IKHWĀN AL-ṢAFĀʾ (Brethren of Purity) is a pseudonym assumed by the authors of a well-known encyclopedia of the philosophical sciences who described themselves as a group of fellow-seekers after truth. Members of a religio-political movement, they deliberately concealed their identity so that their treatises, entitled Rasāʾil Ikhwān al-Ṣafāʾ (Epistles of the Brethren of Purity), would gain wider circulation and would appeal to a broad cross-section of society.

Authorship and Dating

Over the centuries, the authorship of the Epistles has been ascribed to the Muʿtazilah, to the Ṣūfīs, to Imam Jaʿfar al-Ṣādiq, and to the great astronomer and mathematician al-Majrīṭī. The assertion of Abū Ḥayyān al-Tawḥīdī (d. 1023) that the treatises were composed by a group of learned men in Basra...