Descartes’ most famous words—Cogito ergo sum (I think, therefore I am)—are so powerful because of their intrinsic validity; no one can question their truth. Nevertheless, what follows from this premise in Meditations on the First Philosophy is Descartes’ thesis that mind and body are completely separate and distinct entities (page 139). He also believed that because of this separation, the mind is unaffected by and can outlive the body (insert page #). In contrast to the undeniable and well-founded nature of Descartes’ “cogito ergo sum”, these declarations are both inexact and under-justified.
It is impossible for the mind and the body to be separate. To properly argue this point I present my own logical train of thought (in the Descartes tradition) starting with Descartes foundational idea of being a mere “thinking thing”. The mind cannot be without perceptions, which cannot be conveyed in the absence of senses. It follows that to have senses, one must have a body outfitted with sensory equipment. Because of this close association and mutual dependence the mind and the body share, it follows that if the body is affected in some way, so too will the mind be. As for matters of the spirit or soul, perhaps it is an element inhabiting the mind and the body as one, as they are inseparable.
In the Meditations on the First Philosophy, Descartes begins the creation of an intellectual rebirth; building up from the foundation of his knowledge in assessing the validity of information conveyed to him by his senses. Starting in the third meditation, Descartes begins to doubt everything, stating that because he has learned everything through his unreliable senses, he can know nothing for certain apart from the fact that he is actively doubting (page #). Descartes deduces himself to a mere “thinking thing” (page #), a lone entity floating in space with nothing but intellect for company. What should have instantly dismissed the idea of the possibility of being a mere “thinking thing” from the very start of the meditation is the fact that Descartes could not rationally deny his own senses.
Descartes’ willingness to believe that he may not have senses betrays an underlying fact in order to have any kind of information or ideas to actively deny, one must necessarily have senses which transmit information to the mind about the physical world outside the intellect. Descartes’ own ideas of the world, memories, and perceptions serve as evidence of communication from the outside world to his mind—even if he chooses to reject what was transmitted as hopelessly flawed.
Descartes himself asserts that something cannot come from nothing (page #). By this logic, a “thinking thing” cannot know what to think unless given a foundational mental archive of information. Without experiencing anything outside of itself and not receiving any stimulus from the senses, thoughts would be impossible for a thinking thing. The fact that Descartes is trying to deny information he previously believe to be true proves that his mind has gleaned knowledge from outside of itself by some means of sensory extension.
For example, when people think, they do it with the aid of language. Descartes never once explains or considers the fact that he is thinking in a language—a tool that obviously had to be learned from an outside source. While a similar conclusion is eventually reached in Meditation VI, the acknowledgement of the senses should have been first verity—clear beyond a reasonable doubt.
After having accepting the fact that senses are indisputably real, one naturally comes to recognize the need of a body, since there must be some kind of extension through which the senses convey information. Again, using Descartes undeniable assertion that something cannot come form nothing; it must be true that senses have a physical reality. They must have this in order to interpret and communicate information about a physical world. A body is a means of physical extension by which the senses operate. Since one can be certain that senses are real, and because the senses have constantly conveyed information of the presence of a body, one can rationally be certain that the body too, is real. Baby.
Throughout all of his meditations, Descartes maintains that the mind is purely a “thinking thing” (page #) med II. This is the position of Antonio Damasio in Descartes’ Error: “the comprehensive understanding of the human mind requires an organism perspective; that not only must the mind move from a nonphysical cogitum to the realm of biological tissue, but it must also be related to a whole organism possessed of integrated body proper and brain and fully interactive with a physical and social environment.” (page #)
There is no way of proving that the mind can exist without a body. Our way of experiencing seemingly intangible mental activity may be no more than the phenomenon of chemical signaling between neurons in the brain and throughout the body. It is not impossible that there could exist a purely “mental” realm outside of our physical awareness, however because our minds are so tightly intertwined with our bodies, we have no sure way of knowing. What we can be sure of is that our minds have a physical basis in our bodies.
What must next be argued based on what has been established above are Descartes assertions regarding divisibility of the body verses the mind. In Meditation VI, Descartes comes to decide that though there is some inexplicable means by which the mind and body are linked, they remain two different things. Based on this assumption, he comes to decide that the mind is indivisible while the body, by design, is divisible (page 139). Descartes does not provide a solid logical argument for his assertion. When discussing the divisibility of the body, Descartes abandons his style of lengthy and well-thought-out line of reasoning. Rather, he holds that an amputee, though physically divided from a limb, would suffer no mental alteration.
While it is true that a person can survive after losing a foot, it is also true that the mind loses access to all of the information the lost foot would have conveyed about the world: ground motion and temperature, texture, and surrounding material. The foot also gave the body the ability to walk, run, and balance. In this example, division of the body through the loss of a limb would lead to a void of information in the mind. Every component constituting the body is considered and accounted for in the mind. When thinking of doing something or going somewhere, the mind takes in to account all advantages and hindrances of possible future actions and analyzes a plan of action. The mind does this constantly and mostly, unconsciously.
In the absence of an appendage the mind must adjust and re-diagram plans of action. It must also make up for the fact that it has lost all of the sensory input that once came from the lost appendage. Certainly in the case of losing more vital parts of the body such as a lung or heart, the mind would be deprived not only of the sensory input, but also of a resource needed to survive; it would be physically altered beyond repair. For these reasons, it is evident that the body is not so easily divisible as Descartes, never having lost a limb himself, implies.
In regards to conditions of the mind, Descartes’ chief reason for asserting that the mind is indivisible is that upon introspection, he can only understand himself to be one complete thing. In making this statement about the mind, Descartes is not referring to the brain; rather, he is referring to an entity outside of the brain. An intangible intelligence. As previously discussed, as far as we can rationally prove, the brain and the mind are one in the same. Because The Meditations on the First Philosophy was meant to be an analysis on gaining certainty of reality using a systematic and rational method, the consideration of indivisibility of the mind must be argued in terms of the brain.
One of the most famous, more modern examples proving the divisibility of the brain is the case of Phineas Gage. Though there were undoubtedly many cases of people surviving brain damage in the time when Descartes lived, the accident endured by Phineas Gage is well known and well documented. Phineas Gage is a man made famous for his survival of an accidental lobotomy. After being impaled by a metal rod through the frontal lobe of his brain, Phineas Gage remarkably, made a full corporeal recovery.
However, following the accident, there was evidence of profound personality change. (Source) From all that we humans have learned about ourselves in the ways our mentality works, evidence such as brain damage, and its capability to completely change a person, this seems evidence enough that our minds are divisible; that they are an ever-changing entities that can survive in cases of severance. As far as a “soul” is concerned, we have no solid evidence proving any such thing exists. So how can Descartes scientifically speculate matters regarding its characteristics, and particularly, its possible “divisibility”?
The case of Phineas Gage reinforces the argument that the mind and body are not, divisible; those unhealthy in the mind are also unhealthy in the body, and vise versa. One cannot be whole without the company of the other. As for matters of the soul, they are purely speculative as they cannot be supported by any kind of evidence, and should be left to faith alone. [Author: You need to source the Gage case in the text and in your References at the end]
Despite inconsistencies in Descartes’ treatise, his ideas continue to challenge conventional wisdom, just as they offered a new perspective to people trapped in the close-minded society of his day. Descartes provoked readers to think for themselves, an action which was at that time punishable by death. Though he would never fully know the extent to which he affected society, his dream of stimulating new ways of thinking became a global phenomenon that continues in the contemporary world.
If it is essentially the “soul” to which Descartes is referring when he uses the Latin word for “mind”, than by Descartes own standards laid out in his Discourse on Method, specifically, his rule to never believe anything to be true unless he himself can prove it (insert page #), it can never be proven, for one would have to die first to be sure.
Damasio, A.R. (1994). Descartes’ Error: Emotion, Reason, and the Human Brain. New York: Putnam Publishing.
Descartes, Philosophical Essays and Correspondence (cir.1641). Translation by Donald Cress (1993). Indianapolis: Hackett Publishing Company.
Grassian, S. (1983). Psychopathological Effects of Solitary Confinement. American Journal of Psychiatry, 140, 1450-1454.
Grassian, S. & Friedman, N. (1986). Effects of Sensory Deprivation in Psychiatric Seclusion and Solitary Confinement. International Journal of Law and Psychiatry, 8, 49-65.
Sutker, P. et al. (1991). Cognitive Deficits and Psychopathology Among Former Prisoners of War and Combat Veterans of the Korean Conflict. American Journal of Psychiatry, 148, 67-72.