American philosopher and cognitive scientist Daniel C. Dennett said in an interview with the online web-series The Science Studio that the soul is “made of neurons [and] tiny robots” and that an “eternal, immortal, immaterial soul is just a metaphysical rug under which you sweep your embarrassment for not having any explanation.”
If Dennett is right, and man’s soul does not continue to exist after death due to its materiality, then one of the central tenets of the Christian faith would be undermined—namely, heaven. It would be futile to speak of an everlasting existence in heaven if there were no everlasting souls to experience it.
The immortality of the human soul is a necessary prerequisite for anything like heaven. This is why it’s called a preamble of faith. So, its truth is definitely worth defending. But how do we go about doing that?
There are two questions that we have to answer in order to find out if the soul is immortal. The first is, “Can the human soul survive bodily death?” The second is, “Is the human soul, once separated from the body, naturally subject to destruction?”
It’s one thing to show that man’s soul can survive bodily death. But it’s another to show that the human soul is naturally immortal and thus not subject to any type of natural destruction. Just because the destruction of the body doesn’t cause the destruction of the soul, it doesn’t mean the soul can’t be destroyed in some other way. It’s necessary to prove that the human soul is immortal by nature and thus not subject to any form of natural destruction.
Let’s consider the first question: “Can the human soul survive bodily death?”
A survivor’s guide
In order to make it easy to follow, I’d like to set up the argument with a syllogism. This allows us to see the flow of the argument from a bird’s-eye view without getting into the weeds of the premises. Once we have the argument down, we can then consider the justification for each of the premises.
Here’s the syllogism.
P1: If the soul has some activity that is, of itself, exercised apart from the body, then the soul would be able to exist without the body.
P2: The soul has some activity that is, of itself, exercised apart from the body.
C: Therefore, the soul is able to exist without the body.
Now that we have the argument down, let’s consider each of the premises, starting with premise one.
Action follows being
Our justification of premise 1 follows from a very important principle in philosophy: agere sequitur esse (“action follows being”). What this means is that a thing is going to act only insofar as its nature determines it to act.
For example, a bird can fly only because its nature, bird nature, allows it to do so. A fish can breathe underwater and will die out of water because it belongs to its nature to operate in such a way. A stone cannot exhibit effects of nutrition, growth, and reproduction, because its nature doesn’t allow it. Such effects go beyond the nature of stone.
Based on our experience, therefore, we can say that the nature of a thing determines a thing’s way of existing—its way of life and action. And it follows from this that knowledge of a thing’s activities can give knowledge of a thing’s nature. In other words, if it walks like a duck and quacks like a duck, it’s a duck.
Not only do we know from experience that action follows being, but it’s metaphysically necessary. Consider the stone, for example. If a stone could exhibit effects of nutrition, growth, and reproduction, and the potential for such activities didn’t belong to its nature, then we would have something coming from sheer nothingness. But from nothing only nothing comes, as Parmenides said so long ago. Therefore, a stone can’t exhibit vegetative functions without having a vegetative nature lest we deny the principle of sufficient reason.
So, it’s necessary that action follow being. As such, if our soul can operate in some way independent of matter, then its nature is something that is not dependent on matter in its existence. Therefore, when separated from the body, it could continue to exist.
The philosopher Michael Augros gives a great example to illustrate this idea in his book The Immortal You: How Human Nature Is More Than Science Can Say. The workaholic, whose life consists only in work, will have a hard time living the life of retirement.
Why? He doesn’t have a life beyond work. The person who has cultivated a life outside work, on the contrary, will have an easier time enjoying life in retirement. Because he has a life outside work, when the life of work ceases, he will continue to have a life.
The existence of the soul in relation to the body is kind of like that. If the soul has a way of existing that is not entirely dependent on the body, which is just another way of saying that it has a way of operating without the body (since everything operates inasmuch as it exists), then the soul can exist without the body.
In other words, if the soul does more than just inform the body and make it a living and sentient thing, then it could continue to exist when there is no more body to make living and sentient.
So, premise 1 is validated: If the soul has some activity that is, of itself, exercised apart from the body, then the soul would be able to exist without the body.
Action within matter
Now we come to premise 2: the soul has some activity that is, of itself, exercised apart from the body. There are several arguments that we could give to justify this premise, but for brevity’s sake I’m going to offer only one, and that is an argument from our knowledge of universals. There are two steps to the argument.
The first step is to see how human sensory powers are constrained by the conditions of matter because they are exercised through a material medium, namely, bodily organs.
Let’s take the power of sight, which is exercised through the bodily organ of the eye. When I see Socrates, I necessarily see this man, confined to this time and in this space. I see Socrates on the right of this tree and on the left of that tree. I notice that Socrates is taller than that plant growing at his feet.
When I see a triangle drawn on a piece of paper, I necessarily see this triangle, confined to this time and this piece of paper located in this place. I see it in spatial relation to that bigger triangle drawn on another piece of paper to its right. I see both pieces of paper on which the triangles are drawn as resting on top of the desk that’s keeping the papers off the ground.
Notice that what I’m knowing through my power of sight is constrained by the conditions of matter: singularity (this man, this plant, this tree, this triangle), spatial relations (Socrates on the right of this tree and the left of that tree, the point at the top of the triangle is above the bottom line, the pen is on the right of the triangle), and quantitative dimensions (Socrates is taller than the plant, triangle A is bigger than triangle B).
The reason for my sensing these particularities, spatial relations, and quantitative dimensions is because my power of sight is being exercised through the material medium of the eye. Those things that I see are making an impression upon my sensory organ, and since my sensory organ is material, and thus constrained by the conditions of matter, my power of sight is necessarily constrained by the conditions of matter.
Augros uses a great example to illustrate this in his aforementioned book. Imagine that you’re watching a movie on a movie screen in the theater. Any image that is cast upon the screen is going to have diverse parts and be spread out in space because the screen itself has diverse parts and is spread out in space.
Our eye, and even our brain, is like the movie screen. Whatever info comes in through this organ is necessarily going to be under the conditions of matter because the organ itself is material. Thus, I’m only going to see this man. I’m going to perceive this man being here and not there. I’m going to perceive this man being taller than the plant near his foot. I’m going to perceive the color brown located here, in this man’s hair.
Moreover, because my eye has parts and is extended in space, like the movie screen, the spatial relations (Socrates here and not there, the plant below Socrates, etc.) that I see in my visual field are a consequence of those relations impressing upon different portions of my eye and even in my brain.
Another analogy is the use of rose-colored glasses. The medium of the glasses would affect the way I see things, confining my power of sight to seeing only things with a shade of red. Similarly, the material medium of the eye affects the way I see things, confining my power of sight only to things that are constrained by the conditions of matter.
From this we can conclude that because my power of sight is exercised through the material medium of the eye, my power of sight necessarily always attains its objects under material conditions: particularity, spatial relations, and quantitative dimensions.
So, if the intellect understood concepts such as man and triangularity through a material medium, then the act of understanding, like the power of sight through the eye, would attain its objects under the conditions of matter. I would understand only this triangle or that triangle restricted to this time and this place. I wouldn’t understand triangularity itself, which applies to all triangles at all times and in all places. I would understand only this man or that man restricted to this time and this place. I wouldn’t understand the concept of man itself, which, once again, applies to all men at all times and in all places.
Moreover, my thought of man would be spatially related to my thought of triangularity, either to the left or the right of each other. My thought of man would be either bigger or smaller than my thought of triangularity.
But is this how we understand these sorts of concepts? No!
Action beyond matter
This leads us to the second step in our argument: human beings have a capacity to know the “form” or “essence” of something in a universal way, stripped of all material conditions. In other words, the human intellect is able to attain its object in a way that transcends the conditions of matter.
Consider, once again, a triangle. Whether we draw a red triangle, a blue triangle, or a green triangle, we know that all three are triangles. Even if we draw a triangle with chalk on the chalkboard, or one in the sand, or one with ink on a paper, we still know that all three are triangles. Even the size of the triangle doesn’t matter. We could draw a big one or a small one and it still would be a triangle, and we would know it as such.
Notice that in these examples we’re able to know the essence, the nature, or the form of triangularity independent of the material conditions that make up each of the triangles—their size, color, location, and the stuff each one is made of.
Moreover, we’re able to know what a triangle is independent of each particular triangle. Our understanding of triangularity is not restricted to this triangle or that triangle but transcends all particular triangles. This means our knowledge of the nature of a triangle is universal: it can be applied to all triangles, anywhere and at any time. As such, our knowledge of triangularity is not encompassed in matter. It breaks the boundaries of matter entirely.
We can also use the example of our knowledge of what a human being is. Suppose we have Socrates, Aristotle, and Plato standing before us, each of whom are different in height, weight, color, and spatial location. And as we inquire about what all three of these beings are, we rightfully conclude that each is a human being.
But notice that our knowledge of what a human being is is not restricted to our knowledge of Socrates, Aristotle, or Plato. Our understanding of the essence of a human being transcends them all, breaking the boundaries of the material conditions that individualize each man and the particularity that necessarily belongs to each of the men.
Even our thoughts about “what a man is” and “what a triangle is” when taken together are not spatially related to each other. No sense can be made of our thought about man being to the right of our thought about triangularity, or our thought about man being bigger than/taking up more space than our thought about triangularity. This is an indication, once again, that our act of knowing these ideas is not under the conditions of matter.
So, we could sum up our argument for premise two like this:
P1: If the intellect acted upon its object of universal ideas through a material medium, like the brain, then it would know its object under the conditions of matter.
P2: But the intellect doesn’t know its object under the conditions of matter.
C: Therefore, the intellect does not act upon its object of universal ideas through a material medium.
Therefore, the intellect’s activity, in itself, is independent of matter, and thus premise 2 of our overall argument is validated: the soul has some activity that is, of itself, exercised apart from the body.
Since both premises of our overall argument are proven to be true, the conclusion necessarily follows: the soul is able to exist without the body.
Natural destruction
But this doesn’t mean the soul is indestructible. Sure, the destruction of the body doesn’t destroy the soul, but perhaps there is some other way that the soul could go out of existence.
For example, whatever is made up of parts can break apart. Can the soul break apart? Or, perhaps the soul can go out of existence like a tree goes out of existence when the matter loses its form as it’s being put through the wood chipper.
Let’s take a look at these alternative options and see if the soul fits the bill.
We know that the soul can’t be destroyed via breaking apart, because the soul is not made up of parts in the first place, being that it’s immaterial. We know this is true given its immaterial activity of intellectual understanding, as demonstrated above. We also know the soul is immaterial, because if it were material, or a body, then all bodies would be living things, since the soul is the principle of life in living things. But not all bodies are living things, as can be empirically verified by looking at the rocks outside. Therefore, the soul is not material, or a body.
And if the soul is not material, then it can’t be made up of parts—it’s simple (non-composite). But if it’s not made up of parts, then it can’t go out of existence by breaking apart.
The soul also cannot be destroyed via being separated from its form. Every material thing is composed of what philosophers refer to as form and matter. For example, a tree is composed of a certain kind of matter—mostly wood—and a certain kind of form—the form of a woody vegetative organism that grows upward with a trunk that produces lateral branches above the ground.
Now, destruction comes when a thing loses its form and is replaced by another. A tree loses its form, for instance, and thus ceases to exist, when I cut it down and throw it into the wood chipper. The matter loses the form that was making it the kind of thing it was—namely, a tree—and takes on the form of wood chips. Therefore, if something can lose its form and be replaced by another form, then it can be destroyed.
But unlike the tree, which can lose its form due to its nature as a matter-form composite, the human soul can’t lose its form and be replaced by another because it is a form. For a human being, the soul is the form of the body—that which makes the body a human body. Therefore, when the soul separates from the body, it can’t be destroyed by losing its form and by being replaced by another.
Since the soul is a form and therefore cannot be taken away from itself, nor can it be replaced with another form, and we know that the human soul can exist without the body, then it follows that the human soul by nature is indestructible, i.e., it’s immortal.
There is one last way the soul could go out of existence, and that is by way of annihilation. Annihilation is the reduction of something from existence to non-existence, which is an action that can in principle be performed only by God. Annihilation would not be due to anything in the nature of the soul itself but simply due to God ceasing to will the soul’s existence.
But we know God won’t do this, since it would violate his wisdom. It would be contrary to God’s wisdom to create a thing with an immortal nature only to thwart that nature. We can even go so far as to say that, given that God has created an immortal nature and given his immutable nature, he cannot annihilate the soul. He is committed to the nature of the thing he creates.
So, the human soul is of such a nature that it will exist forever if it exists. In other words, it’s immortal. And since we have good reason to think that God will not annihilate it, we can conclude that there is existence beyond the grave. And rather than an immaterial and immortal soul being a metaphysical rug under which we sweep our embarrassment for not having any explanation, the immaterial and immortal soul is a metaphysical rock on which we can build an edifice of faith in Jesus’ promise of eternal life in heaven.