256 AH. See: • Al-Kāmil by Ibn al-Athīr, 7/198–235. • Al-Bidāya wa-al-Nihāya by Ibn Kathīr, 11/20–28. • Al-Aʿlām by al-Zarkalī, 7/351–352.