Jerek B. Petrous, DDS, MS

As healthcare professionals, we know our patients have brains, we know they have hearts. We know these exist because we can see them and study them. They are physical, they are material. But is there a part of us that is immaterial, or is this just a lie we’ve bought into? If so, how can we possibly know it?

As Christians, we believe in the Bible which teaches us that the world around us is dualistic, meaning there are two coexistent realms and realities, the physical realm, and the immaterial or spiritual realm. If this is not true, then God cannot exist, our souls are just a figment of our imagination and heaven is just wishful thinking.

So how can we begin to prove the existence of something we cannot see? This question, although a valid one, is based on the faulty, yet popular notion that science is our only source of truth (scientism). But clearly, this is false. Other equally valid examples of discovering truth exist completely apart from science, including basic arithmetic, philosophy, the laws of logic, history or the reality that rape is objectively wrong, for example. Neither of these can be proven or disproven by the scientific method, but we all know they are true.

In assessing whether the soul actually exists or not, philosophy, logic and history provide us with ample evidence.

Evidence for the Soul #1: The Mind is Not the Brain
To demonstrate this, we must use a fundamental law of logic, called the law of identity. It simply states that something on one side of the equal sign is identical to something on the other side if they have the exact same qualities and properties. If you can think of one thing that is true of the mind that is not true of the brain, then logically, they are not the same thing. A person who believes the physical world is all there is (naturalism) would argue the following:

The brain/body (physical) = the mind/soul (mental)

Physical properties (the left side of the equation) can be publically known and seen using our five senses, such as when I look at the table in front of me. The table is physical and can be accessed by anyone near it. Mental properties (the right side of the equation) are only privately known, such as how the table makes me feel or where I’m going to put this table. Nobody can access my thoughts about the table, outside of me telling them because I am the only one who has access to these. It is not possible, for example, to look at an MRI or a PET scan and view my thoughts about something. It is not possible for anybody to have first person access to my thoughts. Your thoughts occur in your mind and these are correlated with physical states occurring in your brain—but they are not the same. Therefore, the physical brain and the immaterial mind are not identical, but separate.

Evidence for the Soul #2: Free Will
The only way we could possibly have free will is if we have an immaterial mind separate from our physical self. However, if all we are is nothing but greatly evolved physical organisms, then all our behaviors are determined by how the neurons in our brains react to the environment around us, and any semblance of free will is simply an illusion. Every move and decision would be made based on prior causal factors.

Matter, chemistry and electrical impulses cannot exercise free agency. It is hard to deny, however, that we humans have significant freedom and moral responsibility and therefore true free will. We know from experience that we are free to do what we choose when we reflect on our choices utilizing our higher order thinking. The fact is, either we are determined and free will is an illusion, or we have the genuine ability to make decisions as free creatures, and if the latter is true, we have more powerful evidence for the soul.

Evidence for the Soul #3: Jesus Makes This Clear
Lastly and most importantly, Jesus taught that there is a soul, and this is highly significant, especially in light of the powerful historical evidence we have today that He actually rose from the dead.

“And do not fear those who kill the body but cannot kill the soul. Rather fear him who can destroy both soul and body in hell” (Matthew 10:28, ESV).

Although we’ve only scratched the surface, as we have seen, we are more than bags of chemicals, we are embodied souls made in the image of God. And this is not wishful thinking, it is rooted in reality.