Cartesian dualism is central to Descartes’s argument for the relationship between mind and body. Descartes builds this principle upon the abstract foundations set throughout the earlier meditations. There are five central facets of Cartesian Dualism, and it is by these five theses that the principle exists.
The first is T1 or the concept that the mind is capable of thought and consciousness. As stated by Descartes, we (the mind) are inherently “thinking things,” a self-evident truth that is virtually impossible to deny by virtue of our own existence.
This basis of thought is the originator of the meditations in their entirety, by that the certainty of our existence is the foundation for belief in any other principle. By admission, there is little argument against T1, as by and large it is considered an irrefutable fact and facet of our existence (in that we do, indeed, exist).
More debatable is T2, or the concept that the mind has virtually nothing in common with bodies. This is based upon the concept that the mind is wholly opposed to the body, in that it is a “thinking, non-extended thing” as opposed to bodies, which are “non-thinking, extended things.”
By this thought process, it would be impossible for this to be true as they are radically dissimilar by their own incompatible qualities. This belief brings about the famous mind-body problem, in that for the mind and body to have nothing in common, how do they interact with one another?
In the view of Kim, it would be impossible for the mind to causally affect the body should they share nothing. In his findings, he centers his argument on the Causal Principle or the concept that for something to influence something else it must be “spatially positioned in the right way.”
From this, it can be inferred that due to an immaterial mind lacking the ability to have a position, it would be virtually impossible for T2 to be wholly correct. Since these two things are incompatible, it can be inferred that minds must share some qualities with bodies.
Equally polarizing is T3, the belief that minds lack the ability to be separated due to their immaterial nature. In the view of Descartes, the mind is simply a unified consciousness, and a non-extended thing not bound by the laws of mathematics and so not capable of being split into distinct parts as something material could be.
Simply put, the consequence of this belief is that one cannot fully quantify and understand the relationship between the mind and brain, in that by the modern belief they are intrinsically related (if not the same thing entirely).
By the findings of Sperry, it is not only possible to split the mind, but based on reality. From his split-brain research, it was found that upon separation of the mind into distinct hemispheres, each individual side displayed an individual consciousness, wholly separate from the other.
Essentially, to divide someone’s brain is to create a division between certain aspects of the mind. This finding is wholly incompatible with T3 and thus it can be inferred this facet of Cartesian Dualism is incorrect.
The fourth thesis, or T4, is the belief that the mind is capable of an existence separate from the body. By the nature of the distinction between mind and body, he believes they can exist individually, even in the absence of the other.
In some ways, the most heavily debated of the 5 theses, modern findings have shown that the body (or more importantly, the brain) is intrinsically related to the mind, and have effects on the qualities or the existence of the mind.
Through his findings, it is shown that detrimental happenings to the brain (such as damage) can inherently affect the qualities of the mind. For T4 to be true, any effect on the brain should not be able to affect the mind, as the mind is wholly separate.
From this, one can infer T4 is untrue, as for mental faculties to be affected by changes to the brain, it cannot be a completely separated and unrelated immaterial thing. The final central facet of Cartesian Dualism, or T5, is the concept that the mind and body come together to form a union, the aptly named “mind-body union”.
Essentially, this is just a way to understand the ways in which the mind and body interact and affect one another. In a sense, the mind and body are two halves of a greater whole. There is not a universally accepted view of T5, however, based on empirical research different standpoints can be held.
The human being as it exists is a hard concept to grasp in its entirety, and while the truth in the relationship between sentient existence and our own physical bodies may not be fully understood, it can certainly be ascertained there is an intrinsic relationship to be had between the two, in that the two meld into one another until it is virtually impossible to tell a distinct separation between a “human being.”
