Descartes is considered the first modern philosopher because he made subjective thought important and because he elevated the body side of man to a position almost equal to the mind. In this regard, he is considered the father of both physiological psychology and rational psychology, and his theory of interactionistic dualism formed the basis of most conceptions of the relationship between mind and matter.

1. What are the two major resolutions to the mind body problem?

2. What are the two major solutions to the problem of dualism?

3. Why was Descartes considered the father of modern physiology?

4. What was his theory of neurology?

Science now shifts to the north, away from Italy and Germany where it had established its roots, to France, England, and Holland where gentlemen scholars in the seventeenth century became leisurely scientists. They possessed time, casually explored ideas, reflected unhurriedly, and amused many. In the end, their activities added to mankind's comforts and reduced the number of deadly plagues. Descartes was a leader in this new occupation of gentleman scholar. He is said to represent the beginnings of modern philosophy. He was a brilliant and pompous man who traveled broadly, partly to escape the responsibilities of publishing and partly to learn from the larger book of the world.

Descartes was not a robust man. His health was precarious. In infancy he contracted tuberculosis, a fact which prompted his parents to name him Rene, for Renatus, which means "reborn," perhaps because his parents thought he had come back to life (Durant, v. 7, p. 637). He discovered ways to conserve his energies, such as staying in bed during the early morning hours. His tutors, recognizing this need for rest, usually overlooked his frequent absence from early morning classes. During these hours of relaxation, Descartes spent considerable time just thinking. It was this "thinking time" which led him both to the discovery of the analytic geometry and to the subjective side of the mind of man.


Descartes began his inquiries by a study of all the known available treatises. The more he studied, the more skeptical he became about the existence of ultimate answers to the world's most perplexing questions. Since writers differed, the truth seemed nowhere very secure. So Descartes devised a test for truth. He doubted everything and hoped to find an idea he could not doubt -- truth. He successfully doubted every idea, except one -- the very fact that he was doubting.

Descartes could not refute the fact of his questioning. So that became the one reality. He arrived, therefore, at one conclusion -- someone was doing the thinking, namely he. The dictum of Descartes' discovery was: "I think, therefore, I am." He had arrived at an objective observation, that he existed, but he had arrived at it subjectively, by the route of his own experiences. Neither the sense world out there nor the supernatural world above had produced this truth. It had emerged from within. This individual relativism and increasing self-consciousness marks the beginning of modern philosophy. Thereafter, man begins to rely upon his own consciousness and rational mind as a method for seeking truth.


Descartes' discovery convinced him that there were two realities -- a material world and a spiritual world, a world of matter and a world of mind. Here was an old problem revisited. The dualistic tradition had begun with Judaic Christian religion. It was continued by Galileo's conception of two kinds of qualities in the world -- primary and secondary qualities. And still later, Newton, at the time of Descartes, furthered dualistic thinking by suggesting that the experience of color originated from powers in objects to excite a medium in the nerves (Kantor, 1970). The eighteenth century English philosopher, Thomas Hartley, developed an elaborate system to explain the origin of simple and complex ideas. The physical vibrations of Newton were made the basis for similar and corresponding vibrations within the nervous system. This conception of two kinds of phenomena gets reflected in modern times by the Gestaltists's isomorphism or the behaviorist's transformation of stimuli into sensations.

Dualism solved some problems, but it created others. There were different resolutions to this problem (Vartanian, 1953). Some simply ignored the difference between body and mind. Another solution,called monism, united the two together under one reality. Spinoza attempted to unite mind and matter as a part of God's being. Locke emphasized the importance of matter. Berkeley made all things mind. Hume threw both out. The materialists, like the French empiricists, or those holding an identity theory like Wilhelm Reich today, recognize that mental activities exist, but that they have a physical basis.

But those who maintained that there were two different realities had the problem of explaining how two different worlds appear as one. How do physical phenomena change into mental phenomena? How do they become integrated? There were two major resolutions to this puzzle -- interactionism and psychophysical parallelism. The first was proposed by Descartes who believed that mind and body interact, that one causes the other. The second point of view, proposed by Leibnitz, was a variance of occasionalism of Malenbranche who suggested that the two realities only had the appearance of cause and effect, but that there was one cause (God) behind both of them. In psychophysical paralellism, mind and body are correlated together but do not have a causative relationship. We will examine Leibnitz's theory later.


Descartes' solution to the mind-body problem was called "interactionism," a point of view which held that there are two realities, matter and mind. Because they interacted with each other, there was some illusion of a unified world. The belief that mind could influence matter and matter could influence mind remained the dominant view for four centuries and is the predominant one today. Psychosomatic medicine is a prime example of this kind of thinking. Such a position was central to Freud's belief that the mental or psychic life could create physical symptoms, as in hysterical reactions; or that the physical world could create psychic experiences or feelings, like when libidinal energy is blocked and comes out in psychic work -- day dreaming, night dreaming, fantasies, projections, etc.

Descartes did not give undue emphasis to either the material or the mental side of man. There was considerable tradition for both points of view as represented by monistic theorists. The materialists had been represented by Democritus and Epicurus during Greek antiquity, and later by Hobbes in the seventeenth century. The mentalists were supported by Plato and Aquinas. Following Descartes, persons representing different systems would use him to support or extend their point of view. During the long tradition of Aristotle, which lasted through the middle ages, the mind of man was placed above matter.

Matter was the rock bottom of Aristotle's entelechy (Vartanian, 1953). But what Descartes did, according to Vartanian (p. 10) was to take the "Res Extensa," the material and extended side, and raise it up to the level of "Res cogitans," the mind. The material or the natural side of man then became as equal to and important as the mental side. This point of view coincided with the emergence of technology during the seventeenth century. Natural philosophy flourished and, according to Vartanian, helped to usher in and insure a firm footing for what became known as the period of "naturalism" in the eighteenth century.

Descartes' physical theory was really a "corpuscular" theory. Science was a study of the components of matter -- their size, shape, and motion. Cartesian (or Descartes') philosophy was really a revitalization of Epicureanism, in both its materialistic and atomistic points of view, though Thomas (1879) says Descartes was really not an atomist (did not conceive of matter as being indivisible of space). Gone was that "active force" of Aristotle. In its place were substituted the notions of "general laws of motion, the principles of mechanics, the modifications of matter, and the figure, situation, and arrangement of corpuscles (Vartanian, 1953, p. 66)." Change and development in nature could be expressed as mechanical phenomena rather than the result of some rational cause. This was good Epicurean doctrine. It was, however, antithetical to those characteristics of emergence, development, and change, which Leibnitz attributed to matter at that same time.


Descartes was known as the father of physiological psychology and the father of reflexology, both of which played major roles in contemporary psychology. He had noted that when a mock blow is aimed at a person's eyes, the eyelids would close; or when a child reached toward a fire, he would automatically withdraw his hand. Descartes reasoned that the animal spirits were "reflected" back to the brain (McHenry, 1969, p. 71). These movements were inborn, automatic, and did not involve voluntary control from the brain. This was the only kind of movement of which animals were capable. Men, therefore, were just like the animals in this regard. But men had one unique characteristic which animals did not possess -- a soul. Animals had only bodies, but humans had two realities -- one body (material) and one mind (spiritual). This dualistic conception of man continued down through the present day and frustrated every attempt to reconcile the difference between animals and men.

The mechanical explanation which Descartes developed was based on his observations of reflexive movements and his observation of the popular mechanical figures in the royal gardens at Versailles. He used these as a basis for proposing an automaton model of humans; at least he attempted to explain as much as possible by reference to such a mechanistic model. In so doing, Descartes was criticized for drawing an analogy from physics in the absence of acceptable biological principles and for violating the principle that "knowledge of structure must precede a study of function (Esper, 1964, p. 222)." Descartes did not hesitate to suggest functional principles rather than simply describing the architecture of the body. For this reason he is considered the father of modern physiology.

Descartes' neurology is more primitive than his psychology. He paraphrased Galen's pathway theory that the nervous system consisted of hollow tubes conducting animal spirits. Since the animal spirits, as Galen had proposed, are located in the head, how could they then influence the body? Looking for a plausible organ to integrate spiritual and physical activity, Descartes noticed that one organ, the pineal gland, was located at the base of the brain and had no mirrored duplicate.

Since the soul, mind or spirit, was unitary and undivided, then the place where it influences the body must be a single, unitary, undivided place. The pineal gland fits these criteria. He assumed the gland was responsive to voluntary instructions or will, and would turn so that animal spirits might flow into whichever tube the mind directed.

These subtle fluids were "like a wind or very fine flame (Esper, 1964, p. 221);" they coursed through the nerves, enlarged the muscles, and thereby created movement. The body in turn could send spirits to the pineal gland and thereby affect the mind. This pathway theory of the nervous system was similar to, and presumably based upon, Harvey's pathway theory of the circulatory system, published a few years earlier.

One of the major issues of the seventeenth century was how does one explain movement. Natural philosophers had long wondered about the movement of the stars and of the earth. Copernicus, Bruno, Galileo, Newton -- each had attempted a solution to the motion of heavenly bodies. Explanations which contradicted church dogma were quickly rejected. Descartes never faced very serious criticism from church fathers. As a good Catholic, he attempted to accommodate Christian principles. God, as"first mover" in the universe, initiated activity. After that, the amount of motion remained constant. Since God initiated the laws, the universe ran mechanically according to rules. The laws of nature and the rules of mechanics were the same. This readiness to believe that nature followed prescribed rules and laws was not so startling when one considers, as Mason suggests, that the statute laws of the times supported absolute monarchs in political positions. The religious philosophy was essentially a product of Jewish legislators. It was also consistent with the Calvinistic doctrine of an absolute ruler (Mason, 1953, pp. 135-137).


Consistent with his interest in absolute laws, Descartes began his thinking with certain apriori first postulates. From these he made deductions which could then be verified. Descartes' kind of science was mathematico-deductive and therefore different from Bacon's descriptive, classificatory, primarily inductive approach. Intuition may suggest the first premises. For example, one might begin reasoning from certain apriori ideas, such as the innate notions of motion, extension, or God. This belief in the independent existence of intuitive forms was a return to a Platonic point of view. It "called men back to the old paths of Pythagoras and Plato . . . the reaction against the long reign of Aristotle has begun (Singer, 1959, p. 227)."

Neither generalizations nor books held great interest for Descartes. Scholarly products containing conflicting points of view he considered to be mostly opinion. How could one believe any single position, if one could not believe them all? And if you believed all, you were committed to a morass of contradiction. Descartes recognized that many persons prospered by peddling ideas based on little more than fantasy. Disenchanted by the deceptions of alchemists, astrologers, and magicians, he gave up the world of letters and scholarship, traveled widely as a youth, and sought only those truths residing within himself and in "the great book of the world." During these travels, Descartes corresponded with only one person, a Parisian monk named Mersenne. The correspondence between these two men was sufficiently good to be published. Descartes, however, did not feel a need to create a more formal statement, although Mersenne believed that Descartes had an obligation to share his thinking with the world.

Descartes recognized the value of constructive social contributions. He believed, in fact, that the utilitarian was a major test of value, having little use for generalizations which possessed little or no redeeming social value. He said, "It is, properly speaking, to be worth nothing, if one is not useful to somebody (Vartanian, 1953, p. 19." The ultimate criterion of acceptable knowledge was the degree of benefit to man; and the ultimate benefit to man was through medicine -- healing the body to maintain life or the mind to maintain sanity. Consequently, both the body and the mind were integrated in the science of medicine.

Based on this practical criterion, his theory of knowledge included three areas: 1) medicine, 2) technology, and 3) morality. These fields were all interrelated, and their contribution to the good life was the basis for evaluating the merits of scientific advances.

This interest in a better world for man added considerably to the materialistic flavor of Cartesian philosophy. The immediately practical is the more clearly visible and the more clearly visible is the more materialistic. The increased interest in medicine, physiology, and other biological sciences contributed considerably to materialistic philosophies emerging in France, Germany, and eventually in America.

Descartes was known as the first modern philosopher. He earned this title because he directed questions about life and the universe to man himself. He reversed philosophy's inspection of the stars to a focus on the innermost regions of the mind. But he also described man as part animal, possessing mechanisms of animal movement. Descartes thus becomes the first modern philosopher because he expanded on the question of man's duality, the mind-body problem which became a central issue for the next four hundred years. One philosopher after another was subsequently to argue for whether mind or matter or both were central to an understanding of the human condition. His Discourse on Methods became one of the classics of western literature.



Now test yourself without looking at the reading.

1. Descartes is generally considered to be the first:

a. major psychologist
b. naturalistic theorist
c. German philosopher
d. modern philosopher

2. Descartes' concept of reality was:

a. monistic
b. dualistic
c. parallelistic
d. spiritualistic

3. The dualism of Descartes was called:

a. interactionistic
b. parallelistic
c. double aspect
d. monistic

4. Descartes emphasized which of the following?

a. matter
b. mind
c. both were equally emphasized

5. Descartes is known as the father of ___________________psychology.

a. physiological
b. social
c. reflexology
d. developmental

6. Monism is a philosophical position meaning belief in:

a. only one reality
b. belief-in mind and body
c. interactionism between mind and body
d. parallelism between mind and body

7. "Cartesian" is an adjective referring to:

a. mind-body problem
b. monistic thinkers
c. anything representing Descartes
d. 17th century philosophy

8. The nervous system worked such that animal spirits:

a. were different and produced different sensations
b. flowed from the mind to the muscles
c. were created by the pineal gland
d. were coordinated by the pineal gland.

7 or more correct, go to Module 3.

Less than 7 -- Complete exercises on next page.



1. The dictum which is so often associated with Descartes and which best explains his conclusion of reality is _______________________________________________.

2. Those two realities about which Descartes said explained humans, were:
a. ________________________.
b. ________________________.

3. The kind of dualism which assumes that while body and mind are independent of each other they give the illusion of coordination, is called: __________________________________________.

4. Descartes elevated the ______________________________ side of man to a new level of importance.

5. According to Descartes, the interaction of body and mind interacts in a place called the ______________________________.

6. There are two major solutions to the mind body problem: monism, the belief that there is just one reality, either mind or matter; and dualism, the belief that there are two separate realities. The contemporary psychologist Wilhelm Reich proposes in his orgone theory that there is a physical basis to all mental phenomena. This point of view makes him a ________________________.

7. Descartes was considered the father of modern physiology because he:
a. suggested that the human body functioned according to principles independent of any mind or spirit.
b. believed that movement could occur without a brain.
c. held that involuntary action was coordinated by the pineal gland.
d. advocated a mechanical theory of the function of the body.


4. Material, Matter, Body 7. A,B,D

3. Psychophysical parallelism 5. Pineal gland

1. "I think therefore I am." 2. Matter (body), mind 6. Monist




1. According to Descartes:
a. Matter and the body are extended substance
b. The soul has no physical location
c. Animals are automata
d. All of the above

2. Among those ideas that Descartes considered to be assured of acceptance because of the certainty and inevitability with which they appear to the mind are:
a. Space
b. Time and motion
c. Geometrical axioms
d. All of the above

3. Which of the following concepts is contained in the philosophy of Descartes?
a. Consciousness (apperception) is made up of many relatively unconscious perceptions (petites perceptions) .
b. Innate ideas exist without experience and these ideas come to the mind with such certainty that their acceptance is assured
c. Man is born with a mind void of any ideas. It is only through experience that all man's knowledge is gained.
d. None of the above

4. Which of the following is not one of the concepts of Descartes?
a. Dualism of mind and body and their interaction
b. The point of interaction between the soul and body occurs at the pineal gland
c. The concept of innate ideas, which are not derivable from experience
d. Leads a tradition of activity psychology

5. Descartes made the physical side of man:
a. More important than the mental
b. Less important than the mental side
c. As important as the mental side
d. Not important al all

6. A monist might be which of the following?
a. materialist
b. mentalist
c. parallelist
d. interactionist


Go to Unit 3 Table of Contents

July 27, 2000