Distinction between Existence and Essence in Avicenna’s Ontology and Its Influence on Christian Philosophical Theology with a Focus on Aquinas’ Views

Document Type : Research Paper


1 Associate Professor, Shahid Beheshti University, Tehran, Iran

2 Assistant Professor, Shahid Beheshti University, Tehran, Iran.



Avicenna is an influential philosopher whose contributions in ontology led to the transformation of Greek philosophy into philosophical theology in the Middle Ages. He distinguished between existence and essence, divided beings into necessary and contingent beings, and believed in the objectivity of existence. This article discusses Avicenna’s innovations in philosophical ontology and its influence on Christian ontology and theology, especially on Aquinas’ thought. The article focuses on the distinction between existence and essence and its implications in Avicenna’s philosophy and studies its influence on Aquinas’ theology. It will show that although Aquinas, especially in his De Ente et Essentia, is influenced by Avicenna’s ontology, his understanding of Avicenna’s views are sometimes inaccurate, and this has led him to disagree with Avicenna in some cases.


Aquinas, Thomas. 1952. Summa Theologiae (STh). Translated by Fathers of the English Dominican Province. Revised by Daniel J. Sullivan. Chicago: The University of Chicago Press. 
Aquinas, Thomas. 1975. Summa Contra Gentiles (SCG). Translated by James. F. Anderson. London: University of Notre Dame Press.
Aquinas, Thomas. 1983. Essence and Existence. Translated by Armand Maurer. Toronto: The Pontifical Institute of Medieval Studies. 
Aquinas, Thomas. 1996. Commentary on Aristotle’s Metaphysics. Translated by John. P. Rowan. Notre Dame, Indiana.
Aristotle. Metaphysica. 1966. Translated into English by W. D. Ross. 2nd edition. Oxford: The Clarendon Press.
Averroes. 1986. Commentary on Aristotle’s Metaphysics. Translated by Charles F. Genequand. Leiden: Brill.
Burrell, D. 1993. “Aquinas and Islamic and Jewish thinkers.” In The Cambridge Companion to Aquinas, edited by N. Kretzmann and E. Stump, 60-84. Cambridge: Cambridge University Press.
Copleston, Frederick. 1950.A History of Philosophy. London: Search Press.
Davies, Brain. 2002. Thomas Aquinas. London and New York: Continuum.
Elders, Leo J. 1990. The Philosophical Theology of Thomas Aquinas. Leiden: Brill.
Elders, Leo J. 1993. The Metaphysics of Being of St. Thomas in Historical Perspective. Leiden: Brill.
Hasse, D. N. 2014. “Influence of Arabic and Islamic Philosophers on the Latin West.” In The Stanford Encyclopedia of Philosophy (Spring 2020 Edition), edited by Edward N. Zalta. URL = <https://plato.stanford.edu/archives/spr2020/entries/arabic-islamic-influence/>.
Ibn Rushd (Averroes). 1998. Talkhīṣ mā baʿd al-ṭabīʿa. Beirut: Muṣṭafā al-Bābī.
Ibn Sīnā (Avicenna). 1974.Al-Ishārāt wa l-tanbīhāt. Tehran-Qom: Nashr Balāghat.
Ibn Sīnā (Avicenna). 1984a. Al-Mabdaʾ wa l-maʿād. Tehran: Muʿassasa Muṭālaʿāt Islāmī.
Ibn Sīnā (Avicenna). 1984b. Al-Najāt min al-gharaq fī baḥr al-ḍalālāt. Intishārāt Dānishgāh Tehran.
Ibn Sīnā (Avicenna). 1992. Al-Mubāḥathāt. Qom: Intishārāt Bīdār.
Ibn Sīnā (Avicenna). 1997. Al-Ilāhīyyāt min kitāb al-Shifāʾ. Markaz Nashr.
Ibn Sīnā (Avicenna). 2000. Al-Taʿlīqāt. Qom: Markaz Intishārāt Daftar Tablīghāt Islāmī.
Ibn Sīnā (Avicenna). 2004. Dānishnāma-yi ʿAlāʾī. Hamadan: Anjuman Āthār va Mafākhir Irān.
Izutsu, Toshihiko. 2009. The Concept and Reality of Existence. Tokyo: Keio University.
Kenny, Anthony. 2002. Aquinas on Being: Oxford: Clarendon Press.
Kretzmann, Norman. 1944. Aquinas. Cambridge University Press.
Owens, Joseph.1958. “The Accidental and Essential Character of Being in the Doctrine of St. Thomas Aquinas.” Mediaeval studies 20: 1-40.
Walton, William M. 1950. “Being, Essence and Existence for Thomas Aquinas.” The Review of Metaphysics 3 (3): 339-95.
Wippel, John F. 1990. “The Latin Avicenna as a Source for Thomas Aquinas’s Metaphysics.” Freiburger Zeitschrift Für Philosophie Und Theologie 37 (1/2): 51-90.