Substance Dualism vs. Materialism

At the center of the debate over human nature, the existence of free will, and the validity of science are two opposing viewpoints: materialism and dualism. Dualism is the belief that a person is made up of two kinds of substances: physical matter and above all else, an immaterial force known as the mind, or soul. Materialism refutes dualism, asserting that man and matter are inseparable, and that there is no mysterious, supernatural force directing our actions. Both viewpoints were derived in an attempt to place philosophy on firmer, more scientific ground. The arguments of Descartes and Hobbes for substance dualism and materialism, respectively, are representative of this debate. Although materialism and dualism have their own internal problems and flaws, I will argue that many of the objections that have been leveled against materialism can be met and that, on the whole, materialism is a much more plausible theory than dualism. The Greek philosopher Socrates believed that nothing could be certain without divine knowledge, which no man possesses. However, René Descartes, a 16th century French philosopher believed that some things could be determined to be certain as long as they were deduced through the proper methods. This method, known as the method of doubt, led Descartes to the foundational beliefs that became the basis for Substance Dualism. Simply put, Substance Dualism is the belief that there are two types of substances: the material body, and the immaterial mind. The existence of the mind, and therefore of thought, cannot be doubted based on the premise of “I think, therefore I am”. The body however can be doubted because belief of its existence relies solely on sensory experience, which can easily be misleading and false. Because something that cannot be doubted, such as the mind, could not possibly be the same thing as something that can be doubted, such as the body, the mind and the body are clearly separate things. Another form of dualism, known as Property Dualism, forms a sort of middle ground in between materialism and dualism. Property Dualism is based on the theory that all things are physical, but some things have properties that are not physical, or made up of matter or energy. According to this view, the physical does cause the mental, but the mental does not cause any physical event. This view doesn't assume any soul-like mind as a substance. There doesn't have to be any thing that's non-physical. This view agrees with materialism about which things really exist. The strangest thing about the view is that it's got one feature in common with parallelism - the mental stuff doesn't do anything. In essence, it states that our thoughts have no real affect on our mind. We cannot control our own actions with our mind.
Materialism, on the other hand, states that everything can be reduced to physical concepts such as mass, energy, and interactions between particles. Unlike dualism, materialism is often heavily backed and supported by physics and various other forms of science, besides the realm of philosophical theory and discussion due to its physics-only nature. There are 3 subtypes of materialism: Eliminative Materialism, Reductive Materialism and Non-Reductive Materialism.
Eliminative Materialism is one of the more extreme forms of materialism. While it still holds the belief that everything is physical, it goes a step further by adding in a specific language related thesis: all language associated with dualism, including “folk psychology” words like sadness and pain, should be eliminated entirely from our vocabulary. These words imply the existence of mental states that cannot be reduced to a physical state. These words are, based upon a strict definition of materialism, extremely misleading. Therefore, because they are so misleading and false it is believed they should be eliminated from language altogether to prevent confusion.
Reductive Materialism, on the other hand, holds the much less extreme view that only the material world (such as matter and energy) exists, and that all processes and realities observed in our universe can be explained by reducing them down to their most basic scientific components: atoms, molecules, and everything else thought to make up what we know as "matter."
Non-Reductive materialism takes an even more relaxed take on materialism, going as far as admitting that complex structures can in fact have irreducibly non-physical properties, like consciousness and free will. According to non-reductive materialism, mental phenomena are cause by neurophysiological processes in the brain and are themselves features of the brain. Mental states and brains states are not completely separate, but neither does this mean that there are no mental states, only physical. Mental states “just are” variations of physical states of mind. It is a natural part of the human brain, with no outstanding supernatural cause.
There are several arguments that lean towards materialism. Perhaps one of the most well known arguments is known as Ockham’s Razor. Ockham’s Razor is made up of two principles: The principle of plurality, which states that plurality should not be posited without necessity, and the principle of parsimony, which states that it is pointless to do more with what can easily be done with less. Simply put according to Ockham’s Razor, with all other things being equal, the metaphysically simple answer is the one most likely to be true. Therefore, assuming dualism and materialism are equally unproven, materialism is the more likely of the two, due to its simple, one sided solution compared to the two sided aspect that is the basis of dualism.
Evolution, one of the most likely scientific theories on the origins of mankind also favors materialism over dualism. According to evolution, man evolved from simpler beings, which in turn evolved from even more simple beings, who themselves evolved from non living proteins in a complicated but completely physical process. Given that non-living proteins have no mind of their own and is a purely physical being how would it be possible for the completely physical process of evolution to somehow instill a soul/non physical mind into the process somewhere along the line? If it was somehow instilled, when did this happen? Are one-celled organisms thinking things, or is it the more complex organisms that formed from them, such as monkeys or fish? If the dualistic mind was inserted later down the line, how was this done? Was it done at a gradual pace, or did the dualistic mind simply just pop up one day in the more evolved humanoid forms, magically leaving the less evolved monkeys in the dust? Neither Substance Dualism nor Property Dualism manages to answer these questions, which leads to the conclusion that in order to accept dualism, you would have to reject all scientific evidence of evolution.
Based upon the above argument, you could also say the same for the development of modern human beings. At one point in our lives, we were no more than two cells taken from our mother and father respectively, and fused into one. From this point, our cells began to divide again and again through completely and undeniably physical means. The process continues, a fetus develops, and eventually, a baby is born, which in turn one day grows into a full grown adult. If the now adult person has a soul, when did he acquire it? Like evolution, the reasoning and implications would be the same. Simply put, Dualism is forced to rely on an unknowable, magical intervention to create/insert a soul/mind into man. Materialism, however, does not simply rely on such unreliable influence to explain the actions of humankind.
Although dualism argues that the mind and the body are two completely separate things, it fails to explain why, when there is damage to the brain the mind is affected as well. Time and time again, cases of brain damage as well as chemical imbalances, two very physical aspects, have undeniably been shown to have a profound affect on the mind, something that is supposedly immaterial. But, if the mind truly was immaterial then how could the physical aspects of brain damage and chemical imbalance possibly affect the mind?
Although dualism certainly has its own objections, materialism is not an exception to objection, either. Dualists have presented several objections to materialist views, which I will now address and add my own response to these objections. The first objection follows as such: materialism says that everything can be reduced to a physical concept, like mass and energy, and relationships between elementary particles. But pain is not a physical concept and therefore cannot simply be reduced to physical concepts. Pain does indeed correspond to physical processes, however the feeling, the actual sensation of pain itself is not physical, a concept such as pain would never be found in a physics book. Therefore, either I do not really feel pain, or materialism is false. This objection does raise a good question, however it has one serious flaw: if the actual sensation of pain itself isn’t physical, how is it that chemicals like morphine and vicodin are able to lessen or completely take away pain? If pain truly were a non-physical entity, then operations would be extremely traumatizing and painful. The causes of emotions themselves, something that according to dualism is part of the mind and therefore has no physical attachment to the body, have been definitively linked to physical chemicals such as Dopamine, Serotonin and Norepinephrine. By raising and lowering these chemical amounts in the brain, emotions are obviously affected, such as feeling of happiness and euphoria increasing as the chemical levels of Serotonin are increased. If the mind really were separate from the brain, then chemicals would not be able to affect thoughts and emotions.
The knowledge argument describes a future scientist who has lacked a sense from birth-such as hearing. However, his main field of study has been the ear, so he has a perfect understanding of how it operates on others. Although he is deaf, he is considered the greatest expert on the mechanics of hearing, knowing everything there is to know on a physical and behavioral level. One day, this scientist undergoes an operation that finally allows him to hear everything. It is assumed that after the operation he will now learn something new about the ear, which is the actual first person experience of hearing itself. These qualitative experiences are known as qualia. If the scientist learns something new, he did not know anything beforehand. He knew only the physical facts before, so what he learns from actually being able to hear- the nature of qualia- are not physical. According to dualists, this would prove property dualism, and disprove materialism.
However, there is a problem with this argument. Although the scientist’s new knowledge is factual, it is not actually knowledge of a new fact. Instead, he has instead found a new way to understand something he already knew. He may not realize this because the concepts used to experience things first hand (like recognizing color and sound variations) are very much akin to demonstrative concepts. Demonstrative concepts do not have the kind of descriptive concept that allows people to infer what they are experiencing from pre-existing knowledge. The original knowledge the scientist initially had did not allow him to anticipate what it would be like to re-express these demonstrative concepts that are derived from experience and experience only. Therefore, it is reasonable to conclude that the knowledge appears to be new, when in actually only the method in which he conceived it was novel.
In conclusion, both dualism and materialism have their own flaws. However, seeing as the belief in dualism requires throwing all scientific knowledge and understanding of the brain and the human body out the window, in the end, materialism is the much more reasonable and plausible of the two options.