1. Doubting Mind-Body Dualism
By: Cassandra Gill

2. Thesis
Descartes argues that the mind is a distinctive thing existing entirely separate from the body; while Descartes argument is very methodical and carefully crafted, his conclusion is not as certain as he believes it to be.

3. Descartes’s Argument
So here is a summary of all the points Descartes makes for dualism:
There is a radical split between the body and mind. Learning belongs exclusively to the mind. The mind is a pure and indivisible, while the body is a composite and divisible; therefore, the mind and the body cannot compose of the same thing. I am a distinct thinking thing; I believe my body is a distinct, non-thinking thing. Therefore, I am a separate from my body and can exist without it. I can doubt that I have a body; I cannot doubt that I am. Therefore, the mind and the body are separate.

4. The Radical Split between the Body and Mind
“ I think, therefore I am” (Descartes 19).
“What else am I? I will set my imagination in motion. I am not that concatenation of members we call the human body. Neither am I even some subtle air infused into these members, nor a wind, nor a fire, nor a vapor, nor a breath, nor anything I devise for myself. For I have thought these things to be nothing” (Descartes 65-66).

5. The Radical Split
Descartes presents us with this idea that there is a huge separation between the mind and the body. There is this sharp contrast between the internal and external world with a gap between them. However, we know that this barrier is not so clear.
Mental events seem to cause physical adaptation.
Excessive thoughts of worrying and dwelling on things could cause your hair to turn gray much more quickly. Look at how aged the presidents look after they ended their term in office. One does not think his hair gray.
In Descartes’s theory of extended and unextended substances, the extended body can send ideas to the unextended mind, but the extended body cannot affect or change the unextended mind.
However, the body does affect the mind.
Drugs affect our mind’s thoughts.
Traumatizing worldly events can completely alter how we think about the world and cause one to see everything negatively.

6. A Radical Split that Cannot Be Reconciled
The mind and body are radically different things. They are so different from one another that it is hard to see how they can interact with each other. Because of his theory of causality, Descartes has no logical answer for how the mind and body could interact.
In his book The Rationalists, John Cottingham writes:
When questioned as to how the soul can be effected by the body and vice versa, given that their natures are so completely different, Descartes is reported to have admitted that this was 'very difficult to explain.' (AT V. 163; CB 28). Unfortunately an explanation, in Cartesian terms, seems not just difficult, but impossible. For the Cartesian model of explanation requires that, if X and Y are causally related, then there must be some intelligible link between X and Y; the cause must be 'like' the effect, or the features found in the effect must be present in some form in the cause. Yet Descartes has to admit that there is no intelligible connection at all. . . (Cottingham 126).

7. The Evolution Problem
“Accordingly, it is this nature that teaches me to avoid things that produce a sensation of pain and to pursue things that produce a sensation of pleasure, and the like. But it does not appear that nature teaches us to conclude anything, besides these things, from these sense perceptions unless the intellect has first conducted its own inquiry regarding things external to us. For it seems to belong exclusively to the mind, and not to the composite of mind and body, to know the truth in these matters” (Descartes 99).

8. The Evolution Problem
If nature teaches us only instinctive things, we would never have been able to thrive in this natural world. Nature taught the human brain to grow and adapt to enhance our abilities to reason. Performing taxing exercises taught our minds to have endurance. Our evolution to become the intelligent human beings we are today is almost entirely attributable to our environment.

9. The Evolution Problem
Nature can teach our bodies to conclude things The body is actually capable of complex learning that occurs below our level of consciousness, outside of our mind.

10. THE DIVISIBILITY/ INDIVISIBILITY ARGUMENT
“. . . we need to realize that body, taken in a general sense, is a substance and hence it too can never perish. But the human body, insofar as it differs from other bodies, is composed of merely a certain configuration of members, together with other accidents of the same sort. But the human mind is not likewise composed of any accidents, but is a pure substance” (Descartes 55).

11. THE DIVISIBILITY/ INDIVISIBILITY ARGUMENT
“. . . there is a great difference between a mind and a body in that a body, by its very nature, is always divisible. On the other hand, the mind is utterly indivisible. For when I consider the mind, that is, myself insofar as I am only a thinking thing, I cannot distinguish any parts within me. . .” (Descartes ).

12. THE DIVISIBILITY/ INDIVISIBILITY ARGUMENT
The mind cannot be considered completely indivisible though.
If we consider the mind to be our ideas and ability to think and reason, brain damage could easily affect these processes. Head trauma could cause us to lose part of our memory. Removing parts of our brain could cause us to think about the world entirely differently with a new personality. The degeneration of our brain cells that occurs with dementia limits people’s mental capacity to think clearly and know who are as a person. If our physical, divisible brain is damaged in certain ways, the mind is diminished in certain ways.

13. THE DIVISIBILITY/ INDIVISIBILITY ARGUMENT
The mind is not one homogeneous substance. There are often conflicting thoughts going on in our mind that can arise from one physical object we interact with.
We are torn between choices all the time such as whether we want to enjoy some cake or not and lose weight; drive fast or be a safe, careful driver. One physical object is sending differing ideas into our mind. However, according to Descartes’s theory of causes, one thing can only be perceived as one idea in our mind. This conflict of thoughts implies that there are separate entities and thinking processes going on within us. Therefore, the mind is not one pure whole, but a set of different parts like the body.

14. CLEAR AND DISTINCT PERCEPTION
“From all this one ought to conclude that all the things we clearly and distinctly conceive as different substances truly are substances that are really distinct from one another. (This, for example, is how mind and body are conceived.)” (Descartes 54).

15. CLEAR AND DISTINCT PERCEPTION
“I judge that obviously nothing else belongs to my nature or essence except that I am a thinking thing, I rightly conclude that my essence consists entirely in my being a thinking thing. And although perhaps (or rather, as I shall soon say, assuredly) I have a body that is very closely joined to me, nevertheless, because on the one hand I have a clear and distinct idea of myself, insofar as I am merely a thinking thing and not an extended thing, and because on the other hand I have a distinct idea of a body, insofar as it is merely an extended thing and not a thinking thing, it is certain that I am really distinct from my body, and can exist without it” (Descartes 96).

16. CLEAR AND DISTINCT PERCEPTION
Let’s break down Descartes’s logic:
1. I am a distinct thinking thing.
2. I believe my body is a distinct, non-thinking thing.
3. Therefore, I am a separate from my body and can exist without it.
So if the basic logic is that if two things are distinct, one could exist without the other.

17. CLEAR AND DISTINCT PERCEPTION
However, the problem lies in the structure. Premise A and premise B does not guarantee the validity of conclusion C.
1. A is a right triangle because a2 + b2 = c2
2. B is distinctly a triangle because it has a 90o angle and its 3 sides = 180o.
3. Therefore, triangle A is distinctively different from triangle B.
These two properties are very distinctive one is talking about sides and ones is talking about angles. According to Descartes, one could exist without the other. However, this is not the case. Even though I see this property as being very different from the other, they are essentially connected.

18. Objection based on Descartes’s own methodology
There’s another objection to Descartes’s concept of “clear and distinct perception.”
We cannot assume to know what is “clear and distinct” unless we know everything about the subject. (This is the very idea that Descartes suggests in order to be able to doubt everything.)
So, we do not truly know if we know everything about the mind. Thus, we do not know that the mind is Not distinctly corporeal. We cannot conclude that the mind as a thinking thing is clearly not ALSO a corporeal thing, unless we know that we know everything about the mind.

19. The Doubt Argument
“Therefore I suppose that everything I see is false. I believe that none of what my deceitful memory represents ever existed. I have no senses whatever. Body, shape, extension, movement, and place are all chimeras. What then will be true?”(Descartes 63)
(Devil Argument) “But still [I] think, so …Then too there is no doubt that I exist, if he is deceiving me” (Descartes 64).

20. The Doubt Argument Let’s break down Descartes’s logic again:
1. I can doubt that I have a body.
2. I cannot doubt that I am.
3. Therefore, I as thinking, intangible thing am not of the same substance as my physical body.
This is the Logical formula of his argument:
1. I cannot doubt the existence of M.
2. I can doubt the existence of B.
3. Therefore, M is not the same as B.

21. The Doubt Argument
Using that same logical formula, we can disprove the validity of his conclusion.
So in another logical example, Lois Lane thinks:
1. I do not doubt that Clark Kent is a journalist.
2. I doubt that Superman is a journalist.
3. Therefore, Clark Kent is not Superman.
But Clark Kent is Superman. There must be something wrong with the argument clearly.

22. Works Cited
Cottingham, John. The Rationalists. Oxford: Oxford UP, Print.
Descartes, Rene. Discourse on Method and Meditations on First Philosophy. 4th ed. Indianapolis: Hackett, Kindle.

23. Discussion Questions
Are there any other flaws you saw in Descartes’s argument?
Do you believe there is a better way to explain mind-body dualism? How would you fix some of the mistakes Descartes made?
How connected do you believe the mind and the body are?