Mind Or Matter: a Critique of Descartes’s Philosophy

In the Second Meditation of The Meditations on First Philosophy, Descartes addresses the question of identity: “I am, I exist… But this ‘I’ that must exist––I still don’t properly understand what it is.” (Descartes 4) The only circumstance helping establish identity is that Descartes thinks––in fact, it is the only thing he can guarantee. Therefore, one can come to the conclusion that in establishing that he is essentially a thinking thing, Descartes also establishes that identity is dependent on the mind, not the body. This distinctive attribution of what a person truly is sets the stage for Descartes’ ideas of mind-body dualism, in which the mind and body essentially exist as separate entities. Descartes’ argument takes two major forms––divisibility, dubitability, and conceivability––each of which can be deconstructed to deductive arguments to prove the difference between mind and body. However, there exist logical fallacies and discrepancies in the premises and conclusions that put the validity of Descartes’ dualist position to question.

The logical argument for divisibility in support of dualism is as follows:

All extended things are divisible.
No minds are divisible.
No minds are extended things.

Upon initial contemplation, the first premise seems to be true. In the extended world, matter is constantly changing form, reshaping, or breaking apart. It is simple to conceptualize physical things being divided. Take an apple, for example––cut it in half, pull out the core, slice it into wedges. What would happen, however, if we took things further? We would divide it into smaller and smaller sections, until the piece of apple was so tiny it could not be cut with a knife. Still, the apple exists and a physical, extended thing. And so we can divide it further, to a single piece of matter, to a single atom, to its atomic components––electrons and quarks. But then what? We started out with an apple, which is undoubtedly an extended thing, so surely the matter we are left with is also an extended thing, being produced by the division of some physical object. Yet, by continuing to divide the apple into its simplest components, we are eventually left with pieces of an extended thing that is in its purest form, and is no longer divisible. Thus, the first premise stating that all physical things are divisible cannot be true.

If the first premise is false, the second premise is rendered useless. Whether or not the mind is divisible tells us nothing; there is no correlation between extended things and divisibility. Even if the second premise were assumed to be true, there would be no way of concluding that “no minds are extended things”, as the quality of indivisibility tells us nothing of the physicality of an object. The second premise in itself is not completely sound, for in some senses, the mind actually is divisible. While the divisibility in question with the first premise is on of spatial divisibility, it can be argued that the mind exhibits temporal divisibility. Everyone, at one point or another, has experienced a “blank moment” or dreamless sleep, during which no images or thoughts subsist in the mind. In these instances, continuity of the mind is broken. Descartes states in the Second Meditation: “I conclude that this proposition, I am, I exist, must be true whenever I assert it or think it.” (Descartes 4) Upon rejection of the divisibility argument’s second premise, Descartes’ identification of himself solely as an essentially thinking thing is no longer reasonable, as, should Descartes cease to think, he would cease to exist as well. There are moments in the everyday, such as the instances mentioned previously, during which consciousness takes respite.

The Second Meditation also introduces the doubting argument, which can be summarized as follows:

I can doubt that my body exists.
I cannot doubt that I exist as a thinking thing.
I, as a thinking thing, am not identical with my body.

When considering the argument in itself, the conclusion does not follow from the premises. The justification issues lie in deciding what determines identity. The following is a modification of the doubting argument, which “makes use of Leibniz’s Law of Identity… x is identical to y if, and only if, for any property p had by x at time t, y also has p at t, and vice versa” (Calef) through the addition of another premise.

My body has the property of being such that I can doubt its existence.
I, a thinking thing, do not have the property of being such that I can doubt my existence.
If two things are identical, then they have exactly the same properties.
I, as a thinking thing, am not identical with my body.

In applying Leibniz’s Law, Descartes establishes the mind and body to be different entities because they do not have the same property of dubitability. While the modification make the argument logically sound, the issue lies in whether or no dubitability is a property that can even be used for an object’s identity––“doubt… is a property of me, not of [the object in question].” (Calef) In other words, to doubt is to be without conviction or to believe something to be uncertain. Objects do not inherently possess the quality of being dubitable; it is applied to them by the doubter. Therefore, because Descartes doubts the existence of his body but does not doubt the existence of his mind, it does not follow that the two things are essentially different. While Descartes provides his reasoning for why he doubts the external world and why he believes the mind to undoubtedly exist, one could just as easily hold views that were the exact opposite, and the premises would still hold true from the conclusions. This proves that doubt, in itself, no matter how strongly backed, is not a sound measure of identity comparison.

Descartes’ conceivability argument, as introduced in the Sixth Meditation, falls under a similar margin of error:

I can conceive that I, a thinking thing, exist without my extended body existing.
Anything that I can conceive is logically possible.
If it is logically possible that X exist without Y, then X is not identical with Y.
I, as a thinking thing, am not identical with my extended body.

Similar to how dubitability is not a possessive property belonging to an object that renders it to be a certain way, conceivability, as used in the first premise, neither confirms nor denies any thing about the nature the mind being separate from the body. One could just as easily conceive of a world in which the mind and body are mutually necessary. Ex nihilo nihil fit––a phrase first coined by the pre-Socratic philosopher Parmenides, meaning nothing comes from nothing––is the main principle on which the second premise is based. “Anything that I can conceive”, or ideas, are attached to what Descartes considered objective reality, which is merely comprised of representations. What they represent are elements within formal reality, which are things solely of the external world, things that are “logically possible”. Despite this connection, they still take distinct and separate forms.

However, to what extent do these ideas within objective reality have to correlate with their formal reality counterparts? Take, for example, the fantastical beasts mentioned in the First Meditation: “For even when painters try to depict sirens and satyrs with the most extraordinary bodies, they simply jumble up the limbs of different kinds of real animals, rather than inventing natures that are entirely new.” (Descartes 2) Satyrs and sirens are things that exist only in objective reality. Their formal connections are not actual satyrs and sirens themselves, but rather the physical figures of humans, goats, and fish, the formal elements which the mythical beasts are comprised of. As a result, the second premise does not stand to be completely valid. A conception is derived from things that are logically possible, but it is not true that anything conceivable is logically possible. If this were the case, there would be no such thing as fiction.

Descartes proposes several explanations in support of substance mind-body dualism, each of which have their own form of merit and novelty––an obvious fact, as Descartes has stood the test of time and been a major source of contentious themes within the philosophical community. However, when taken out of pedagogical philosophy and placed into the context of the everyday, there are some gaps in the development of what follows from dualism and what this means for the ordinary person. In order for Descartes’ dualism argument to be relevant and convincing, there are three components that must successfully be addressed: what, where, and how.

The Sixth Meditation deals with the issue of unity of the distinct mind and body parts. It’s inarguable that, even if established as distinct entities, the mind and body are very closely intertwined––so much so, that for the common man, the dualist phenomenon is one that might never cross their minds. Descartes identifies the what as such: “I (a thinking thing) am not merely in my body as a sailor is in a ship. Rather, I am closely joined to it—intermingled with it, so to speak—so that it and I form a unit.” (Descartes 30). The mind and body, though separate, act as one. The where is approached in a very scientific manner, Descartes utilizing anatomic knowledge to identify a specific place in the brain in which the mind-body interaction takes place. In The Passions of the Soul, Descartes identifies “a certain part of the body where it exercises its functions more particularly than in all the others” (Descartes 9) . The pineal gland, he decides, is the sole place in which the “soul can directly exercise its functions” in one unified location (Descartes 9). In this work, he further elaborates on the idea of “sense-organs”––eyes, hands, ears––within the human anatomy that help bridge the mind-body relationship and translate the external world in a manner perceivable to the mind.

The question of how this relationship occurs, however, is not one that is detailed in either The Meditations on First Philosophy or The Passions of the Soul. As Scott Calef, professor of philosophy at Ohio Wesleyan University best put it, “If the dualist doesn’t know or cannot say how minds and bodies interact, what follows about dualism? Nothing much.” (Calef) This is an issue that cannot be addressed just conceptually, like the what, as that remains too broad and imprecise. Science, a field which only covers structures of the physical world, was apt to answer where, but not enough to explain the full story as, within the diegesis of The Meditations, the mind has been established to have no extension. If anyone should have the ability to figure out the nature of this interaction, it would be Descartes, who in himself professes to be a married reconciliation between both philosophy and science.

It should be acknowledged, though, that it is simply too much to expect an inerrant argument and faultless logic, with every question answered––after all, with such things, there would be no place for philosophy. The Meditations concludes with a call to action from Descartes, stating that we all “must acknowledge the weakness of our nature”, conceding the inherent flaws that preside over us all (Descart 34) . Perhaps there can only be imperfect explanations of existence for imperfect beings.

Sources used:

The Meditations on First Philosophy, edited by Jonathan Bennett: http://www.earlymoderntexts.com/assets/pdfs/descartes1641.pdf
From the Internet Encyclopedia of Philosophy’s entry on Dualism and Mind: http://www.iep.utm.edu/dualism/#SH3c
The Passions of the Soul, edited by Jonathan Bennett: http://www.earlymoderntexts.com/assets/pdfs/descartes1649part1.pdf
Logical argument taken verbatim from source by Purdue University: https://web.ics.purdue.edu/~curd/110WK13.html