• Andrew

Body and Soul

Updated: Apr 14, 2020

Many think humans are a combination of body and soul, but this idea has come under attack. Has modern neuroscience disproved the existence of the soul, or is the physical world an illusion generated by consciousness?

I believe that a human person is one thing that is both body and soul and that all human actions are simultaneously spiritual and physical.

Contemporary Extremes

Is there no space for the soul?

Skimming through a contemporary science periodical, you will likely discover at least one article arguing against a traditional belief. The human soul is one of these ideas most frequently attacked. The arguments typically go something like this, "people believed that the soul did X, we now see that something happens in the brain when you do X. Therefore, the soul does not exist." (1) The line of thinking is, if you can discover the body doing something, then the soul isn't.

"There is nothing left for the soul to do." David K. Johnson. "Does the Soul Exist?" Think, V.12, I.35

Is the body is an illusion?

Based on other observations, some argue that the material world is not real, and the only thing that exists is consciousness. The evidence used to justify this position is the realization that material things are not what we assume. For example, some calculate that about 5% of the universe's matter and energy are the sort that we experience with our senses, the rest is called "dark matter" or "dark energy." Additionally, the evidence that smaller parts make up physical objects, and even smaller pieces constitute those. The total mass of these smaller particles accounts for a fraction of the space occupied by the object. Thus, the things we experience as concrete are more nothing than they are something. Based on these and other observations, there is no absolute foundation for the objects of experience, and our perceptions are not reliable. They conclude that the things we experience are not real, but since I am conscious of thinking, my consciousness is real.

"Without consciousness, nothing can be proven to exist. Simply by being conscious, you participate in the mind-made world and help create it every day. The beauty of this understanding is that if creation springs from consciousness, we can reshape reality from its source." Deepak Chopra, M.D., Metahuman, 17-18

Are either of these conflicting views true? If we hold a traditional belief that the physical world and the soul are real, how can we justify this position? Using empirical evidence, one line of thought denies the soul (some even reject the idea of mind). The other uses the evidence to discredit the material world. Substantive observations base both of these arguments, but the conclusions they draw from the evidence are overreaching. Both of these views commit a logical fallacy called Affirming the Consequent. You can detect this fallacy by structuring a thought as an "if, then" statement. If you demonstrate what is before the "then," you have proven what is after the "then." If you only confirm what comes after the "then," what is before it is possible but not verified. Let's break them down. We could state the first argument, "if the soul does not exist, then we will see activity in the brain every time we think." The evidence demonstrates that the brain is always involved in thought. This argument does not disprove the existence of the soul. It only shows that the soul may not exist. The second argument is, "if the world outside of consciousness is not there, then our experiences of the world will be inaccurate." The evidence put forward demonstrates that our experiences are not reliable due to their limited nature, our biases, or assumptions. It does not follow that consciousness constructs the world. It leaves this as a possibility, and, based on this, naive realism is not cogent. We can still reasonably believe that the soul and the world exist. In addition to the logical fallacy, both views make their case against something different than what many classic thinkers believed. They are arguing against a view of reality called "substance dualism."

Substance Dualism

Substance Dualism is the opinion that a human is two things put together. One of these items is spiritual, a soul. The other part is physical, a body. Often this conception includes assigning some portion of human experience to the soul; where the body stops, the soul begins.

One of the most famous Substance Dualists is René Descartes. In his book Discourse on Method, he establishes that he can doubt every sense experience. He finds a stable foundation for reality in the indubitable principle, "I think; therefore, I am." (2) Later he observes that he is his soul, what he calls the "thinking thing," and the body is an "extended thing" that takes up space. In this vision, some parts experiences are accounted for by the soul and others by the body.

I think many people default to this understanding. If we believe in a body and soul, we may feel that our true self is the spiritual part "inside." Descartes uses the image of a captain and a ship. The soul is the captain, and the body is the boat the soul controls. My sophomoric graphic illustrates this idea.

In this model, up to a certain point, the body accounts for human experience. Then the soul picks up where the body leaves off. Moving is a physical activity, and thinking is a spiritual activity. The body and soul relate to each other as cause and effect. The spiritual mind initiates an action that the body carries out.

The two contemporary extremes that we started with are both stuck in this way of thinking. The first proclaims, "there is nothing left for the soul to do." The human body accounts for all human experience. The second starts with affirming, "I think therefore I am," but then denies the rest of reality. A full philosophical critique of substance dualism is beyond the scope of this article. I want to point out another option.


The word "Hylomorphism" comes from two Greek words, "Hyle" means matter, and "Morphe" means form. The form of something is its essence or, most simply, what makes it what it is. The matter is in-formed by the essential form. These two aspects of each thing constitute one substance or nature.

The form explains the enduring identity of things in a world of continuous change. For example, I could replace a part of a table today, and another part of the table tomorrow. Then I could continue to replace one part of the table daily until the same table is put together by all new parts. Is it still the same table? The table's identity endures even with the accumulation of changes. Similarly, the body slowly replaces every one of its cells: cells die through a process called apoptosis, and new cells are born through cell division. On average, every seven to ten years, my body has almost all new cells, yet, I am still me. (3) I am more than the sum of my parts. I am my body animated by my form, the soul.

When the church talks about the soul, it does not intend us to imagine a ghost trapped in the body. The church holds that the soul is the form of the body:

"The unity of soul and body is so profound that one has to consider the soul to be the "form" of the body: [(4)] i.e., it is because of its spiritual soul that the body made of matter becomes a living, human body; spirit and matter, in man, are not two natures united, but rather their union forms a single nature." Catechism of the Catholic Church 365

The soul makes the body a living body. A corpse is simply a human body without a soul. The "single nature" that the body and soul constitute is commonly called a person. In this world view, I am more than just my body, and I am more than my mind. I am a person that is a body and soul from which consciousness emerges.

Hylomorphism is not without its own philosophical and theological difficulties, but it provides an understanding of the human person that can accommodate contemporary scientific discoveries and traditional philosophy and theology.


The whole soul is in union with every part of the body. (5) I think that every human action would include a physical and spiritual correlate. The body is involved in a manner measurable with scientific instrumentation, and the soul is engaged in a way that is demonstratable with a philosophical or theological proof. For example, human actions have a moral dimension.

From this perspective, we expect that the brain would be involved in every element of consciousness. Still, it is not a demonstration that the soul is not simultaneously engaged in the process. A reductive exploration of something will not yield evidence of its existence. Everything is a composition of form and matter, and an engagement with the whole, not the parts, yields knowledge of the form.

This perspective invites us to engage the world with wonder. Wonder is an exploration with open-minded trust. In this posture, we can discover the complexity of the world with the scientific method. At the same time, we can contemplate the unity of things and questions beyond the scientific method. Then we can proclaim with the psalmist.

"I praise you, because I am wonderfully made; wonderful are your works!" Psalm 139: 14


Aquinas 101 - Form and Matter

Aquinas 101 - Body and Soul

Physically Spiritual - The Story of a Body

Further Reading

Catechism of the Catholic Church, Part 1, Section 2, Chapter 1, Article 1

St. Thomas Aquinas, Summa Theologiae, Part I, Question 76

Aristotle, De Anima

Fr. Norris Clarke, S.J. The One and the Many. Notre Dame, 2001.


(1) "The Astonishing Hypothesis is that "You," your joys and your sorrows, your memories and your ambitions, your sense of identity and free will, are in fact no more than the behavior of a vast assembly of nerve cells and their associated molecules." Francis Crick, The Astonishing Hypothesis.

(2) René Descartes, Discourse on Method, Part IV.

(3) There are a few notable exceptions to this estimate on cellular regeneration. Fat cells stay with us around 25 years, and some believe that some neurons, parts of the heart, and the lenses of our eyes remain with us our entire life.

(4) "Moreover, with the approval of the said council, we reject as erroneous and contrary to the truth of the catholic faith every doctrine or proposition rashly asserting that the substance of the rational or intellectual soul is not of itself and essentially the form of the human body, or casting doubt on this matter. In order that all may know the truth of the faith in its purity and all error may be excluded, we define that anyone who presumes henceforth to assert defend or hold stubbornly that the rational or intellectual soul is not the form of the human body of itself and essentially, is to be considered a heretic." Council of Vienne (1312)

(5) St. Thomas Aquinas, Summa Theologiae, Part I, Question 76, Article 8.

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