Does Descartes Succeed in Explaining how Mind and Body Interact?

Nick Fletcher

PH100

Does Descartes Succeed in Explaining how Mind and Body Interact?

The enlightenment was an attempt to replace the faith truths of religion and traditional beliefs with scientific knowledge and reason, as people had become disillusioned with both the ruling aristocracies and the church, especially in Europe and America. They began to question the previously absolute power that these institutions held, and soon began to realize that where there had been certainty there was really only ignorant faith. In this age of uncertainty, Philosophers and laymen alike sought to determine whether mankind could have knowledge at all, and much of this enquiry began with thinking about the human mind. Descartes was one of the pioneers of the age of enlightenment; his method of doubt now provides a paradigm example of the sentiment of the age. As with any pioneering philosophy, philosophy, Descartes made great headway into modern thinking about the mind/body union. Whilst he was unable to s atisfactorily atisfactorily explain how the mind and body interacted his work served to provide a starting point from which research and debate on the subject could begin in earnest. The immaterialist theory of mind stems from Descartes’ famous Cogito argument. Descartes hoped to discover via his method of pure enquiry indubitable facts he could use as a starting point for his metaphysics. However, However, through his method, he was able only to be sure of the existence of his own intellect, as in the process of doubting the existence of his mind he proved its existence; ‘cogito ergo sum’. The existence existence of anything else could be doubted as reality could well be a highly realistic dream, or reality could be some demon deceiving us. Thus Descartes established his own existence as a thinking thing, or res cogitans to use the Latin term; as the res cogitans was the only thing that could not be doubted it must be distinct and separate from everything else that could, most importantly the body. Just as the mind is defined in the Meditations as res cogitans, thinking substance, matter is defined by Descartes in the Principles of Philosophy as res extensa, extended substance (Cottingham, 1988). Descartes is able to reduce matter to nothing more than ‘dimensionality’ or ‘spreadoutness’ (Cottingham, 1988). Matter is simply that which occupies space; in this Descartes argues that the concepts of space and the concept of a corporeal substance substance are not distinct. He is able to do this by considering the idea of a stone and ignoring any feature of the stone that was non-essential to the nature of the stone (AT (AT VIII. 46; CSM I. 227). He ignores the concept of hardness, as the stone can be melted or pulverized causing it to lose its hardness without ceasing to  be a body. He ignores the concept of colour, as diamonds do not have colour and they are examples of stones. He ignores the concept of weight, arguing that whilst fire is extremely light it is still a corporeal substance. Finally he ignores the concepts of cold, heat and all other such qualities as these may affect the stone, but do not cause it to lose its bodily nature. All that is left after this stripping down of properties are the concepts of  length, breadth and depth, or simply the concept of volume. When matter is considered in this way, as just geometrical geometrical space, there is no way that a complex property such as consciousness could be ascribed to it. Having defined res cogitans and res extensa, Descartes could go on to try and explain how the two interact. He began by showing how these two seemingly incompatible incompatible substances could be brought together to

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Nick Fletcher

PH100

form a single person. To avoid doubt, he analyzed the ideas he found within his own consciousness, starting with the entity that created man, God. Descartes believed that God is a substance that is infinite, eternal, immutable, independent, omniscient, omnipotent and the creator of all things (AT VII. 28; CSM II. 19). Descartes ‘proves’ the existence of God by first arguing that ‘there is nothing in the effect that was not  previously presented either in a similar or higher form in the cause’ (AT VII. 135; CSM II. 97); then Descartes applied this causal adequacy principle to ideas in his mind, particularly their representational context: their  objective reality. Essentially, Descartes believed that the perfections present in his own idea of God must be  present in what caused the idea. Descartes himself could not have been the cause of these ideas, as, for  example, he himself was finite, yet he still had the idea of an infinite substance. Therefore the ideas must have come from something else, importantly something else that did have those properties. As the idea of an infinite substance existed in Descartes mind, it necessarily exists in reality, reality, as the idea of God existed in Descartes mind, God, as Descartes perceived it, must exist in reality. 1 From his claim of a perfect God comes Descartes ‘argument from clear and distinct perception’, the principle argument behind the counterintuitive claim that there is a real distinction between mind and body. Descartes argued that because he was able to conceive the mind and the body existing separately, then they must be able to and as such are distinct, separable entities. However, he writes elsewhere that the mind is ‘intimately ‘intimately conjoined and intermingled with the body’ (AT VII. 81; CSM II. 56). He argues that the mind and body must be more closely mingled than a sailor controlling a ship, as the sailor perceives damage to the ship via remote  perception. Feelings Feelings such as hunger, thirst and pain cannot be perceived by pure intellect, as this would give the  perceiver an explicit understanding of the problems that cause the sensation. Feelings, rather than explicit  perceptions of bodily states, are confused ideas of bodily states; Descartes believed that this confusion arose from the commingling of mind and body. The mind could not perceive the state of the body via remote  perception, nor could the mind directly perceive the state of the body by virtue of them being one and the same entity. entity. Thus Descartes is able to use both the counterintuitive claim that the mind and body are separate entities capable of separate existence and the intuitive claim that they are closely intermingled to develop his explanation of how the mind and body interact. However, the idea of the immateriality of the mind posed many problems for Descartes. Firstly, one could go on forever arguing that the body and mind are completely distinct entities, but everyday experience serves as proof that people are very much embodied beings. Descartes could not explain this embodiment by arguing that the mind is in some way diffused throughout the body, as this would imply extension which his

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 It must be noted here that Descartes had overlooked the possibility of his idea of an infinite substance could simply

have come from his idea of a finite substance. To use another example, if I encounter an object that is rough, I would be able to  postulate the existence of an object that is not rough, an object that is smooth, without having to encounter such an object.  Descartes had encountered an object that was finite, himself; as such he was able to postulate the idea of something that was not   finite, an infinite object, God, without having to encounter such an object.

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Nick Fletcher

PH100

theory of mind will not allow. Instead, Descartes postulated a physiological argument that the mind acts on the  body via the pineal gland in the brain. He chose the pineal gland as he believed correctly from intuition that the mind is centered in the brain, and because he believed incorrectly that only human beings had pineal glands, that animals possessed neither minds nor pineal glands. Also, Descartes observed that the pineal gland was situated in the middle of the brain, and was suspended above a passage through which he believed the spirits in the brains anterior cavities communicate communicate with

those in its posterior cavities (Cottingham, 1988). He believed that movements of the pineal gland would release ‘animal spirits’ that would travel down the nerves as a sort of fine gas and activate the muscles of the  body.  body. He believed that these spirits moved through the nerves as he observed that sensation was always created  by movement. Pain can be caused by a knife moving against the skin, a bang on the head can cause a person to see stars and stopping up a person’s person’s ear causes him to hear murmuring (Kenny, (Kenny, 1968). Descartes had theorized a broadly correct view of the function of the nervous system, and whilst the details of the theory may be fanciful, the basics of it are true of the modern electro-chemical electro-chemical account of nervous function. However, by  postulating that the pineal gland was the ‘seat of the soul’ Descartes had not even begun to theorize how res cogitans was able to act upon res extensa, how these two wholly alien substances interacted; he had merely sidestepped the question. Unfortunately, Unfortunately, a Cartesian explanation explanation of how these two substances interact appears impossible (Cottingham, 1988). One of the arguments central central to Descartes proof of a perfect God mentioned above, above, that ‘there is nothing in the effect that was not previously presented either in a similar or higher form in the cause’ (AT VII. 135; CSM II. 97) would mean that there must be some similarity between the res cogitans and the res extensa in order for them to interact. However, as res cogitans is pure thought and res extensa is pure shape there can surely be no similarities between the two. According to the Cartesian model that spawned the ideas the two substances cannot interact. Faced with this insurmountable ontological problem, Descartes postulated that it is God that allows the two to interact; ‘God could have made the nature of man such that this particular  motion of the brain indicated something else to the mind’ (AT VII. 88; CSM II. 60), as though God provided some kind of divine dictionary that acted as a translator between mind and matter. Descartes view that the mind is a non-physical entity has been a controversial one ever since the time of its conception. A contemporary contemporary of Descartes, Gassendi, believed that the immaterialist theory of the mind had been asserted without proof and wrote to Descartes that ‘the onus is on you [Descartes] to prove that you are unextended an incorporeal’ (cited by Cottingham, 1988 pp116). In the Fourth Set of Objections (1641) Arnauld, another contemporary of Descartes, gives his geometrical counterargument counterargument (Cottingham, 1988), whereby someone who does not know the P ythagorean ythagorean rule that the square of the hypotenuse of a right angles triangle equals the sum of the squares of the other two sides could envisage a triangle where the rule does not apply, apply, and even perhaps suppose that such a triangle could be constructed. This shows that just because someone can conceive of X without Y (the triangle without the Pythagorean property) does not prove that Y is

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Nick Fletcher

PH100

not essential to X’s nature. To determine what is essential to X’s nature may well require much more investigation investigation than simple conception. This seemingly unanswerable counterargument removes the very foundations of Descartes argument for the immaterial mind. Descartes himself believed believed that philosophizing was not the best way to determine how the mind and  body interact. In a letter to Queen Elizabeth he argues that the union between the mind and body could be better   perceived by sense rather than intellect (Kenny, 1968). Elizabeth herself had argued that it was easier to matter  and extension to the mind than it was to attribute the ability to move matter and be moved by matter to an immaterial mind. Descartes reply to this was disappointing; that it was fine to attribute matter to the immaterial immaterial mind as that was to conceive that the two were united. However, extension could not be an attribute of the mind as, by Descartes own definition, extension is divisible and the mind indivisible. Also, the existence of extended substance requires it to fill a space in the physical plain and exclude any other extended substance from that  place, the extension of thought does not. A more modern objection to the Cartesian mind/body dualism describes it as ‘Descartes error’ (Damasio, 1994). The term, coined by Damasio, stems from his physiological study of people with certain types of brain damage. Damasio studied the case of Phineas Gage, a man who had an accident that damaged the  part of his brain that enabled him to fee emotion. He demonstrated that whilst Gage’s intellect had remained undamaged after the accident, accident, his ability to reason had been significantly reduced as he was no longer able to use his emotions in the process. Using the example of Gage amongst others, Damasio had shown that not only was the mind divisible, but also that the state of the mind was a refection of the state of the body and therefore the two were not as distinct and separate as Descartes believed. Another common argument against dualism is the idea that since human beings began their existence as entirely physical or material entities and as nothing outside of the domain of the physical is added later on in the course of development, development, then we must necessarily end up being fully developed material beings. The human species evolved, as did all other species, from a single cell made up of matter. Since all the events that led to the formation of our species can be explained through the processes of random mutation and natural selection, it is difficult to determine when and why some non-material, non-material, non-physical event could have intervened in this  process of natural evolution. Had Descartes been presented with this argument he would have most probably argued that it was God who intervened, but this is smacks of aporia. Finally, there are many philosophers who would argue that the Cartesian mind/body dualism is ontologically ontologically extravagant. The idea of Okhams Razor is that all things being equal, the simplest solution tends to be the best one. In other words, when several competing theories are equal in all other respects, the theory that has the fewest assumptions and postulates the fewest ontological entities is the best one. This sentiment is found in all other sciences, under the guise of parsimony. parsimony. It would be difficult for Descartes to show why it is necessary to postulate two distinct ontological entities, the mind and the body, when other thesis exist that  provide a simpler explanation.

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Nick Fletcher

PH100

It is clear that Descartes was unable to satisfactorily satisfactorily explain how the mind and body interact. His  philosophy,  philosophy, whilst immensely important historically and truly beautiful, is highly flawed. Descartes unshakable faith in the perfect God, the God that would not deceive him is the source of these flaws. Faced with an inability to believe anything except except the cogito, Descartes would have been in danger of losing his faith in the God that he loved; how could the Christian God, the God of revelation and love, create a world in which nothing could be certain, except the lonely existence of ones own intellect? intellect? Thus, Descartes made an ontological leap of faith using his causal adequacy principle to ‘prove’ that that his God existed. It is on this highly dubitable principle principle that the rest of Descartes explanation explanation of how the mind and body interact is based. The parts of Descartes explanation that concerned the physical aspect of the mind/body interaction are remarkably similar  to the scientific explanations explanations of modern times. Descartes was able to postulate the existence of a nervous system controlled by the brain, and backed up his theory with scientific evidenc evidencee such as the phenomenon of   phantom limbs. It is when Descartes tries to explain the nonphysical part of the mind/body interact interaction ion that his ideas lose their foundation. However, whilst modern science has been able to determine the exact chemical  processes that produce thoughts and feelings, we are by no means closer to determining how these chemical  processes produce consciousness. To To conclude, Descartes was able to produce a surprisingly scientifically scientifically valid explanation of the physical side of the mind/body interaction, he was unable to postulate a convincing explanation of the spiritual side, but nor has any philosopher, philosopher, scientist or religious figure since.

References: Damasio, A.(1994). Descartes' Error: Emotion, Reason, and the Human Brain. Cottingham, J. (1988). The Rationalists. Rationalists. Kenny, A. (1968). Descartes, a Study of his Philosophy. Philosophy.

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