Substance Dualism and Materialism: John Locke and David Hume

Descartes’ Substance Dualism

To begin the discussion of Substance Dualism and Materials, the philosophical positions should be clearly explained and defined. Dualism originated from the philosophical ideas of Rene Descartes, in particular, the philosophy regarding dividing the mind and body that had a great impact on the development of philosophy and medicine in the seventeenth and eighteenth centuries. The main idea of Descartes’ philosophical concept lies in the belief that mind and body are separate notions: spiritual and physical. The body has such properties as mass, color, weight, and size as a physical subject; hence, it complies with the physical rules of the universe. According to Descartes, the mind or soul is an immortal substance, which does not have any physical characteristics in contrast to the body, and therefore, it is not a subject to the tangible universe. Descartes states that the soul is a thinking substance and the body is purely a mechanical object, which is controlled by the brain.

Descartes’ substance dualism is based on the belief in the existence of God. Consequently, the soul is the part of the matter that has its own existence, and it can exist without the body. However, the body cannot exist without the soul. The best way to describe Descartes’ substance dualism is to compare the human body to a car and the soul to the gas. Even the most powerful and the newest car is only a set of metal details if it does not have any gas. The same concept can be applied to the human body: body is only a set of organs and tissues, which are connected to each other, without the soul. Gas can be used for many different purposes but a car is useless without gas.

According to Descartes, ability to feel and think is the defining property of the soul. In other words, people’s beliefs, dreams, desires, and doubts are not the result of the chemical reactions in the brain but the results of the presence of the soul in the human body. Such feelings as love, hate and hope neither have physical property nor belong to a material substance.

Materialism

Materialism is completely opposite to dualism philosophical theory. According to the theory of materialism, humans have nothing except the physical body. Materialists state that this is a primary idea and all the theories follow from it. The great complexity of the universe is reducible to the matter and nothing exists apart from matter. Materialistic vision can be explained by using the example of a computer, where the universe is hardware and DNA is a software, which is a product of hardware according to materialism.

Reductive and eliminative types of materialism are considered to be the most popular among other types of this philosophical concept. In fact, two types of materialism are significantly different. The reductive materialism, which is also known as the identity theory, is based on the idea that all the kinds of human brain activities can be reduced to the neurophysiological processes within the human body. Reductive materialists accept the existence of the conscious mental phenomena. However, this idea also states that the consciousness and the brain are one and the same. Actually, materialists accept that there are conscious sensations, perceptions, emotions and thoughts that go inside the human head. There is a subjective psychological reality. Nevertheless, materialists deny that the subjective psychological reality is anything different from the brain as an objective neural reality. In other words, the main idea of the reductive materialism is to reduce all the complicated emotional and mental processes within the human body to the neurobiological, chemical, and neurophysiological reactions.

In contrast, eliminative materialism tries to eliminate the notion of consciousness from science. Eliminative materialists base their arguments on the history of science, which has the evidence that these phenomena turn out to be illusions. From the perspective of eliminative materialism, there is no such thing as mental state. According to this philosophical theory, all the types of human emotions such as free will, hope, love, hate and desires are only the illusion of the reality because all of them are nothing else but various reaction within the human body. Materialists support their argument by pointing out that none of the mental processes exist outside the body. Consequently, human emotions are not material, and therefore, do not exist.

Comparing two types of materialism, it is possible to state that the main difference is that the reductive theory does not deny the existence of feelings and emotions even though they are reduced to the neurological level. On the contrary, eliminative materialism theory states that things, which cannot be measured scientifically, do not exist.

Substance Dualism in Comparison with Materialism

Comparing dualism to materialism, it is evident that the first philosophical theory provides a more plausible answer to the mind/body problem. Both reductive and eliminative materialism seems to leave the subjective, qualitative aspect of human mind unexplained. The subjective sensory-perceptual and cognitive-emotional reality people experience in their consciousness cannot be fully described by neurophysiology. For instance, despite the fact that such feeling as love can be explained from the neurophysiological perspective, the chemical reactions in the brain are caused by the feeling not vice versa; otherwise, it would be possible to force an individual to fall in love.

Consciousness neither can be dismissed as an illusion nor can it be just a result of coarse perception of the true microphysical reality. In fact, it is impossible to perceive consciousness as a physical object using any external senses. What is the purpose of the human existence if materialism theory was right? Or what is the point of morality if people are only the soulless set of molecules connected to each other? What makes people so different to animals? Dualism gives perfect answers to all these questions that makes it more plausible and realistic.

The Problem of Personal Identity

Many philosophers have various opinions about the problem of personal identity. Some of them believe that a personal identity stays the same throughout life; others believe that human nature tends to change over time. John Locke raised a question whether there is something that stays unchanged within the human nature and distinguishes one individual from others. Locke’s formulation and position on the problem of personal identity is among the most frequently studied and discussed theories by philosophers.

John Locke argues that personal identity stays the same independent of the individual experiences. The philosopher based his argument on the human memory. Locke states that each individual is a thinking being and has his/ her own memories, principles and experiences, which define personality. According to John Locke, the consciousness is a key component of the personal identity. The philosopher does not deny the existence of the soul; however, he denies the impact of soul on identity.

Another philosopher, David Hume offers an interesting and revolutionary vision on the problem of personal identity. The philosopher states that personal identity does not exist. From Hume’s perspective, the mind is nothing more but the system of perceptions. People are changing every day due to various situations and circumstances. People’s impressions and ideas can be changed by new experiences and knowledge.

David Hume supports his theory by drawing attention to the elusiveness of the self by claiming that, when looking at himself, person can hardly detect individual thoughts, memories, and experiences. While it is natural to imagine a self that is the subject of these thoughts, the philosopher argues that it is wrong: the self is not more than the point of view regarding one’s thoughts and experiences. Thus, according to Hume, every time someone pictures himself it will always be a different picture.

Comparing two visions on the problem of identity, it is possible to claim that Locke’s statement provides a better answer to the problem. Despite the fact that people certainly change during their lives, some things remain the same. For instance, any child forms his personality during the first few years of life. There is no doubt that parents and environment play a significant role in the development of personality. However, each infant is born with certain qualities of the character. People might change some of their tastes, opinions, and even perceptions. However, once they shaped their character in the childhood, it would hardly change later. Thus, character determines each individual. In other words, different people react differently in the same situation. Such reactions are based on principles, tastes, mental, and psychological condition of each individual.

In conclusion, it is possible to notice that both of the philosophical theories are not perfect. John Locke goes to one extreme and states that personal identity does not change; at the same time, David Hume goes to the other extreme by stating that there is no such thing as a personal identity. One can conclude that the philosophies disagree on the issue of personal identity. In order to derive an appropriate answer to the question, the ideas of two philosophies should be combined. Thus, the perfect answer to the question would be the following: all the people do change but only to a certain level.

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