By: Brian G. Chilton, Ph.D., M.Div. | October 29, 2023
As I began reading through Thomas Aquinas’s Summa Theologica, I was made aware of a recent debate among Thomists concerning Aquinas’s belief in the soul. Was Aquinas a dualist or a monist? Dualists believe in the duality of man in that each person has two parts of their being—a material body and an immaterial soul. In contrast, monists contend that a person only has a body with no immaterial self. Thus, dualists often believe that the soul of a person survives death and joins God in an immaterial state after the body dies. Monists believe that there is no immaterial state after death. Monistic believers contend that the believer’s hope is found in the resurrection, not in an ethereal heaven.
Was Aquinas a dualist? Some have maintained that Aquinas was a monist due to the connectedness that Aquinas held between body and soul.[1] On the flip side, Thomistic scholars such as Edward Feser and Howard Robinson contend that Thomas was indeed dualistic in his understanding of the soul and body, terming his form of belief a “hylemorphic dualism.”[2] In this summary, let’s look at the teachings of Thomas Aquinas on a person’s body and soul and discover the answer for ourselves.
The Nature of the Soul’s Distinctiveness from the Body
Aquinas’s view of the body and soul is a bit distinct from other forms of dualism, including the more famed Cartesian dualism.[3] Aquinas does believe that the soul and body are distinct, however, he holds some nuances with their distinctiveness as will be shown in the next point.
However, it cannot be denied that Aquinas did believe that the soul and body were distinct in their essence. Aquinas maintains that “we must assert that the intellect which is the principle of intellectual operation is the form of the human body.”[4] This gets into some deeper level philosophy at this juncture. In Platonic thought, forms are the immaterial blueprint for each material object. For Aquinas, the soul is an immaterial substance that is comparable to the Platonic form.
Aquinas clarifies his position in his earlier question when writing that the soul is the “first principle of life, is not a body, but the act of a body; thus heat, which is the principle of calefaction, is not a body, but an act of a body.”[5] An “act” is being in this case. The soul is the “principle of intellectual operation”[6] and is both “incorporeal and subsistent.”[7]
By “incorporeal,” Aquinas means to say that the soul is immaterial and spiritual. By “subsistent,” Aquinas teaches that the soul exists independently and apart from the body.[8] As such, the existence of the body depends on the soul, but the existence of the soul does not necessarily depend on the body. In my understanding of Aquinas, it is quite clear that he draws a distinction between the soul and the body. Therefore, Aquinas is most assuredly a dualist.
The Nature of the Soul’s Driving Force
While Aquinas is a dualist in every sense of the term, he is responsible with his dualism. He does not take the road of the Gnostic to argue that the body and material world are somehow evil by nature. Like Augustine and the classic theologians before him, St. Thomas asserts the redemption that will one day come to the material world. For St. Thomas, each human person is a merged being of both body and soul. One should not discard the importance of the human body for the soul alone. Rather, the body and soul are united within a composite being.
Aquinas’s concept comes from Aristotle and is called hylemorphism. Hylemorphism is a combination word that describes the concept by blending two Greek terms: hyle meaning matter, and morphes meaning form. Like Aristotle before him, Aquinas believed that every being had a form (immaterial substance) and a body (material substance). From the very outside, the line of thinking is dualistic in nature. However, Aquinas draws a masterful distinction between the human soul from other forms, as will be seen in the final point. For Aquinas, the soul is what gives the body shape and existence. It is through the soul that the world is understood,[9] even though the body gives information for the soul/mind to process.[10] The soul is a power that moves the body and can, therefore, exist separately from the body.[11] But Aquinas maintains the unity of body and soul, teaching that “since the soul is united to the body as its form, it must necessarily be in the whole body, and in each part thereof.”[12]
The late Norman Geisler summarizes the concept of Aquinas’s hylemorphic dualism quite well in his book Thomas Aquinas: An Evangelical Appraisal. He writes the following:[13]
The human soul is the formal cause while the body is the material cause of a human being. God, of course, is the efficient cause. Parents are only the instrumental cause of the body. The final cause (purpose) is to glorify God, who created us. Adam was directly created by God at the beginning, and God directly creates each new soul in the womb of its mother.[14]
The Nature of the Soul’s Incorruptibility
While the soul is united to the body, can it survive death? Does it continue to live on once the body has passed? Working in hospice care, I have seen firsthand evidence of the survival of the soul, to the point that it is beyond a shadow of a doubt that the afterlife is real, at least in a spiritual state. Aquinas would concur. In fact, Aquinas devotes Question 89 in the first volume of the Summa Theologica to answering specific questions about how the soul knows and learns outside the body.
Aquinas not only argues that the soul exists outside the body, but he also asserts the incorruptibility, or immortality, of the human soul. St. Thomas states that matter is corrupted (i.e., dies) when the form (i.e., soul) is separated from it. But he goes on to say that “it is impossible for a form (i.e., soul) to be separated from itself; and therefore it is impossible for a subsistent form to cease to exist.”[15] Therefore, the soul definitively survives death in St. Thomas’s theology. Not only that, but it is also impossible for the soul to cease to exist after God creates it as it then becomes a subsistent and incorruptible form.[16]
Conclusion
To say the least, my study of the Summa Theologica has been theologically enriching thus far, and it only gets better the further I read. Having heard the different opinions of Thomistic thought on the nature of the human soul, I was startled to find how dualistic St. Thomas was in his theological perspectives. When we allow a person to speak for oneself, we are often able to grasp what the person is trying to communicate. As such, St. Thomas’s dualism is quite intriguing as he not only presents the immaterial and eternal nature of humanity in the human soul, but he also shows the unity that flows from the soul to the body. This series may very well return to the dualism of Thomas Aquinas as he has much more to say about human consciousness.
About the Author
Brian G. Chilton is the founder of Bellator Christi Ministries and the co-host of the Bellator Christi Podcast. Dr. Chilton earned a Ph.D. in the Theology and Apologetics at Liberty University (with high distinction), a M.Div. in Theology from Liberty University (with high distinction); his B.S. in Religious Studies and Philosophy from Gardner-Webb University (with honors); earned a Certificate in Christian Apologetics from Biola University, and completed Unit 1 of Clinical Pastoral Education at Wake Forest University’s School of Medicine. Dr. Chilton is a member of the Evangelical Theological Society and the Evangelical Philosophical Society. In his spare time, he enjoys reading, working out in his home gym, and watching football. He has served in pastoral ministry for over 20 years and serves as a clinical chaplain.
https://www.amazon.com/Laymans-Manual-Christian-Apologetics-Essentials/dp/1532697104
https://www.amazon.com/Conversations-about-Heaven-Difficult-Questions/dp/1666762687
Notes
[1] Alfred Freddoso, unlike Edward Feser and Howard Robinson, claims his uneasiness in understanding Aquinas’s view as a “hylemorphic dualism,” stating that “it is precisely the unity of the human being that St. Thomas wants to emphasize over against Plato’s position, which (as he interprets it) posits many substantial forms in the human composite.” Alfred J. Freddoso, “Oh My Soul, There’s Animals and Animals: Some Thomistic Reflections on Contemporary Philosophy of Mind,” The University of Notre Dame, South Bend, IN (October 5, 2012), footnote 5. In all fairness, Freddoso acknowledges Aquinas’s acceptance of the immaterial person later in the paper.
[2] See Edward Feser, The Last Superstition: A Refutation of the New Atheism (South Bend, IN: St. Augustine’s Press, 2010), and Howard Robinson, Real Essentialism (New York, NY: Routledge, 2007).
[3] Taken from the concepts of Rene Descartes.
[4] Thomas Aquinas, Summa Theologica 1.q76.a1., Fathers of the English Dominican Province, trans (London, Burns Oates & Washbourne, 1920).
[5] Aquinas, ST 1.q75.a1.
[6] Aquinas, ST 1.q75.a2.
[7] Ibid.
[8] “Therefore the intellectual principle which we call the mind or the intellect has an operation per se apart from the body.” Aquinas, ST q.75.a2.
[9] Aquinas, ST 1.q75.a2.rep.2.
[10] Aquinas, ST 1.q75.a2.rep3.
[11] Aquinas, ST q.75.a1.rep2.
[12] Aquinas, ST q76.a8.
[13] Many thanks to my good friend Dr. Thomas J. Gentry for pointing me to this gem from Norman Geisler.
[14] Norman L. Geisler, Thomas Aquinas: An Evangelical Appraisal (Eugene, OR: Wipf and Stock Publishers, 2003), 41.
[15] Aquinas, ST 1.q75.a6.
[16] For Aquinas, the annihilationist perspective would be absurd as he holds to the immortality of the human soul.
