By, Fotios Bassayiannis (1997)
Like Plato among the ancients, Descartes among the moderns can be considered a “Caput Nili” of the philosophical study of the nature of man. Although his scholastic background introduced him to the time’s prominent view of the nature of a person[1], he soon realized that the philosophical speculative method used on this matter needed a profound restructuring. Specifically he argued that for any philosophical progress to be made the first thing that had to be done was to set up an indubitable basis of necessary facts[2] on which all subsequent contingent facts would be based by means of a rigorous geometric method. He finds his indubitable fact in the “cogito”[3] and from there on he attempts to reconstruct an indubitable, secure view of what exists.[4] His next step is to demonstrate the existence of God[5] and from there the existence of the material world.
The very nature of Descartes’ method of constructing his metaphysical system inherently suggests a kind of dualism.[6]In fact the root of Descartes’ mind-body distinction lies in his initial argument that because the existence of that which thinks[7] can be proven without having proven the existence of that which extends[8], then the mind must be logically distinct from the body.
Summarizing his method, one can say that his dualistic view of the world emerges in three distinct and geometrically structured steps:
1. He affirms the existence of the “Res Cogitans” based on the certainty of his own thought.
2. He concludes the existence of the standard of perfection[9] apart from his mind, based on the certainty of the imperfection of his own thinking.[10]
3. He proves the existence of external bodies (not just human) based on the certainty of God’s perfection.[11]
It is important here to focus for a while on Descartes’ effort to establish a physical world. In his attempt to reach the corporeal by means of the incorporeal he is actually faced with a “reverse-transcendence” problem.[12] Specifically in the first person case, being is seeming and seeming is being while in an objective (and not anymore subjective) world[13] there is a potential divergence between being and seeming. As we saw Descartes takes care of this problem with his arguments about the existence of a perfect God.
Once Descartes made his body-mind distinction he proceeded to describe with as much clarity as possible the characteristics of each.
Specifically he described mind as being:
1. Thinking.[14]
2. Indivisible.
3. Unextended.
while the body is described as being:
1. Non-thinking.
2. Divisible.
3. Extended.
Scholastics maintained that mind is indissolubly linked to flesh which is intrinsically weak. In so doing they rendered the mind to be also weak. Descartes, on the other hand, argued that the mind is excellent and makes up for the deficiencies of the body to a very high degree.[15]
In fact his whole theory of knowledge is based on this doctrine. Specifically, in his description of the mind, he distinguishes between two[16] faculties: a purely intellectual one[17] and a second one of a “sensuous” nature which is dependent on the first.[18] In this setup the intellectual faculty provides the understanding through the operation of unification of “sensuous” impressions and also rules out possible erroneous[19] interpretations of raw sensory data.[20]
In his writings Descartes specifically states that the knowledge of the external world is gained by cooperation of both these faculties. External realities are explored through the joined effort of intellect and senses, but the unity of objects is grasped by the intellect alone and not the senses. In fact, without the intellect the senses are incapable of any kind of secure knowledge. So, in Descartes view only the mind is capable of knowledge and thus understanding. Intelligible things are grasped by the “natural light” of reason alone and “sensible” things are grasped by the smart filtering and unifying of “sensible” experience by reason.
In his description of the body Descartes adopts a purely mechanistic view of its nature; a view which is in accordance with the time’s contemporary scientific developments. The scientific revolution already present in Descartes’ time is very successful in providing very convincing mechanistic explanations of biological systems and it is this exciting trend that leads Descartes to the conclusion that plants and animals are actually “automata”.[21]
This same trend also leads Descartes to use in his descriptions of the body a comparison of it with clockwork. In this model he allows the possibility of body’s direction by mind but he also talks about unconscious bodily functions that are based and directed by the body’s innate faculty of “volition”.[22] This way physiological characteristics of the body[23] that could not really be explained by teleological principles (as the soul) are included in a mechanistic explanatory scheme of the body.[24]
As it is mentioned above, the very definition of Descartes philosophical method involves the concept of dualism. This mind-body distinction that he makes, although it fits in neatly with his scholastic background, the idea that we (as conscious beings) have immediate access to a qualitatively distinct inner realm of experience[25] and his time’s scientific evidence, it also creates a very big philosophical problem. Namely the mind-body interaction problem, mainly in its causational expression.
Descartes, in describing the relation between mind and body, compares it with that of a pilot and a ship. In this kind of relation, the pilot understands (i.e. perceives and knows) the damage that may occur to his ship. Respectively, the mind understands but also senses the actual state of the body. So, one may conclude here that the mind-body relation is considered by Descartes as analogous but kind of more intimate than that of the ship-captain.
In Descartes days, the scientific evidence suggested that if there was a place where body and mind interacted, it was the nervous system. Descartes also noticed that for mental effects there were definite predictable physiological analogues. As a result he accepted that the nervous system was the apparent connection between them and he consequently placed the mind in the brain’s “pineal gland” where , as he said, it resides receiving sensuous impressions and directing movements of the body.
Although Descartes tried to form some kind of theory about the mind-body interaction, it is fair to say that his descriptions about it remain obscure and basically philosophically and even logically unacceptable. Of course this is expected to some extend, since the Cartesian dualism brings up some problems which are indeed very difficult to resolve and which are still today under strenuous and exciting debate.
The main negative asset that the Cartesian dualistic principle involves is the absolute separateness of the two basic categories[26], which makes the mind-body interaction basically impossible. Now, the way that Descartes describes body and mind creates a series of philosophical difficulties which can be summed up in the form of the following two questions: If body must act according to its own laws (concept of “volition”), what part is really left for the mind to play ? And, how can the mind be unaffected by the natural laws that govern the body when it exists in such an intimate and close connection with it?
Although it is hard to answer these questions one is also forced to admit that they really do not constitute a reason to assume that there can be no interaction between body and mind. Still, though it is a great challenge for one to present a theory which is philosophically sound.
Leibniz tried to do so by ingeniously theorizing that the alleged mind-body interaction is only apparent. In fact, he argued that they do not really interact but they appear to do so because mind and body are set up as parallel sequences of events that are harmoniously preordained by the God-Creator.[27] The obvious advantage of this theory is that it accounts for the reality of psycho-physical interrelation while completely abolishing interaction between body and mind. Its main disadvantage is that it raises the matters of whether human beings have free-will and whether people can in fact interfere and restructure the material world according to their mind’s will or intention.
Descartes’ concept of body-mind interaction was heavily criticized by Gilbert Ryle.[28] According to Ryle, Descartes’ psycho-physical dualism has had a much more profound effect on the beliefs of the modern or contemporary world than one would think possible, considering the absurdity of some of the ideas that it involves. This effect is mainly demonstrated in the widespread and generally accepted doctrine that every person has a mind and a body or is anyhow some union or combination of the two[29]. The doctrine also involves the concept that the body exists in physical space and is subject to the mechanical laws which characterize it while mind does not exist in space and is not subject to the natural-mechanical laws.
For Ryle, the way Descartes describes the interaction between body and mind[30] involves many theoretical difficulties; the main of which is a gross “category-mistake”. The origin of this mistake is, according to Ryle, the inexplicable refusion of Descartes to further reduce the mental to the physical, by including the mind in the mechanistic model of the world. So, although this model made perfect sense for everything else (including animals), Descartes argued that the presumed non-mechanical processes that go on in the mind should be explored and explained by another, non-natural, science such as Psychology.[31] This limited reductionist attitude may be explained by the - maybe more than one would think - deep rooted scholastic beliefs in Descartes and the generally too far-fetched notion (for the time of Descartes , that is) that the mind is actually an elaborate biological machine.
The category mistake Ryle talks about, involves the assumption that mind and body exist in the same “sort of way” or mode. In fact, one may start getting the idea that they do not when he considers that all mentallistic terms involve dispositional properties while this is clearly not the case with physicallistic terms which also include non-dispositional properties.
Descartes difficulty in relating or finding the way the mental world interacts with the physical one, is mainly due to the primitive causality model used by him in his quest. This model is based on push-pull interaction which is an extension of a physical law that is invalidly - illogically if you like - expected by him to also work in mind’s realm. For how can this particular model work when Descartes maintains that body is extended while mind is not. Here the “category mistake” that Gilbert Ryle talks about is pretty obvious.[32]
Although it is argued here that Descartes should have had completed his reductionistic process by explaining mind in terms of the physical (and in fact maybe in his time he would have been better off this way) it is not clear in recent years if he really was wrong in so doing.
In the 18th and 19th century growing evidence suggested that the mechanistic view of the human mind was correct. The successful supply of models in biology from mechanical devices on one hand, and the elevation of the nervous system to a key position in describing various psychological processes on the other , helped in that direction. Resultantly, mind was regarded as an object of physiological research rather than introspection[33] and philosophical inquiry. Consequently 19th century psychology started to form a physiological basis and reflexes were the main concern of related scientific research.
As soon as the mid-18th century J. de LaMettrie took what he regarded the logical next step from Descartes’ philosophy; he denied soul to humans too. Leibniz on the other hand argued that the understanding of the form of reason necessarily precedes reference to a possible physical world. Therefore the mind is known without mediation and its study should logically precede the study of the “mediately” known physical realm.[34]
Later Alexander Bain first proposed that sensory-motor activities formed the basis of all higher mental operations. This and the great progress in neurology in 19th century, formed the time’s dominant view that the mental functions could be portrayed as a product of brain organization without involving the researcher in metaphysics. Consequently neuroscientists began to correlate psychological processes with localized parts of the brain.
This kind of attitude supported the idea that progress in the human sciences depended on the reduction of mental to physical explanations. The mainly materialistic dominant views of the time, involved many philosophical problems. The main one of them was that of consciousness and awareness. As a result the theory of psycho-physical parallelism[35] gained in popularity as it left the question of awareness open for discussion.
It is important to mention at this point another important scientific theory of the time that also seemed to support the mechanistic-materialistic trend of the time. The evolution of the species theory[36] by Darwin, kind of clashes with Descartes’ opinion that the human mind exists apart from the rest of the mechanistic world. If the human mind is seen as continuous with nature (more specifically as having been evolved from it) then the Cartesian distinction between body and mind does not hold anymore and if it does then at least one has to grand mind or soul (at least a part of it; but then again is soul dividable or even classifiable into distinct classes ?) to animals too, since according to Darwin’s theory man is the descendant of animals.[37]
Descartes always maintained his position that science cannot access mind. Another philosophical genius (Leibniz) agreed with him. Today, after centuries of philosophical speculation have passed, philosophers generally agree that empirical science cannot resolve the nature of the mind and body relation, for such a relation involves the meaning and clarity of the conceptual categories of science.
As I mentioned before contemporary A.I.[38] and Cybernetics may be related with a meaningful and philosophically robust complete explanation of human beings. Descartes’ sensuous faculty of the mind, his completely mechanistic description of animals and plants and his theory of knowledge (as I have presented it before) certainly do seem to have a common conceptual pattern with contemporary A.I.
A.I. is the name given to the whole field of endeavor associated with producing behavior, which would normally be considered intelligent if displayed by humans, in machines. In this short definition of A.I. one can notice the important concept of “intelligence” being introduced; but, what is intelligence ? Well, this question represents a major philosophical problem. A functionalistic approach (adopted by A.I.) to answering this question is that we may not know for sure what exactly intelligence is but we can certainly distinguish some of its basic aspects, as:
1. Capacity to plan.
2. Capacity to learn.
3. Capacity to solve problems.
4. Capacity to use natural language.
Now the big issue here is: can computers demonstrate behavior bearing any or all of these characteristics ? The answer is that in a limited way, YES ! The way this intelligent behavior is demonstrated is limited because many A.I. problems have turned out to be more difficult than originally envisaged.
A more straight-forward way to define intelligence, was proposed by Alan Turing[39]in 1950[40] in the form of a test that has since been called the “Turing Test”. The test in short, has to do with the proposal that if a human judge, communicating using natural language with another human and a machine by means of a neutral device (such as a keyboard) and being physically separated by both, cannot distinguish who is the human and who is the machine then the machine is in fact intelligent.[41]
Of course the issue that is raised here is the following: What if all other human beings except yourself are just intelligent machines with no awareness or self-consciousness ? How could you, based on Descartes’ philosophical method, really establish the existence of other intelligent beings exactly like you. To say the least, the concept of Cartesian mind in this case becomes rather fuzzy.
Criticism on the Turing Test is based on the fact that the test ignores what is occurring inside the machine, focusing only on the single aspect of the machine’s behavior. It is obvious here that the functionalistic basis of the Turing test is in antithesis with modern phenomenalistic trends. The main concept involved in the opposition to such functionalistic views of intelligence is the concept of understanding.[42]
Then again, A.I. acknowledges that understanding is a major aspect of intelligence and in turn defines understanding, again utilizing a functionalistic pattern, as the ability to interpret information in the light of a body of knowledge which is already possessed. One can notice here the common way A.I. and Descartes define understanding on the basis of knowledge, while A.I. works in a functionalistic-materialistic context and Descartes uses introspection, his concept of mind and the “natural[43] light” of reason.
While the “Port-Royal” Logic defines a term’s meaning by means of Intention[44] and Extension[45], contemporary A.I. defines it by means of Condition and Action, and the philosophical battle, about self-awareness being somewhere in the middle, rages.
According to A.I. adherents knowledge is basically a model of the world as a person perceives it.[46] Specifically this model consists of :
1. Information about existing objects (concrete and abstract).
2. Attributes about these objects.
3. Relationships between them.
Now, some part of this model may be inherited but it seems (overwhelming evidence suggests) that most of it is acquired through experience.[47]If this is the case then learning can be defined in terms of additions and modifications to a person’s model of the world.
Of course the next question that comes to mind is: Can the representation of knowledge in human minds be emulated in contemporary computers ? The approach that most computer scientists adopt to this question is that of a representation of knowledge in relation with utility. This means that knowledge is considered valuable only if it is used for something. Then it is only logical to assume that knowledge can be represented in a way that indicates the ways knowledge can be used. So, each item of knowledge is represented by a “rule” which specifies when to use it and how to use it. Naturally for the “knowledge emulation” to be complete, two more faculties have to be included:
1. A working(short-term in Psychology) memory that contains the current state of the world (model) and which is continuously updated if needed.
2. Learning which must be incorporated in the form of the ability to extend the existing set of rules (actually extend knowledge).
Although the theory is promising the practical results are indeed poor, mainly because of major (and for the time being infeasible) computer hardware limitations.
The Mind-Body problem is indeed a very exciting one. Whatever the correct approach to it may be (that is if there is one), let’s just hope that the one we choose will be prosperous and rewarding.
Bibliography:
Scruton, R., A short history of Modern Philosophy, London 1984, pp. 50 - 79.
Earle, W.J., Introduction to Philosophy, New York 1992, pp. 108 - 116.
Luce, J.V., An Introduction to Greek Philosophy, London 1992, pp. 119 - 120.
Articles from: The Encyclopedia of Philosophy, by Edwards, P.
Articles from: Oxford Dictionary of Philosophy, Oxford 1996.
[1] According to scholastics the person is a created spiritual substance, obscurely related to a body and the world of matter, rational, active, free and immortal.
[2] “Indubitandums”
[3] That is the self-verifying nature of his own thinking.
[4] This actually constitutes his method in answering questions of metaphysical nature.
[5] Actually a step of great methodological importance.
[6] What was later called “psycho-physical dualism”.
[7] “Res Cogitans”
[8] “Res Extensa”, meaning the body.
[9] God
[10] Actually here we have the first demonstration of his “first person privilege”.
[11] Specifically he argues that since God is perfect he cannot be a deceiver. An argument which actually dismisses his initial hypothesis about the existence of an “evil genius”.
[12] In ancient philosophy the usual case is a transcendence from the corporeal to the incorporeal. In Descartes’ method the first step is what we now call “introspection” and as a result the corporeal has to follow from the incorporeal.
[13] Namely the material world.
[14] Descartes’ constant conviction is that all knowledge both begins and ends with acts of the intellect. That is why the “thinking” quality of the mind also implies it’s capability of knowledge.
[15] He actually argues that the body’s nature is such that it liberates it from all deficiencies of the corporeal elements and thus renders it self-sufficient and capable of pure knowledge.
[16] Both immaterial.
[17] Which incorporates all higher mental functions.
[18] In fact the second faculty serves as a first attempt to establish a link between mind and body, as we shall see later.
[19] Descartes recognizes the possibility of man being misled by his “sensuous” nature (through instinct) in the way animals are sometimes misled.
[20] As we shall see later, contemporary research in A.I. also shows that there is a connection between understanding and knowledge. In fact sensory data can only be interpreted (understood) by means of knowledge.
[21] In fact they are viewed as complicated, soft-tissue machines (with machine viewed in a rather deterministic and predictable way).
[22] Descartes argues that such unconscious functions are especially demonstrated while we are asleep. Actually the concept of body’s volition, the way it is introduced here (as body’s innate will power to maintain a mechanistic equilibrium), is quite reminiscent of contemporary “Cybernetics” principles.
[23] Such as the heart-beat and the reflexes
[24] Involving such medical terms and notions as “homeostasis” etc.
[25] A concept now explored by phenomenology, in abstraction from consideration of its intentional content.
[26] Body “stuff” and mind “stuff”. These two stuffs are fundamentally distinct and irreducibly different.
[27] This doctrine, called Parallelism, is also held by Spinoza.
[28] Gilbert Ryle was a 20th century philosopher and a professor of Metaphysical Philosophy in Oxford University.
[29] This is what Ryle calls “The Official doctrine”.
[30] The notion of “the ghost in the machine” . as he says.
[31] At the time psychology as a science had not yet acquired its physical (namely neurological) implications.
[32] What Descartes does with his causality model, we could compare with him trying to count using a scale.
[33] Introspection as a part of phenomenology is now used to approach the mind.
[34] This position brought about the introspective experimental psychology and in later years phenomenology.
[35] Leibniz’s theory of parallelism.
[36] The original work by Charles Robert Darwin was titled “The origin of species by means of natural selection” and was published in 1859.
[37] Darwin’s theory caused some philosophers who adopted it, to take a rather hylozoistic view of the world and argue that mind (however elementary) must be present in all matter.
[38] Artificial Intelligence.
[39] English mathematician (1912 - 1954).
[40] “Computing Machinery and Intelligence”, Mind Magazine, 1950.
[41] The program ELIZA, written by Joseph Weizenbaum in the mid-1960s, was used in an elaborate Turing Test with considerable success but only involving a rather narrow list of permitted subjects of conversation.
[42] The “Chinese Room” argument is based on exactly this concept.
[43] The word “natural” here gains a whole new importance as opposed to “artificial” in A.I.
[44] That which is understood by it (the idea it expresses).
[45] The set of things to which it is applied (its utility).
[46] And inside this model emulations (with the purpose of prediction) can take place.
[47] What is usually referred to as “Learning”.