The Mind & Body Problem (04 February 2023; Descartes/Spinoza)

In addressing the mind-body problem, I’ll consider two philosophies in this essay. One of which is Descartes’ answer, mind and body dualism, suggesting that mind and body are substances distinct from one another. I’ll counter Descartes’ dualism with Spinoza’s philosophy of parallelism, in which mind and body are simply attributes of the same substance. First, I’ll provide background information on dualism, explaining how mind and body fit into Descartes's philosophy. Next, I’ll discuss how he ties his arguments together in meditation six, reinstating senses/bodies. These aspects will be done primarily in reference to his work Meditations on First Philosophy (1641). Finally, I’ll address flaws in the dualistic view of how mind and bodies are connected, and counterargue dualism by way of parallelism, explicating dualism’s flaws and how Spinoza answers (primarily referencing Ethics (1677)) what Descartes could not.

    Descartes begins differentiating mind from body in meditation two. To Descartes, mind and body are both substances separate from one another, that do not rely upon one another for their own natures. He understands that bodies are “all is that is capable of being bounded by some shape, of being enclosed in a place, and of filling up a space in such a way as to exclude any other body from it” (M2). This definition adheres to the concept of extended things or any three-dimensional thing that takes up space. This is different from the mind insofar as the mind is not spatially substantial, nor can it be bound by some shape, or meet any of the criteria which the Descartes laid forth for bodies.

    To explore what mind is, his argument can be traced back to that of the evil genius. He doubts the existence of corporeal beings and discounts the senses. If he is deceived in his thinking by an evil genius, there must be something that exists that’s being deceived, so he comes to the conclusion that “‘I am, I exist’ is necessarily true every time I utter it or conceive it in my head” (M2). Given certainty of his existence, he questions what the essence of himself (“I”) is. To do so, he ponders what would happen were he to cease existence; he has certain knowledge that thought exists, and thought cannot be separated from himself. If he were to cease thinking, he would cease to exist. He deduces, “I am therefore precisely nothing but a thinking thing; that is, a mind, or intellect, or understanding, or reason” (M2). Descartes has now reached the distinction that he is most certainly, at the least, a mind, a thinking thing. To clarify what it means to be a thinking thing, he claims that it’s a thing that “doubts, understands, affirms, denies, wills, refuses, and also imagines and senses” (M2).

Armed with the knowledge of being a thinking thing, we must now turn our attention towards the role of extended things, and their relation to the mind. To Descartes, the mind is totally immaterial, and corporeal things are simply revealed to the mind by means of the senses. We have ideas about these corporeal things, and ideas that resemble bodies, but these ideas are distinct from bodies. As a thinking thing, Descartes's existence evidently “does not depend upon things whose existence I do not yet know” (M2). In “things whose existence I do not yet know,” Descartes is referring to things ascertained by the senses, bodies, which fall under the category of extension. Those things which he is aware of through the senses were discredited at the outset of meditation two in order to find certain truths about the mind and the body. As he is independent of those things which he does not know (bodies), it is clear that mind itself is separate from bodies. Descartes then turns his attention towards the senses: Because he may be asleep, he discounts the notion that his senses are providing him accurate information of the bodies around him. However, he does know that his senses are indeed sensing; thus, sensing is not a faculty of bodies, but rather a faculty of the mind (he later changes this view). This is important, because although it is a part of the mind, it is separate from reason and judgment. The nature of the beeswax proves this, in that although the senses perceive the wax to have changed form from its original state to a completely different thing, it still remains wax; thusly, “bodies are not, properly speaking, perceived by the senses or by the faculty of imagination, but by the intellect alone” (M2). While the senses provide raw data to the mind, they cannot be trusted, and it is the responsibility of intellect to come to the conclusion that the wax is still wax. If those senses that observe extended things were stripped of him, his mind would still produce thought, as he is a thinking thing; thus, he (mind) is distinct from what exists beyond his mind (bodies).

Descartes' clearest and most precise distinction between mind and body occurs in meditation three. He says that what’s clear and distinct of corporeal things is their “substance, duration, number, and whatever else there may be of this type… I think that a stone is a substance, that is to say, a thing that is suitable for existing in itself; and likewise I think that I too am a substance” (M3). With the knowledge that he himself, along with extended things, are both substances, he goes on to explain the difference between the two: 

“I conceive myself to be a thinking thing and not an extended thing, whereas I conceive 

of a stone as an extended thing and not a thinking thing, and hence the greatest diversity 

between these two concepts, nevertheless they seem to agree with one another when 

considered under the rubric of substance… none of the corporeal things are fashioned are 

contained in me formally, since I am merely a thinking thing. But since these are only 

certain modes of a substance, whereas I am a substance, it seems possible that they are 

contained in me eminently” (M3).

While both are substances, Descartes is a thinking thing, and a stone is an extended thing, and these definitions are not interchangeable. Corporeal things, including his own body, are not within himself, formally (a thinking thing). Because corporeal things are only modes of substance, and he is wholly a substance, those things have less perfection than their ideas contained within himself have.

In meditation six, he begins his discourse with the statement that material things “can exist, at least insofar as they are the object of pure mathematics, since I clearly and distinctly perceive them” (M6). Since they can exist, he endeavors to answer whether or not they actually do exist. For this, he references imagination, previously known as a faculty of the mind. Imagination is “a certain application of the knowing faculty to a body intimately present to it, and which therefore exists” (M6). Descartes realizes that in order to use the faculty of imagination, it follows that there should be something divisible from himself, a thinking thing, which narrows down to extended things. If mind and body were unionized, it makes sense that the means of the body (in this case, sensing) could lead to the imagination of corporeal things. The senses are different from intellect in that the mind's understanding depends upon looking over itself and its own ideas, but when the mind imagines, “it turns toward the body, and intuits in the body something that conforms to an idea either understood by the mind or perceived by sense” (M6). Since Descartes can think of no other way in which the imagination faculty could function, he determines that a body indeed exists. He also has a clear and distinct understanding that one thing can exist without another, meaning its possible for mind and body to be separated from each other; he has a body that is joined to his mind, alongside a clear and distinct idea that he is a thinking thing and body is an extended thing, therefore he is distinct from his body as he can exist without it.

Ideas perceived by sense are more vivid than those found in understanding, and those ideas could not have come from himself (as senses pertain to bodies). Because he can understand himself clearly and distinctly without those senses, but mind is indivisible, sensing must be a mode of a thing (which is his body). Sensing is in a different substance than himself, as he is a thinking thing; he narrows their belonging to god, an extended thing, or some other creature. Because

“god has given my no faculty whatsoever for making this determination, but instead has 

given me a great inclination to believe that these ideas issue from corporeal things, I fail 

to see how god could be understood not to be a deceiver, if these ideas were to issue from 

a source other than corporeal ideas. And consequently corporeal things exist” (M6).

Descartes' understanding of the senses as being of corporeal things (and that corporeal things exist) is foundational to an understanding of what Descartes concludes about senses. Later in the meditation, he mentions that the sick man, whose consumption of water would worsen his condition, still has a sensual perception of a dry throat and an inclination to drink. While God is certainly not a deceiver, humans are imperfect, and our senses are frequently confused and unclear. Thus, it is the mind that can bridge the gap and aid in our survival: through use of cognition, “connecting current happenings with past ones, and intellect to examine causes of error,” we can oftentimes notice when the senses are wrong in their perceptions, and it is this which leads Descartes to be alleviated of his fears of those senses which deceive us daily.

As to the union of the mind and body, Descartes knows corporeal things exists, senses are real and attributable to the body, and can be trusted (most of the time). Our having a body that experiences pain and senses, demonstrates that we do indeed have some sort of body. Descartes describes the connection of mind and body in that they don’t merely coexist near each other, but are more unionized than that (while still being distinct). He claims that his body and himself “constitute one single thing,” as if they were commingled. The senses, which can be attributed to bodies, reach the mind through this union, such as when you see things, feel pain, or get thirsty. Descartes claims that this commingling is made possible through a part of the brain called the pineal gland, which he references in other works. So, Descartes’ dualism is no more complex than a mind and body, of different substances, distinct from one another, commingled in a human being. This, however, does present one obvious issue.

If mind and body are of different substances, one being material and one immaterial, both entirely distinct from one another, how could the mind interact with the corporeal world? Descartes' explanation of the pineal gland being the translator of the senses is a weak argument, in that it does not fully explain how the gap between the two distinct substances is bridged. Spinoza, however, offers a viable alternative to this. In his Ethics, he claims that “If things have nothing in common with one another, one of them cannot cause any effect in the other” (i:P3[P2,A4,A5]), which is in direct contradiction to what dualism would argue. Dualistic philosophy would argue that two things with nothing in common (mind and body) can indeed cause effect in another; yet he doesn’t seem to be able to establish that link in his philosophy. Spinoza furthers this argument, stating, “things that have nothing in common cannot be explained through one another, or, the concept of the one does not involve the concept of the other” (i:A5), which can also be applied in counterargument to dualism. 

In Spinoza’s philosophy, God/Nature is the generator of/contains within itself everything in the universe, one substance. Thought, or mind, is an attribute of this substance, just as extension, or body, is an attribute of the same substance. There are infinite attributes of substance, but thought and extension are the only two which we can conceive. A specific body, such as the human body, is a mode under a specific substance. Under the philosophy of parallelism, there need not be a connection between the mind and body; bodies in close contact, there is an unvarying relation in movement in speed. The mind has a conatus, or natural impulse, which seeks what assists in and resists what opposes it (this is otherwise known as will), and when actions of the mind and body happen to correspond together in what are called appetites. The connection of ideas is the same as the connection of bodies, that is, they are both of the same substance. Because everything is just a different essence of the various attributes of the same substance (key being different reflections of the same thing), they all operate in parallel. Of mind, Spionza describes it as being a part of the intellect of god, and is also a thinking thing: “the human mind, that is, insofar as [God] constitutes the idea of the human mind, that is, insofar as he constitutes the essence of the human mind– has this or that idea” (i:P11).

Though Descartes’ philosophy offers a certainly convincing set of arguments about mind, body, and the senses, his dualism failed at the crucial linking between two distinct things. Spinoza’s philosophy of parallelism is a sufficient counter to these flaws, as the mind and body need not interact for humans to function. Through his discourses, it can be concluded that even though we may think our mind and body interact, it is indeed impossible for them to do so given the differences between the two.