This article aims to investigate the possibility of the soul’s motion across its various existential realms, based on the Islamic and Christian philosophical foundations. To this end, the viewpoints of three major thinkers — Ibn Sīnā and Mullā Ṣadrā from the Islamic tradition, and Thomas Aquinas from the Christian tradition — are analyzed, drawing on their most significant works and using a descriptive-analytical methodology. Ibn Sīnā limits the soul’s motion to its accidents, holding that the soul’s substance is static and lacks essential motion. In contrast, Mullā Ṣadrā, by introducing the primacy of existence, the gradation of existence, and trans-substantial motion, affirms motion in the substance of the soul as long as it is connected to the material body. Although both philosophers initially reject motion in the immaterial or purely intellectual soul because it lacks matter, other philosophical principles for the motion of the immaterial soul can be considered. They include Ibn Sīnā’s development of the meaning of potency and matter, and Mullā Ṣadrā’s principle of existential intensification and the unity of the intellect, the intelligizer, and the intelligible. In the Christian tradition, Thomas Aquinas generally rejects the soul’s motion by affirming its simplicity. Nevertheless, he paves the way for affirming motion in the soul by proposing a new kind of definition for passivity/receptivity and potency that does not necessitate matter but is related to existential imperfection. By distinguishing between the intellectual grade of the soul, which he considers to possess potentiality, and the pure intellect, which is pure act, he opens a new avenue for proving the soul’s motion even after its separation from the body. Consequently, despite considerable commonalities in their philosophical foundations, these three philosophers offer different analyses of the soul’s motion by relying on specific distinctions, which, in the case of Mullā Ṣadrā and Thomas Aquinas, show points of convergence.
Keywords: Substantial Motion, Intellectual Motion, Potency and Act, Existential Perfection.
For citation
Roodgar N. The Motion of the Soul According to Avicenna, Mulla Sadra, and Thomas Aquinas. Christianity in the Middle East, 2025, vol. 9, no. 5, pp. 67–87. https://doi.org/10.65324/cme009