In last month’s column I set the stage for a series of columns analyzing and explaining the constitution of human nature from a Catholic philosophical perspective. This present column will be the first of the series. My goal in this particular column is to establish a fundamental distinction in human nature between the physical and the immaterial. The view that human beings are nothing more than complex systems of physical matter seems to be commonplace in our culture. We are often told that there are no deep qualitative differences between us and other animals, that all of our emotions, desires, passions etc., can be explained by brain chemistry and/or neuron firing, and that the human mind just is the brain which can be understood and manipulated like a computer. Our faith tells us, however, that humans are not wholly material. We have immortal souls that are destined for eternal life or eternal death depending on our life choices. How then should one respond to the above claims?
Naturalism vs. Non-naturalism
For the sake of clarity, I think that what’s important to highlight at the outset is that typically, one’s views regarding human nature are a natural extension of one’s views regarding the natural world in general. If, therefore, one wishes to be clear in his views regarding human nature, he should also clearly understand how he thinks about reality in general. This will go a long way to dispel the appearance and substance of any post hoc ideas or special pleading within one’s own thinking. So, those who argue that human beings are purely physical creatures are very likely to say that all of reality is made up of matter and nothing more. This view is called materialism or naturalism, and it comes in many varieties. The relevant point for our purposes here is that naturalism is the view that reality in general, and human beings in particular, are entirely explicable via physical methods and investigation. The question now becomes, does naturalism provide an adequate explanation for the nature of reality?
This is an ancient question that has been debated at least since the time of the pre-Socratic philosophers, if not earlier. Let us take the positive answer. Those who hold to naturalism today are likely to say they do so because science is extremely precise, complex, and all-encompassing. We can use scientific methods in everything from political campaign messaging to medical treatment and astronomy. We have also seen massive expanses in scientific understanding and development which has resulted in many technological advances from space rockets, to smart phones, and nuclear-powered submarines. A proponent of naturalism could also say that a purely material explanation of reality is more parsimonious than a non-naturalist explanation. Naturalists can account for all of the phenomena we see and experience without bringing in all of the non-material substances like souls, God, angels, etc., that non-naturalists do. So there is an argument from the power and scope of scientific methods, and there is an argument from parsimony to support the naturalist position. What can a non-naturalist like a practicing Roman Catholic say in response?
In response I think one ought to say that both of these arguments beg the question against the non-naturalist. That is to say these arguments actually assume their own veracity rather than establish it. Science is indeed very powerful and very important, and its scope is far and deep. But in order for these arguments to be true, science must be able, in principle, to explain everything in reality. Now, does it seem plausible that science can do this? Can science explain why murder is wrong? Can it explain why Shakespeare and Chaucer were superb writers? Science can tell us everything about the chemical makeup of the paint on the ceiling of the Sistine Chapel. But can science tell us the meaning behind the paintings and why they are so beautiful? It should be clear that science cannot provide us with adequate answers to any of the above questions and many more like them. The reason is because the above questions are concerned with meaning and with the quality of actions, objects, and intentions. Science is only concerned with quantity, measurement, and experimentation. This does not mean that the above questions are not rational questions. It only means that we need other rational methods besides the sciences in order to investigate them.
The Power of Thought
Now, none of this in itself goes so far as to show that there is an immaterial component to human nature or that naturalism per se is erroneous. After all, the ceiling of the Sistine Chapel and the works of Shakespeare are clearly material in nature. But these considerations do help point us in the right direction. Consider the fields of study mentioned so far. Humans study science which has a wide range of sub-disciplines. We also pursue art, literature, and psychology among many other things. What we look for in pursuing these studies is knowledge and ideas. We want to increase our understanding of the world, ourselves, our actions etc., and this leads to the discovery of many new ideas. Herein, according to St. Thomas Aquinas, lies an argument for the immateriality of the human mind. I will reconstruct it below.
The mind is the power by which we analyze and entertain ideas. For example I can entertain the idea of a lion in my mind. My mind can also entertain many other ideas like triangularity, law, love, philosophy, etc. Everyone’s mind is capable in principle of doing this. Now, if human beings were wholly material then our minds would, naturally, be material. If our minds were material how then could we entertain one or more abstract ideas? If a material thing contains the idea of triangularity, then that thing just is a triangle. If something material contains the idea of law then that thing is some type of written document. If a material thing contains the idea of a lion then that material thing just is a lion. So too, if the human mind were wholly material then once it contained one idea, it would become the physical manifestation of that idea. But when I entertain the idea of a lion or a triangle, neither my mind nor my brain becomes a lion or a triangle. Because we are able to entertain abstract ideas in our mind without actually becoming any of the things we think about, the human mind must be immaterial. Let us consider this further.
It might at first seem strange to say that being capable of abstract thought is indicative of immateriality. However, this is a natural consequence of the veracity of the ideas that we have. Consider the lion example again. In order for a biologist’s idea of a lion to be true, the idea has to match what the nature of a lion actually is as it exists outside of the biologist. If the idea does match the lion’s actual nature, then that means that the idea of a lion’s nature that the biologist has in his head, and the lion’s nature as it exists in the world, are qualitatively the same. But for the nature of a lion to exist in material reality just is for a lion to exist. However, the idea of a lion’s nature exists in the biologist’s mind without the biologist himself or his mind actually becoming a lion. Since this idea is qualitatively the same as a lion’s nature we must conclude that the human mind is immaterial since it can contain the idea of the nature of a material thing without actually becoming that material thing itself.
Now, much more could be said in development and defense of this argument, but this is sufficient for our purposes here. There are however, many questions that still remain unanswered. Given that there is some immaterial aspect of human nature i.e. the mind, one could still ask, what is the mind’s relation to the soul? Is the will immaterial? What is the soul/mind’s relation to the body? Does this mean the body is worth less than the mind? Given that there is an immaterial aspect of human nature, what implications does this have for how we ought to live? These are questions I will return to in future installments of the series.