There is a wide variety of categories into which all that exists in the world can be divided. There are natural and unnatural phenomena; objects created by humankind and those we consider to be a product of the Supreme Mind; there is flora and there is fauna; there are items that we can modify and entities that humans have no control over. One of the many ways to differentiate and classify everything and anything in the surrounding environment and, probably, one of the most universal ways, is to classify what exists as being either material or immaterial. It seems fairly easy to distinguish between the two. If we cannot touch, feel, or see what is existing, then it becomes the notion of the immaterial world. The rest belongs to the material realm, which we can own, trade, purchase, possess, lose, or give away. When Rene Descartes, one of the founders of modern-day western philosophical science, laid the groundwork for his epistemological perspective called Cartesian Dualism, he was coming exactly from the same universal idea. The thoughts and hypotheses that Descartes tried throughout his lifetime’s work to develop into axioms and prove to be fundamentally true surprisingly remains highly debatable and are still largely in question.
Philosophy is much about the question of certainty. To a great extent, from the epistemological perspective, knowledge is certainty (Harris, 2009). Just as the case is with Plato, whose quest for certainty has driven his metaphysics to take it, as a prerequisite, that if something is known, then it cannot change (Frank et al., 2011). Descartes too attempted to deduce the formula that would be true for all cases. However, while for Plato, it was the form that was the aspect we could consider to be unchanging and constant forever; the form as immutable, timeless, indivisible, indestructible, transcendent object of pure thought—Descartes attempted to solve the problem of certainty in his own epistemological quest by drastically different means. By saying that what there is, is that we cannot know, Descartes outlined the pathway that all representatives of western philosophy after him would take.
When it comes to engaging in philosophy, every philosopher will agree that there should be a starting point—an expression that we consider as a certainty (Fraire&Jenkins, 2008). From this point, different theories and streams can be developed depending on what this point is and how we choose to look at it. For Descartes, that point heavily relied on the Law of Noncontradiction, since the French philosopher chose to doubt everything in order to detect if a concept was unmistakably true and certain, unequivocally. Just like a notion cannot be true and false at the same time, if we unmistakably prove that something is material, it cannot be considered otherwise. If there is a computer in front of me and I am sitting on a chair, can I doubt that there is a computer and a chair in the room? And, if I doubt this, will I not be contradicting myself? This Law of Noncontradiction can serve as a helpful tool in checking any theory and idea. However, with his Cartesian Dualism, Descartes managed to doubt even this law.
When we divide entities into material and immaterial, we base such division on our senses: hearing, feeling, smelling, tasting, and seeing. But what if our senses are not to be trusted? What if our senses can deceive us into believing something that is not there? The case is certainly to be considered, since there can easily be found real-life examples of such a scenario. When persons are hallucinating, they think they are seeing a phenomena that is not actually there. If they see a chair and consider it to be material, but in fact that chair is the product of their imagination, then it is on the contrary: an object of the immaterial world. How can we talk about certainty when distinguishing between material and immaterial notions?
In solving this problem, Descartes suggests a number of qualities for the immaterial and material that will serve as indicators of one or the other. The main quality of the material is that they occupy space, since their physical existence dictates this rule. The immaterial, on the contrary, cannot exist in space, but they can think, producing other immaterial entities (Benett, 2008). To better understand what Descartes meant by claiming that the immaterial world can produce thoughts, it is important to understand where the philosopher was coming from. If we think of ourselves as only the material matter (we can be felt, we occupy space, we can move other material objects), we will stumble upon one of the traps that Descartes has warned about. The French philosopher thinks of himself as both the material and the immaterial object, since he has both the Mind (the immaterial part) and the Body (the material part). His Mind cannot produce physical objects without the help of the Body, but it can produce thoughts. It cannot occupy space, but it does not mean that the Mind does not exist. Cartesian Dualism came to be known as the problem of Mind and Body, meaning that the existence of links between the material and immaterial, especially as undoubtedly as they are within everyone of us as an integral organism, make Cartesian Dualism arguable and innovative at the same time.
Descartes in no way attempted to avoid or ignore the questions that Cartesian Dualism put before him—he introduced the idea of causal interactionism. The material and immaterial, the Mind and the Body, interact with each other, constantly causing changes in the nature and state of each other. We can hardly argue the fact that the state of our bodies affects the state of our minds. If a human being is physically in pain, meaning that the body is unwell, the mind also suffers and the thoughts that the mind produces, at the time, are very much due to the state of the body. Furthermore, it has long been argued by many doctors, scientists, and psychologists that the way we think also greatly affects our physical state. Just like Hans Eysenck once suggested that it is not the tobacco smoke that causes lung cancer, it is the thoughts of emotional dissatisfaction and depression which cause cancer cells to split and multiply within our bodies. This makes the Mind and the Body interdependent on multiple levels. What bridges and links the “I” as a soul and the “I” as a body for Descrates is God. God plays a significant role in Descartes’ metaphysical view of reality. With the need to form a certain understanding about the world around him, Descartes introduces God as the most powerful Mind. This Mind will not let Descartes deceive himself about notions this fundamental and this important. Therefore, according to the fundamentals of Cartesian Dualism, there is the Mind, the Body, and the world (Frank et al., 2011).
The only way for Descartes to trust his ordinary beliefs about his surroundings is to trust that there is a world beyond his mind and this world is controlled by God as an absolute power. Descartes knows there is a world, because he knows there is a God. God in Cartesian Dualism, unlike God in most of the world religions, was not introduced to save us, but rather to help us solve those eternal basic philosophical problems that could not have been solved otherwise (Harris, 2009). Without this idea, the whole theory of Cartesian Dualism would have collapsed, not having anything to rely upon outside the mind and the body of self, ignoring the very existence of any world outside. For Descartes, there is the “I,” God, and the world. Some minds have bodies to them (like human beings), some do not (like God); some bodies have minds to them, some do not (like pieces of furniture). While some minds and bodies can interact and cohabit within one organism, others cannot.
If people today were asked to physically locate the Mind within themselves, most would probably locate the Mind in their head. Few might point to the heart area. But, for Descartes, this situation is more complicated than that and the question of how to locate the Mind within the body has brought Descartes to one of the major dilemmas within the epistemological perspective of Cartesian Dualism. If it is the prerogative of the body to be extended (to occupy space), then how can we physically locate the Mind? From the Cartesian point of view, when asked the question of where your mind is, your answer would be to tell what you are thinking. In this regard, the Mind is not locatable in space. Nevertheless, Descartes does situate the point of interaction of the Mind and the Body in the pineal gland. Does the French philosopher contradict himself with this act? If the Mind is not a material object, how can it be physically located at a certain specific place within the body? And, if Descartes has decided to compromise the very idea of immaterial, unlocatable Mind, does he not betray the essence of his theory (that is, the idea that the Mind is a wholesome element that is equal to body, instead of being a part of it)?
These questions seem to constitute the biggest weakness in the Cartesian Dualism, while along with many other oversights, they have allowed a number of theories and streams to form that root in the idea of the dual nature of all that exists in the world. This may seem to some like proof of the contradictory nature of the epistemological perspective of the Cartesian Dualism. Nevertheless, most modern philosophers agree that Descartes’ ideas have, in fact, served as the perfect foundation for the development of the philosophical ideas in various directions, allowing these diverse streams to form the basis for everlasting debate within metaphysics. It became such a plentiful source of food for thoughts that the role of Descartes in the development and ramification of philosophy to this day can hardly be overrated. After all, philosophy would stop being philosophy if there was nothing more to doubt, question, and build theories around.