After the extraordinary creativity that reigned at the early beginnings of the Academy, the scientific and philosophical disciplines of Europe fossilized themselves around the work of Plato and Aristotle. The existence of the soul, like so many other notions, became dogma. The fable was transformed into belief. The Renaissance is called renaissance precisely because some European intellectuals want the spirit of Plato’s Academy to be reborn: the desire to seek and develop, with all of the material that is available, a better knowledge of self and what surrounds us.
I am going to follow a common practice in epistemology. Having discussed Plato’s Idealism, I will leap right over 2,000 years of discussions to land alongside René Descartes (1596–1650). This practice was already recommended by Descartes, as he thought that those that came after Plato and Aristotle “laid more store on following their opinions than on seeking something better” (Descartes, 1644, p. 177). Descartes’s message is not that he is the greatest intellectual since Plato, but that, the science developing in Europe since the sixteenth century finally permits one to go further than what had been written in Europe about human nature up until then.
The true mirror of our thoughts is the conduct of our lives. (Montaigne, 1592, Essais, I, XXVI, p. 247)
Descartes was born in France in 1596, in The Hague, a city of Touraine. He attended the Jesuit College of La Fleche, on the banks of the Loire, where he studied law, mathematics, and philosophy. He remained in contact with certain Jesuit priests all of his life.1 This did not prevent him from taking Galileo’s side at the occasion of his trial in 1633. Nonetheless, he had too much fear of the Church to publish his writings on astronomy, which adopt the theses of Galileo and Kepler.
Descartes became a soldier. Having traveled in Germany and France, he established himself in the Netherlands, where it was possible to think with relative freedom. He felt close to Montaigne’s humanism. The latter was frightened by the bloody and cruel religious wars that tore Europe apart for a century. These wars were notably caused by individuals who were convinced they were right and unable to value those who thought otherwise. The Catholics and their inquisition massacred the Protestants, the Gnostics, and the free thinkers. After having had to defend themselves, the Protestants also become all too often intolerant. Montaigne proposed a humanism that questions all forms of idealism. He therefore rejects the possibility that a human being might know what is true and false. Only God is thus able. Idealism is thereby not rejected but relativized. The god of the humanists is the smallest common denominator to that of the Catholics, the Protestants, the Muslims, and the Jews.
In this spirit Descartes thought that the scientific method is a good way to help human beings seek the truth together, instead of looking for it by killing each other. The choice of Amsterdam was not insignificant for Descartes. Amsterdam has much in common with Athens. Holland was part of the very Catholic and very tyrannical Holy Roman Empire of Charles V and was annexed to Spain, which was close to the Catholic Inquisition under Philip II. In liberating itself from Spain, Holland became a relatively tolerant Calvinist republic.2 The Netherlands rapidly built a colonial empire for themselves in diverse continents and became one of the richest European nations.3 Just like Athens, she partially democratized her internal institutions without renouncing her sometimes cruel domination of her colonies. And like Athens, the Netherlands became a center for art and philosophy that was characterized as a golden age of human thought.
Descartes finished his days in Sweden, guest of the Swedish Queen Elizabeth, where he died of pneumonia in 1650.
The battleground of the Renaissance, among other things, manifested itself in the need to know how a human body was really constituted: a curiosity shared by artists, learned people, and physicians alike. The Church required that people accept that all that could be known about the body had been written by Aristotle, Galen, and the Bible. Those who only referred to Aristotle were called Peripaticians. All the same, most physicians knew to what extent this knowledge was limited and that it did not allow for the care of the suffering that confronted them. Artists, physicians, and philosophers had organized a large clandestine network to make anatomical observation of stolen cadavers and the mutual exchange of their observations possible. Galileo recounts an anecdote about the debate between a Humanist and Peripatetic physicians:
It happened on this day that he [an anatomist from Venice] was investigating the source and origin of the nerves, about which there exists a notorious controversy between the Galenist and Peripatetic doctors. The anatomist showed that the great trunk of nerves, leaving the brain and passing through the nape, extended on down the spine and then branched out through the whole body, and that only a single strand as fine as a thread arrived at the heart. Turning to a gentleman whom he knew to be a peripatetic philosopher, and on whose account he had been exhibiting and demonstrating everything with unusual care, he asked this man whether he was at last satisfied and convinced that the nerves originated in the brain and not in the heart. The philosopher, after considering for a while, answered: “You have made me see this matter so plainly and palpably that if Aristotle’s text were not contrary to it, stating clearly that the nerves originate in the heart, I should be forced to admit it to be true.” (Galileo, Dialogue Concerning the Two Chief World Systems, 1630, II, p. 108)
The Peripatetic teachers of the day defended the theory that diverse organs were the seat of various psychic propensities: the liver for passions, the brain for judgments, and the heart for affects.4 Peripatetic physicians assumed that there are connections between the mind and the organs that do not pass through the soul.
The idea that knowledge must be compatible with what is observable is referred to as empiricism. If that is all there had been to their endeavors, Galileo and his colleagues would have met the criterion of empiricists but not that of scientists. This generation of thinkers searches for rigorous observations and most of all for laws; that is, a theoretical construct that describes the mechanisms that organize what is observed. This combination makes Galilean physics a science. He postulates that the entire universe organizes itself coherently by following a logic that is close to what mathematics and geometry describe. This logic can be used to analyze all observed phenomena and all phenomena that will be observed. This idea could have been a theory only as interesting as all of the others, if it had not revealed itself particularly fruitful, easy to teach, and easy to disseminate. Furthermore this theory could be improved upon by constant research.
These principles gave me a natural way of explaining the union of the soul with the organic body, or rather their conformity with one another. Soul and body each follow their own laws; and are in agreement in virtue of the fact that, since they all represent the same universe. There is a pre-established harmony among all substances. (Leibniz, 1714, Monadology, 78, p. 10)
According to the philosopher Edmund Husserl,5 Galileo’s generation also postulated that each event of the universe can be defined in function of fundamental properties that are applicable everywhere: location, space and time, weight, size, and so on. The calculations become possible when the object studied is reduced to an “idealized” form (sphere, cube, etc.) associated to the properties of the real object (location, weight, size, etc.). Once these properties have been isolated, the physicist can compute how an object can be situated in a causal chain. This type of procedure permits scholars to construct an explanatory scientific system. This vision is monistic and materialistic: the universe is composed of one basic material substance. The relationship between the properties and mathematics makes it possible to sort out the great laws of a causal system that allows one to understand the functioning of the universe. Science would henceforth associate empiricism (e.g., experimental physics) and mathematical theory (e.g., theoretical physics). If one accepts that every particle of the universe obeys these laws, then one also assumes that the thoughts of the mind follow these same principles. Even today, no one knows what the properties of the mind really are. But if we follow this vision, the day when psychologists will be able to isolate the properties of a thought or a sentiment will be the day when it becomes possible to foresee, mathematically, the way these phenomena relate to each other.
Galileo’s absolute formulation leaves little place for God. Some philosophers of the subsequent generation, like Descartes, distinguished a dimension of the universe that effectively follows the scientific laws (matter) and a parallel dimension whose dynamics are distinct, near to those that actuate God (soul):6
The parallelist argumentation is still used today. There cannot be more than one object at the same time in the same space; but there can be several thoughts at the same time in the same space (in an individual). I cannot extend both arms, as on a cross, and touch my chest at the same time; but I can have the desire to do both gestures at the same time. The parallelists of the seventeenth century think that matter acts on matter and reacts only to matter. In similar fashion, the mind can only act on the mind, not on matter. According to Husserl, such a clear distinction between the substance of the mind and that of matter is a creation of the seventeenth century. In the preceding centuries, the differences between body and soul were more fluid.
A physical event is necessarily caused by an event that precedes it, whereas two thoughts that follow one another are not necessarily related and can be part of two independent causal systems. The soul and the body cannot interact directly because their functioning is so different. They are therefore part of two distinct dimensions.
Descartes had, at one moment, put forth the idea that the soul is “the assembly of the organs,”7 that is, the organization of the organs that constitutes an organism. But he did not have the means to explore this hypothesis. It is nonetheless so tempting that the subsequent generation of philosophers like Spinoza found ways to tease something out of this analysis.
This argumentation is different from that of Aristotle, for whom affects and logical thoughts emerge in a soul that is a dimension of the individual system:
It therefore seems that all the affections of soul involve a body-passion, gentleness, fear, pity, courage, joy, loving, and hating; in all these there is a concurrent affection of the body. In support of this we may point to the fact that, while sometimes on the occasion of violent and striking occurrences there is no excitement or fear felt, on others faint and feeble stimulations produce these emotions, viz. when the body is already in a state of tension resembling its condition when we are angry. . . . From all this it is obvious that the affections of soul are enmattered formulable essences. (Aristotle, Of the Soul, 1.1)
Aristotle also quotes Democritus, for whom breath is the medium through which the soul animates the organism.8
Spinoza proposed a compromise between the positions of Descartes and Aristotle. He maintains the distinction of the parallelistic dimensions, but he introduces three restrictions to the independence between soul and body:
Thus, a thought cannot influence the body; a gesture cannot influence the unfolding of ideas. However, these two independent causal systems are part of an individual system (or organism) that has an architecture. This architecture can influence and is sensitive to what goes on in each dimension. Therefore, there exist regulators between each dimension.9 These regulators have different properties, of a third type, that Spinoza will not be able to specify.
In his first great works, The Rules for the Direction of the Mind (1628) and The Discourse on Method (1637), Descartes observes how scholars think when they want to develop a scientific theory. He derives from their intellectual methods a set of rules that can be used by all those who want to become rigorous observers of the dynamics that animate the universe. These rules form a method of thinking composed of the following elements:
Descartes is convinced that this method can be applied to all domains, even the study of the soul. He wants to explain it, make it public, put it at the disposition of all those who want to think correctly.
The Protestants had showed that by printing the Bible and learning how to read, each Christian could do without religious hierarchies. He no longer had the need of intermediaries between himself and God’s message. Descartes follows an analogous reasoning. He begins with the Idealist’s conclusion that the soul of each individual knows how to think and possesses an intuition about what is True or False, Good or Evil. Any individual who can read a book that describes the scientific method of thinking has the inner capacity to use it. Once he knows these rules, he can learn to develop his inner potential in a way that will allow him to study the phenomena that interest him.
No objective science, no psychology—which, after all, sought to become the universal science of the subjective—and no philosophy has ever made thematic and thereby actually discovered the realm of the subjective. . . . It is a realm of something subjective which is completely closed off within itself, existing in its own way, functioning in all experiencing, all thinking, all life, thus everywhere inseparably involved; yet it has never been held in view, never been grasped and understood. (Husserl, 1936, The Crisis, III.A.29, p. 112)10
I always did and still do accept the innate idea of God, which Descartes upheld, and thus accept other innate ideas that couldn’t come to us from the senses. Now the new system takes me even further. As you’ll see later on, I think that all the thoughts and actions of our soul come from its own depths and couldn’t be given to it by the senses! But in the meantime I’ll set that aside and conform to accepted ways of speaking which purport to distinguish mental content that does come through the senses from mental content that doesn’t. These ways of speaking are sound and justifiable: the outer senses can be said to be, in a certain sense, partial causes of our thoughts. So I’ll work within the common framework, speaking of “how the body acts on the soul”. . .; and I shall look into why, even within this framework, one should say that there are some ideas and principles that we find ourselves to have though we didn’t form them, and that didn’t reach us through the senses though the senses bring them to our awareness. Descartes’ famous “cogito ergo sum” (I think, therefore I am) anchors all of the knowledge that God puts at the disposal of humans in the soul of each individual. It is in the interior of each soul that Descartes situates the intuitions of truth, the capacity to reflect and to know what one is thinking. Conscious thoughts are like soap bubbles floating about in the soul. In other words, contrary to Plato, Descartes situates the mind in the soul. (Leibniz, 1705, New Essays, I, p. 15)
When he has a feeling inside, how is he to know whether he is the only person on earth to have felt it, or even something like it? (Daniel Stern, 1990, Diary of a Baby, p. 1061)
To designate human explicit inner impressions, Descartes speaks not of consciousness but of thoughts. Thoughts are interior phenomena about which “we have immediate knowledge.”11 A thought is a reflexive mental activity, that is to say, a mental activity that perceives what is happening. This is the first explicit definition of the psychic system, or of the psyche of the Greeks: “By the term to think, I understand all that happens within us in such a way that we perceive it immediately by ourselves; that is why not only to hear, to want, to imagine, but also to feel is the same thing here as to think” (Descartes, 1644, The Principles of Philosophy, I, p. 574; translated by Marcel Duclos). There is a fine point here. Descartes does not tell us what thoughts are, only that we can have immediate knowledge of them. He does say that we are necessarily aware of them.
Certain thoughts are perceptions of events situated in the organism, like bodily sensations and sensory data. Other thoughts perceive what is going on outside of the organism. Other forms of thought have the task of organizing what has been detected by the senses. These “meta-perceptions” enable reasoning and reflection. This vocabulary was quite customary at that time. For example, the English philosopher Thomas Hobbes gives an analogous definition: “The secret thoughts of a man run over all things, holy, profane, clean, obscene, grave, and light, without shame, or blame; which verbal discourse cannot do, farther than the Judgement shall approve of the Time, Place, and Persons” (Hobbes, 1651, I.8.34, p. 55). Hobbes also insists on the fact that only the individual has access to his thoughts. A thought cannot be censured by another unless it is communicated by behaviors such as speech, gestures, or messages (books, performances, etc.).
At the end of his life, in The Passions of the Soul,12 Descartes makes the distinction between some thoughts as “our will” that come from the soul and go toward the body and “the passions” that are intrusions of the body into the dynamics of the soul. Body sensations are part of thoughts because they are part of what is perceived.
Our mind is nothing else than the sum of our inner experiences, than our ideation, feeling and willing collected to a unity in consciousness. . . . Conscious experience is immediate experience. . . . Our mental experiences are as they are presented to us. The distinction between appearance and reality necessary for the apprehension of the world without . . . ceases to have any meaning when applied to the apprehension of the thinking subject by himself. (Wilhelm Wundt, 1892, Lectures on Human and Animal Psychology, 30.V, p. 451f)
The term consciousness is today generally used to designate the human capacity to have impressions that one can explicitly perceive. This choice of term is problematic, as we shall now see. Some readers, for example, may have asked themselves why I did not just write that for Descartes thoughts are any conscious psychological phenomena. This definition is indeed adequate if one follows the twentieth-century English used in psychology. Yet taking this custom for granted would prevent us from perceiving several important issues and distinctions concerning conscious dynamics. For example, Descartes is often quoted as being the one who introduced the notion of consciousness in philosophy.13 To check this intellectual tradition, I downloaded all of Descartes’s work and searched for the term conscious. I thus discovered that Descartes uses the word only twice, in a particular way I discuss later on. Another important and related example is Freud’s work. He never uses the term consciousness because this word has no direct equivalent in German. The familiar association between Freud and the term unconscious has been introduced by English and French translators. Descartes and Freud use the same terminology: there are psychological events we “know of” (in German, bewusst) and others we do “not know of” (unbewusst). Yet as we shall see, in French, the term conscience exists. The first interesting point pertaining to this linguistic observation is that the general psychological vocabulary used in Freud’s day was probably more influenced by Descartes’s theory than is usually assumed. I am not talking of a direct influence, but of one that has implicitly engraved itself in cultural know-how. In the next sections, I show what theoretical issues can be highlighted by reconsidering how the term consciousness has been used and by differentiating the word from the phenomena that are presently labeled as conscious.
Conscience. Noun. An inner feeling or voice viewed as acting as a guide to the Tightness or wrongness of one’s behavior: he had a guilty conscience about his desires. —origin. Middle English (also in the sense “inner thoughts or knowledge”). (The New Oxford Dictionary of English, 1999)
And this was capable from then on of freeing me from all repentance and remorse which habitually agitate the consciences of those weak and wavering minds which allow themselves to proceed with vacillation to practice as being good things which they judge afterwards to be bad. (Descartes, 1637, Discourse on Method, Discourse, 3, p. 47)
In the seventeenth century, the word conscious had another meaning, closer to its Latin etymology. The first meaning of the word conscious in Latin, such as it evolved in ancient Rome, is that of a shared knowledge (cum-scio, “knowledge with”). This term was originally used in court proceedings. A fact became conscious for the ancient Romans when the court could establish, with the testimony of witnesses, a version of the facts that could be accepted by all. Hobbes14 perfectly summarizes the meaning of this term at that time: “When two, or more men, know of one and the same fact, they are said to be conscious of it one to another; which is as much as know it together” (Hobbes, 1651, I.7.31, p. 50).
The Latin word conscientia means complicity, confidence, intimate knowledge, conviction.15 This brings us back to the transpersonal dimension of the mind; but this dimension is examined from another angle than the one I brought up in the sections dedicated to platonic Idealism. For Descartes and Hobbes, there is consciousness when many people think that others have a thought similar to theirs. Consciousness is like a kind of electric plug of the mind that allows it to branch out on a network of social communication. The distinction is important. In one case, we have individual thoughts that influence only the individual who has them. In the other case, we have thoughts that circulate from soul to soul and form the support of the social networks, like justice, ideologies, art, or science. To know that we are many who follow a law or accept that the Earth turns around the sun is consciousness. In that sense, according to Hobbes, animals would not have consciousness.
Recently, several psychologists have become interested in phenomena that are close to the notion that consciousness is a form of shared thinking. They study how a psychological impression often emerges out of a co-construction between several persons.16 Thus, to designate the appearance of the conscious thoughts that an infant constructs while interacting with his parents, Philippe Rochat speaks of co-consciousness.17 Given the first meaning of the word conscious, the notion of co-consciousness, such as Rochat uses it, is a pleonasm. However, the pleonasm is necessary today as soon as we speak of something that is explicitly known by many people.
In psychotherapy, it is essential to distinguish between what an individual is conscious of and the conscious construction that is built between the psychotherapist and the patient. In analyzing a dream, the psychotherapist constructs, with the patient, a series of images that are associated to the way the patient experiences what is going on within and outside of himself. Experiencing in his own body the impact of the patient’s respiration, the body psychotherapist facilitates a dialogue that builds a representation of what the patient does to himself and others when he breathes in a particular fashion. In this type of discussion, which is central in psychotherapy, it is essential to differentiate sharply the thoughts of the patient, the thoughts of the therapist, and the co-construction that is created thanks to the dialogue between the therapist and the patient. This co-construction emerges out of an attempt to coordinate the elements contained in the two individual organisms.18
The second common meaning of the French word conscience in the seventeenth century connotes having a good or bad conscience. It consists of a type of thought strongly influenced by the moral and religious value system of the culture in which a person lives. That is the meaning Descartes associates with the term consciousness the two times where he uses the word conscience.
Aware. Adjective. Having knowledge or perception of a situation or fact. (The New Oxford Dictionary of English, 1999)
Men think themselves free, because they are conscious of their volitions and their appetite. (Spinoza, Ethics, 1677a, I. Appendix, p. 26)
All the perceptions of the human mind resolve themselves into two distinct kinds, which I shall call impressions and ideas. The difference betwixt these consists in the degrees of force and liveliness, which they strike upon the mind, and make their way into our thought or consciousness. (David Hume, 1737, Treatise of Human Nature, I.1.1, p. 7)
The most sophisticated meaning of the word conscious, in a dictionary of the English language,19 designates the capacity to have reflective thoughts, that is, to be able to perceive the existence of a thought. In this case, the dictionaries recommend the use of the term awareness. This meaning of the word conscious, in the sense of an intimate psychological capacity, appears around 1676, with some of Descartes’s students like Malebranche and Spinoza. Hobbes had announced this tendency when he writes that the French word conscience is about to lose its usual meaning: “Afterwards, men made use of the same word metaphorically, for the knowledge of their own secret facts, and secret thoughts” (Hobbes, 1651, I.7.31, p. 50). The idea of an “intimate consciousness” becomes generalized in the eighteenth century in the writings of popular authors like Jean-Jacques Rousseau and David Hume, to designate immediate knowledge, more or less intuitive, of a thing inside or outside of oneself.20 Today, this meaning derived from the French word conscience dominates to the point that we have forgotten its original meaning. In the psychotherapeutic literature, there is yet another complication: Freud’s opposition between the conscious and the unconscious on the one hand, and the use of the term awareness in schools such as Gestalt therapy on the other hand.21 Awareness is then used to designate what Freud would call preconscious dynamics. One cannot be conscious, at a given moment, of more than a few items, but we are surrounded by events we could become aware of if we paid attention to them. I may not realize that my fingers are taping rapidly on one of my knees, but if a person asks why I am moving my fingers in this way, I will immediately become aware of it. Or I may meet someone and not notice the color of this person’s eyes, as I was focusing on others aspects of his appearance. If somebody asks me if I noticed this person’s beautiful green eyes, I can then look again and notice them. One can also learn to develop a finer perception by using awareness exercises.
After this semantic digression, I use, like everybody, the word conscious to designate the thoughts of Descartes and the bewusst of Freud; but I maintain a clear theoretical distinction between the inner consciousness of an individual and the communication between the consciousness of more than one individual. The relevance of this distinction is evident as soon as we take into account the fact that a thought constructed by two organisms is not of the same nature as a thought constructed in one.
An “instinct” appears to us as a concept on the frontier between the mental and the somatic as the psychical representative of the stimuli originating from within the organism and reaching the mind as a measure of the demand made upon the mind for work in consequence of its connection with the body. (Freud, 1915b, Instincts and Their Vicissitudes, 214, p. 122).
The Descartes, Spinoza, and Leibniz trio gave precision to the framework still in effect: neurologists know how to study the nervous system, and psychologists know how to study the mind. In their discussions, psychologists and neurologists can notice that there exists connections between their respective domains, because a cervical lesion modifies specific capacities of the mind (even the Greeks and the yogis of antiquity knew this); however, they remain unable to describe the nature and the functioning of these connections. Neurologists are not able to explain the dynamics of the mind by observing the brain, and psychologists are not able to explain the dynamics of the brain by observing the mind. The more that the scientists go into details, the less they see solutions. On the other hand, that which psychologists observe can permit the elaboration of suppositions (of hypotheses) that can encourage a neurologist to observe the far reaches of an organism that one hitherto had the tendency to ignore, and vice versa.
The data from psychophysiology is closer to the imaginations of the Hindus and the Chinese who presuppose a series of complex links between many dimensions of the mind and the body. The Europeans, boxed in by the soul/body polarity of the Idealists, can only envision one body and one mind per person. Everything happens a bit as if a laboratory were to use ever more powerful microscopes to seek out, between two points, what allows them to draw a line on a sheet of paper. The more detailed the enlargement, the more powerful the microscope that explores the space between the points in the line formed by the ink from the pen, showing the detail of the cells of the paper’s cellulose, consequently finding nothing that could resemble what links the points in the line.
Crouching down into the world of his thoughts, Descartes hoped to be able to observe the junction between the soul and the body. However, because his thoughts observed but his thoughts, he found nothing. By incessantly fixing his sights on the space between the two points, he ended up seeing double. His imagination took over, as it does with all those who tried to clearly think about the juncture between body and thoughts. Descartes invented a gadget for himself that allowed him to express the ideas that have formed within him relative to this connection without being able to do so coherently. This gadget, which he names the H gland,22 has somewhat of the same function as Plato’s fables. I do not know why all those who try to define the junction between the soul and the body end up imagining an instructive but delusional mechanism like in the following examples:
These are all members of the intellectual aristocracy! On the other hand, persons who have maintained a classical and academic approach to the issue23 abandon us as soon as we look at the space that separates the two points of a line: the structure of the brain and the structure of a thought. They have one foot in psychology, the other foot in neurology, and remain unable to find a bridge.
Descartes and Leibniz both thought that God made the body and the soul separately, but in such a way that they could cooperate. It is only because God exists that Descartes lets himself think that the senses bring relevant information to the soul about what is happening around the organism. The I who thinks about the resources that God deigned to place in the soul is terribly dependent on the body and the senses to obtain information about what surrounds him. The flesh is made up of organic systems that we can begin to detail in a reliable way in the seventeenth century; it functions without the I’s ability to feel (by introspection) what is at play. The soul is indeed a reflexive system, but it is also a kind of impasse. Some information produced by the body is swallowed up by the soul and then emerges transformed. The body, according to Descartes, is the space from whence information leaves and returns.
The body has the capacity to react automatically to its environment via mechanisms like the reflexes that are observable in all animals. These reactions, often effective, have no need of the soul and seek her out only occasionally. The soul tries to influence these sensorimotor reactions so that the body and the soul can together create forms of behaviors that cannot be produced by the reflexes of the body. Descartes situates the affects (passions) at the heart of this to and fro:
This analysis is not so far from certain approaches in body psychotherapy like the one described by Jane R. Wheatley-Crosbie (2006) in an article that describes a cure during which “psyche’s return from soma’s underworld.” From the point of view of philosophers like Descartes and Spinoza, the individual cannot truly become himself without learning how to understand his passions and the way they impose the logic of the body on the dynamics of the mind. Consequently, a therapy of the soul is necessarily a form of body psychotherapy that focuses on how body and mind interact with each other.
William Harvey had described the circulation of the blood24 when Descartes was thirty years old. This discovery struck Descartes’s imagination, and he then set about using Harvey’s theory to describe the link between the soul and the body. He therefore devised a vision of the impassioned body, animated by wild dynamics, that is everything save what we ordinarily refer to as Cartesian. Descartes proposes a precise and detailed vision that takes into account all that is known, but one that invents connections where there is no evidence to allow for a view of the whole.
Descartes’s concept of the body is of a sort of hydraulic robot that is animated by great physiological systems that interact with each other like dancers at a ball. It appears as a precise choreography, probably foreseen by God; in practice, the dancers sometimes let themselves be carried away by their enthusiasm and bang into each other.
The body is composed of distinct systems such as the skeleton, the muscles, the nervous system, the circulation of the blood and the heart, the lungs, as well as the deeper organs (liver, spleen, kidneys, etc.). These systems are already relatively well known. Things become more difficult when Descartes tries to understand how these systems interact. He knows that certain organs discharge products into the bloodstream, that oxygen is transported by the blood—in short, that the blood links all of the tissues of the body. The arterial blood nourishes the tissues. Venous blood, as a sewage system, takes their toxins and distributes these waste products in diverse organs, principally the kidneys and the lungs. The second system that strongly participates in the organization of the human organism is the nervous system because it coordinates what the senses bring to the body, what certain nerves detect in the body, and the orders given to the muscles. For Descartes, matter is by nature living and dynamic without the soul having any role in it. The flesh has its own sensual and juicy dynamics, whereas the soul has its capacity for wisdom. After all, like the soul, the flesh was created by God. Where Descartes’s imagination becomes both stimulating and whimsical is when he sets about to describe, in The Passions of the Soul, the interactions between the circulation of the blood and the nervous system to try to define the dynamics between the soul and the body. This work is always full of learning if we read it attentively, trying to bring to mind the details of Descartes’s imaginative device.
Descartes knows that blood must fight gravity on the way to the head. He imagines that the heavier particles of blood stay at the bottom, and only the lighter and smaller particles irrigate the brain. The most refined ones are retained by the nerve tissues to become a “spirit” that will flow in the nerves and form the nerve impulses. The word spirit is to be taken here in the chemical sense, like a state between liquid and gas that breathes agreeably in a glass of cognac or brandy. Once it is admitted that the nervous fluids are refined blood, it becomes possible to think that (a) the dynamics of the heart can influence the nervous system, and (b) all that influences the nervous system can indirectly influence the circulation of blood. Thus, a muscle is a kind of bag that is treated in two ways by the blood:
The sensory organs provoke the movement of fluids in the nerves that can directly animate the muscles. This is the way Descartes explains the activity of the reflexes, or the habits that make a body move without the intervention of thoughts. Instincts,25 like hunger and thirst, are also mechanisms that arise from the body and make the fluids move toward the muscles and the soul.
For Descartes, there are three links between the soul and the body:
The important point that the H gland introduces into future psychology is that the link between the psyche and the soma is full of unforeseeable events that are therefore difficult to master and understand. The connections between the body and the psyche that are made via the H gland are subject to a great variability quite close to random. The large number of variables that can influence this gland at a given moment make it such that a stimulus (an animal approaches) can provoke different reactions (fear, courage, indifference) in different persons or in a person at a different moment or even arouse the three passions at the same time.
Descartes also shows the enormous physiological mobilization that accompanies the slightest reflex, the slightest stimulation, and the fact that a stimulus can, in the same instance, introduce a quick behavioral reaction and slowly become a thought in the soul. In this system, there can easily be conflict between several drives, between drives and the desires of the soul, or between the will and the drives.26 The soul can also influence a drive to regulate another drive. A passion is in general a high stake for the body (what does the body good and what does the body ill) that transforms itself into a thought to recruit the help of the soul. At the same time, a passion recruits the resources of the organism so that the will of the soul might have the logistic support necessary to act.
No one believes that the H gland could be the connection between body and thoughts. The current theories lean more favorably toward the first point on Descartes’s list (the connection between the psyche and the organization of the organism). However, in showing all of the forces and stakes at play that could move this gland, Descartes finds a metaphor that makes it possible to show the extraordinary power of the interactions between the realm of thoughts, the sensorimotor circuits, and the affective dynamics. He also shows that these interactions mobilize, in a massive way, the collection of physiological mechanisms—in other words, “the assembling of the organs.” Today, the organization of the organs is on the verge of being detailed by research; it serves as a foundation for the idea that psychological dynamics inevitably interact with the powerful currents of the organism.
A last important point in the mind of Descartes that will be taken up by Spinoza and in particular by Hume is that the domain of the passions play a crucial role in sorting out physiological mobilization, behavior, and thought.
Descartes shows how these systems are both heterogeneous and connected (linked notably by the blood). They are heterogeneous to the extent that they are constituted of materials so different that they do not have the same properties. The substances that link these systems (blood and nerve impulse) have properties that are their own. Finally, even in the soul, we find thoughts that have a different logistic support. The sensory data, the passions, and the instincts have distinct physiological mechanics that have different impacts on the soul and manifest differently thereon. The intellectual intuitions come from the soul, and they have an impact on the body that is not that of the perceptions, the passions, and the instincts.