Originally introduced by Plato and Aristotle, Moderation Theory in Ethics is the most prevalent theory of ethics among Islamic scholars. Moderation Theory suggests that every virtue or excellence of character lies in the mean between two vices: excess or defect. Every ethical virtue comes from moderation in actions or emotions and every ethical vice comes from excess or defect. This paper suggests that while Islamic scholars have been influenced by this doctrine, they have also developed and re-conceptualized it in innovative ways. Kindī, Miskawayh, Avicenna, Rāghib Isfahānī, Nasīr al-Dīn Ṭusī, and others are among the Islamic contributors to the subject. Some of their innovations in this theory are as follows: bringing together Aristotle's doctrine of the mean with Plato's psychology (by Kindī), dividing virtues into four higher genuses, dividing vices into eight higher genuses, setting various kinds of vices and virtues under these higher genuses (by Miskawayh), adding the vice qualitative criteria to Aristotle's vice quantitative criteria (excess and defect) (by Ṭusī), dividing various conceptualizations of justice (by Avicenna), adding religious and mystical virtues into the existing list of virtues (by Rāghib Isfahānī), and proposing a comprehensive model for curing diseases of the soul. This paper seeks to establish the main contributions of these Muslim scholars to Moderation Theory and elaborate on this theory’s evolution within the Islamic world.
