Philosophical Psychology in Islamic Kalam in the Sixth and Seventh Hijri Centuries

The philosophical psychology of Muslim thinkers in the sixth and seventh centuries (AH) was influenced by Ibn Sina’s discussions of the soul. However, the difference was that Ibn Sina tried to demonstrate only the immateriality of the rational faculty. Nevertheless, after him, some thinkers focused on interpreting the immateriality of all levels of perception in the soul. Following Ibn Sina, Nasir al-Din Tusi considered the rational soul to be a substance separate from matter as well as a simple and spiritually originated entity which, in the course of its development enjoys an administrative relation to the body. Based on the belief in the concomitance of immateriality and immortality, Tusi demonstrated the immateriality of all the perceptive levels and subsistence of rational souls by employing solid intellectual arguments. He also believes that the soul and body affect each other, and neither the corruption of the body nor any other factor can cause the annihilation of the simple and immaterial rational soul. However, Fakhr al-Din Razi has a dual theory of the nature of the soul and its relationship with the body. Sometimes, like Islamic philosophers, he views the soul as an immaterial substance drawing on Ibn Sina’s arguments in order to demonstrate its immateriality and, sometimes, like most Islamic mutakallimun, he introduces the soul as a subtle entity which dominates the body in the light of the power of Almighty God.