HISTORY’S RIGID, ROCKY, AND GOOFY WAY OF THINKING ABOUT CONSCIOUSNESS
“Speak English!” said the Eaglet. “I don’t know the meaning of half those long words, and, what’s more, I don’t believe you do either!”
—Lewis Carroll, Alice’s Adventures in Wonderland
SIGMUND FREUD DIED the year I was born—1939. That year there were a lot of zany ideas being kicked around about the nature of our psychological lives, many of them dreamed up by Freud himself. He is not popularly remembered as such, but Freud was a biologist at heart, a reductionist. He was committed to the belief that the brain generated the mind in a deterministic way, a view shared by many of today’s neuroscientists. Now we recognize that many of his ideas were pure fantasy, but up until the 1950s they were so broadly accepted that they were the dominant testimony for psychological issues in a U.S. court of law!
It has been in my lifetime, not Freud’s, that humankind has learned the most about how the brain does its tricks. Wild speculation about the forces governing our mental lives has given way to specific knowledge about the molecular, cellular, and environmental influences that underlie our existence. Indeed, the past seventy-five years of research have provided a wealth of information about the brain, sometimes even yielding organizing principles. I am sure Freud would have reveled in our new world and would have gladly put his incredible imagination to work on the new science of the brain. Yet the deep puzzles that faced scientists of all stripes in the previous century, and indeed going back to the ancient Greeks, are still present today. How on earth does lifeless matter become the building blocks for living things? How do neurons turn into minds? What should be the vocabulary used to describe the interactions between the brain and its mind? When humankind finds some answers, will we be disheartened by what they are? Will our future understanding of “consciousness” simply not be fulfilling? Will it be simple yet cold and harsh?
Wading into the history of the study of consciousness is daunting. For one thing, it is littered with the complex and abstract writings of philosophers. Even John Searle, one of today’s leading philosophers of consciousness, has admitted: “I probably should read more philosophy than I do. But I think a lot of works of philosophy are like root-canal work, you just think you’ve got to get through that damn thing.”1 Add to that the view of the great philosopher David Hume, who provided strong arguments that most of the questions asked by philosophers simply couldn’t be answered using the methodologies of logic, mathematics, and pure reason. Nonetheless, philosophers got us thinking about the mind, the soul, and consciousness. From ancient times on, they have had a huge influence.
“Consciousness” is a relatively modern idea. The very word, as now broadly used in dozens of contexts (Marvin Minsky would call it a “suitcase word” because it is packed full of various meanings), was invented in its modern sense only in the mid-seventeenth century by René Descartes. It does have origins in the Greek word oida—“to have seen or perceived and hence to know”—and the Latin equivalent scio, “to know.” But the ancients did not have an explicit concept of consciousness. There was interest in how the mind worked, where thoughts came from, and even whether a purely physical process was involved, but most early thought wound up concluding that mental life was the product of an immaterial spirit. And when consciousness is framed as immaterial spirit, it’s hard to start thinking about underlying mechanisms!
Over the centuries, the concept of the mind and the concept of the soul have been involved in an on-again, off-again relationship. For most of written history, the very idea that personal psychological reality was a thing, a something to be studied, was largely nonexistent. Our brains, our thought structures, and our emotions presumably haven’t changed, so what were we humans thinking about? But, as will become evident, the concept of consciousness has radically changed over the past twenty-five hundred years. Its ethereal beginnings and its current meaning have little to do with each other.
We humans need a new way to think about the problem, and with luck, this book may offer some new beginnings. First, however, as is always the case, it’s best to look back before plunging forward.
Early Stirrings: Successes and Blunders
The ancient Egyptians and Mesopotamians were the Western world’s philosophical forebears. In their concept of the world, nature was not an opponent in life’s struggles. Rather, man and nature were in the same boat, companions in the same story. Man thought of the natural world in the same terms as he thought of himself and other men. The natural world had thoughts, desires, and emotions, just like humans. Thus, the realms of man and nature were indistinguishable and did not have to be understood in cognitively different ways. Natural phenomena were imagined in the same terms as human experience: generous or not so much, dependable or spiteful, and so on. These ancients of the Near East did recognize the relation of cause and effect, but when speculating about it they came from a “who” rather than a “what” perspective. When the Nile rose, it was because the river wanted to, not because it had rained. There was no science to suggest otherwise.
Not so with the ancient Greeks. The earliest Greek philosophers were not priests charged by their communities to consider spiritual matters, as they were in the Near East. They were not professional seers. They were a bunch of amateurs puttering around in their garages unconstrained by dogma, curious about the natural world, and happy to share their thoughts. When they started to ask about their origins, they did not ask “who” the progenitor was, they asked “what” the first cause was. This was a monumental change of viewpoint for humankind that the archaeologist and Egyptologist Henri Frankfort called “breathtaking”:
[T]hese men proceeded, with preposterous boldness, on an entirely unproved assumption. They held that the universe is an intelligible whole. In other words, they presumed that a single order underlies the chaos of our perceptions and, furthermore, that we are able to comprehend that order.2
Frankfort goes on to explain how the Greek philosophers were able to make this leap: “The fundamental difference between the attitudes of modern and ancient man as regards the surrounding world is this: for modern, scientific man the phenomenal world is primarily an ‘It’; for ancient—and also for primitive—man it is a ‘Thou.’”
A “Thou” is a someone with beliefs, thoughts, and desires, doing their thing, not necessarily stable or predictable. On the other hand, “It” is an object, not a friend. “It” can be related to other objects in whatever seems the most reasonable organization. One can build and expand on these relationships and seek universal laws that govern behavior and events under predictable, prescribed conditions. Seeking the identity of an object is an active process. On the contrary, understanding a “Thou” is a passive process in which one first receives an emotionally charged impression. A “Thou” is unique and unpredictable and known only insofar as it reveals itself. Each “Thou” experience is individual. You can coax a story or a myth from an interaction with a “Thou,” but you cannot draw a hypothesis. The transition away from “Thou” and toward “It” made scientific thinking possible.
The Greeks’ huge advance in perspective created an atmosphere that catapulted Aristotle into a scientific life. Aristotle’s stance was that the job of science was to account objectively for the “why” of things, which led to his doctrine of causality. For him, scientific knowledge about something (say, some X) included all the ways the “why” question could be answered: if X was caused by Y, or if Y was at least a necessary condition in order for X to happen, then this is the type of assertion that belongs to science. He postulated four causal categories: material, formal, efficient, and final. So if one were to ask “Aristotle, why a cart?,” he would tell you the material cause was wood, the formal cause was its blueprint, the efficient cause was its construction, and its final cause was … he just wanted one.
For Aristotle, the natural world was a web of what biological theorist Robert Rosen calls causal entailments: X comes with all its Ys. Rosen points out that Aristotle’s whole idea was to show that no one mode of explanation sufficed to understand anything, because the causal categories do not entail each other. For example, knowing how to build something does not entail understanding how it works; knowing how something works does not entail knowing how to build it. Also, for Aristotle, science was content-determined. It was independent of the method by which it was studied.
The scientific method as practiced today is a formal system in which a hypothesis produces its inferences, that is, its effects: the hypothesis entails its effects. Another way to say this is that the cause comes before the effect. This presents a problem when asking Aristotle’s final-causation “why” question. Let’s go back to “Why the cart, Aristotle?” Why did Aristotle have a cart parked in front of his home when hours earlier it had been parked at Acropolis Depot? He had seen the cart (which entailed the effects of the material, formal, and efficient causes) and wanted it. Here, the tables were turned and the effect came before the cause. This is a no-no in the Newtonian world, where a state can only entail subsequent states. Thus, Aristotle’s final causation, as a separate category, was lost to science. We will see later what harm this has done to biology.
Among other things, Aristotle wanted to know more about the human body and how it worked. This was a bit challenging, since the Greeks had a taboo against human dissection. Aristotle skirted this issue by performing numerous animal dissections. From what he learned, he devised a system of classifying organisms, the scala naturae, a graded hierarchical scale based on the type of “soul” each possessed. At the base were plants, which he posited have a vegetative soul responsible for growth and reproduction. Needless to say, man sits at the top of the scala naturae.
Aristotle didn’t stop there. He proposed that animals possess a sensitive soul powering self-movement, perception, sensation, appetite, and emotion. Unique to humans and nested within the sensitive soul is a rational soul that provides us with the special powers of reason, rational will, thought, and reflection and sets us apart from those lower on the scala. Most important, and reflecting the revolution in human thinking, the “knowledge” of these powers arrived at not by sheer introspection or mental meanderings, but by observing how one connects with the surrounding world. The “it,” that is, an object such as the world around us, could be studied and examined. We forget that this very idea, now commonly accepted, didn’t exist a few thousand years ago! Clearly, ideas do have consequences, and, happily, we continue to be captivated by the idea and power of scientific observation.
Aristotle got the process of science right, but his conclusions about where thoughts come from were all off. If a modern student had made a mistake like the one he made, the student would have failed the course. Aristotle knew from the actions of animals and humans that they can perceive the world. From his dissections, Aristotle noted that some animals had no visible brains at all. He concluded, therefore, that the brain appears to be of not much account. The first thing he saw appearing in the embryos he studied was the heart, so he put the soul there, which in the case of humans included the rational soul. Aristotle did not mean “soul” in a spiritual sense, as he did not think it continued on after death. He meant the organ that gives rise to sensation, to our knowledge of the world. He thought that the rational soul, which was the source of human intellect, required some perceptual mechanisms; therefore, it required a body with its parts and organs. Yet he did not think that there was a body part or an organ that thinks. Aristotle never even mumbled the word “conscious,” but he did ask, “How do we know our own perceptions?” Overall, Aristotle got the ball rolling and got people thinking about humankind’s physical nature.
The monumental stirrings that started in Greece were quickly exported. In 322 B.C., not long after Aristotle died, Herophilus and Erasistratus, two Greek physicians living in Alexandria, defied the taboo on dissecting human bodies and went at it. They became the first to discover the nervous system and write about it. They also found the ventricles, the empty chambers inside the brain. Herophilus decided that these chambers must be where the intellect was located, and that from them, spirits flowed down through hollow nerves out to the muscles, making them move. While they didn’t get it exactly right, they are commonly credited with being the first neuroscientists. Unbelievable as it now may seem, the Greek culture that engineered and built the Parthenon didn’t know about brains. And the Egyptian culture that engineered and built the pyramids didn’t know how the brain worked at all.
History rattled along for another four hundred years, a microsecond in evolutionary time. Rome became the dominant force in the Mediterranean and somehow was able to attract the wondrous physician Claudius Galenus (Galen) from Pergamum, a Greek city on the Aegean coast of modern-day Turkey. Galen finished his medical training an empiricist, having immersed himself in the teachings of Herophilus and Erasistratus in Alexandria, now under Roman rule. In ancient Greece, the Empiric school of medical practice relied on the observation of phenomena and on experience, not on dogmatic dicta. Galen returned to Pergamum for his first job: gladiator doctor. Because the Romans, like the Greeks, did not allow human dissection, Galen never did any. Instead, he honed his knowledge of anatomy and surgery with the gory remains of his patients and with daily animal dissections, primarily on Barbary macaques. He took his firsthand knowledge; a healthy helping of the teachings of his distant mentors, Herophilus and Erasistratus; and a pinch of Hippocrates’ theory that the body was composed of four humors, and combined them into a new conception of the body and its machinations. He earned himself a stellar reputation. Soon he was on his way to Rome, and his growing fame led him to become the personal physician to the emperor, Marcus Aurelius.
Galen’s contributions to medicine are stunning. He was the first to recognize that there is a difference between arterial and venous blood. We now know that arterial blood is rich with oxygen, while venous blood carries much less (your tissues have stolen it so they can breathe), a difference that is exploited in the functional magnetic resonance imaging (fMRI) studies of the brain that are the cornerstone of modern neuroscience. Galen gave the first depiction of the four-chambered human heart; he updated the knowledge of the circulatory system, the respiratory system, and the nervous system. He made some anatomical blunders, of course—one being a meshwork of blood vessels, the rete mirabile, which he located at the base of the human skull, based on dissections of oxen. This was a major mistake and a cautionary tale about inductive reasoning. As was shown years later, humans flat-out don’t have a rete mirabile!
Nonetheless, Galen understood that food and breath are necessary for human life, and maintained that the body transforms them into the flesh and spirit. Amalgamating the works of Hippocrates, Plato, Socrates, and Aristotle, Galen came up with the idea of a material tripartite soul. Using Plato’s designations of the rational, spiritual, and appetitive souls, he assigned each one an anatomical location: the rational soul was in the brain, the spiritual soul was in the heart, and the appetitive soul was in the liver. Each performed a separate function. The appetitive soul controlled the natural urges of the body, such as hunger and thirst, survival instincts, and bodily pleasures. It was animated by natural spirits. The spiritual soul contained the emotions and passions and was animated by a vital spirit that somehow formed in the heart from blood and air delivered via the lungs. The rational soul controlled cognition such as perceptions, memory, decision making, thought, and voluntary action. Galen saw no distinction between the mental and the physical. One can begin to see the groundwork being laid for such modern ideas as conscious versus subconscious, the id and the ego, the rational and the intuitive. The specifics are different, but the underlying ideas were emerging even in A.D. 200.
Galen took a stab at mechanism. He envisioned a vital spirit, a life-giving force that enters the body and is purified in the rete mirabile. The purified spirit then flows into the ventricles of the brain, where it becomes an animal spirit and enables the rational soul’s cognition. While Galen got the organ for cognitive functions right, he did not really understand it. He located all the processing in the empty ventricles. That is like saying the best part of the doughnut is the hole.
Still, one of Galen’s major contributions to the future of medicine was the notion that different organs perform different functions. Beginning to differentiate the body’s organs into various machines performing separate functions was a tremendous idea. Today, one of the goals of modern neuroscience is to discover what functions the various parts of the brain perform. With each century, neuroscience continues to get more and more specific about which particular brain systems contribute to our overall mental life. In true reductionist style, Galen did not distinguish between the physical and the mental, yet at the same time he held on to the idea of an immortal soul. Time and time again, as we will see, the brilliant forebears of modern neuroscience abandoned their fierce reasoning skills and, deus ex machina, threw in a spook at the end of their analysis.
Throughout his life, Galen was a firm believer in personal observation and experimentation over established teachings, but he didn’t completely practice what he preached. His epistemology was rooted in his philosophical training, which included the teaching of Plato, Aristotle, and the Stoics, and he mixed and matched some of it with his observations to create an overarching theory of medicine. Yet he most likely would have been completely dismayed by the influence he had on medicine for the next thirteen hundred years. Galen’s findings were taken as gospel for over a millennium! Some of his ideas were instituted as doctrines by the new Christian church. In the Old Testament, the soul died with the body, just as Aristotle had asserted. The new Christians, however, had a different view of the soul. They conceived of it as immortal, living beyond the life of the body, just as Plato and Socrates had suggested. Although Galen believed there to be no distinction between the mental and the physical, the Christians liked Galen’s idea that the soul was located in the airy ventricles, tucked away from the lusty, sinning body. So that became the Church’s doctrine of the bodily location of the newly immortal and immaterial soul. Sensation was ensconced in the front ventricle, understanding was in the middle ventricle, and memory brought up the rear.
From the early Greeks through Galen’s period of influence, a period of seventeen centuries of human thought, thinking about the nature of human existence found us wallowing in high-powered confusion. Most of the talk was about souls, not minds—and certainly not consciousness. Plato and Socrates argued for a tripartite immortal soul, partly rational, partly spiritual, and partly appetitive. Aristotle also reasoned we had souls, but he said they were not immortal. The early students of the brain, and of anatomy in general, went back to saying that they were immortal but that there was no difference between the mental and the physical. Ideas die hard, even in the light of an emerging science. As we shall see, these primitive ideas are still in play today.
Setting the Stage for Descartes and the Idea of Mind/Body Dualism
It wasn’t until the sixteenth century that Galen’s anatomy was challenged by a young anatomist, Andreas Vesalius, based at the University of Padua. Vesalius started scratching his head when he compared his own human dissections with Galen’s drawings. Luckily for him (and modern science), he suffered no human-dissection taboos, and the local judge had no qualms about sending him the cadavers of condemned criminals. Vesalius came to the realization that not only had Galen never dissected a human, but much of his anatomy was just plain wrong. Vesalius did not have the greatest tools when it came to dissecting the brain. He sawed it in slices from the top down, mauling the lower sections as he went, somewhat like slicing a ball of mozzarella di buffala with a dull knife. But one thing became perfectly clear: there was no rete mirabile. One aspect of science that we have learned over the course of centuries that is hugely important is to check and double-check an earlier claim.
A few years earlier another anatomist, Niccolò Massa at the University of Bologna, had discovered that the ventricles were filled not with airy spirits but with fluid. Now Vesalius found that they were not the perfect spheres with fleshy vaults that Galen had described. Enough things were wrong with Galen’s descriptions that Vesalius had to rewrite (or redraw) the book, so to speak. With the help of apprentices from Titian’s workshop in Venice, De Humani Corporis Fabrica Libri Septem (On the Fabric of the Human Body in Seven Books) was published in 1543, showing skeletons (with or without their muscles or circulatory systems) strolling with walking canes in the Italian countryside, casually leaning against tree trunks or columns, or even glancing down at books resting on lecterns. It was a big hit, especially with students.
After having relieved so many cadavers of their skin, Vesalius wanted to keep his own. The structure that was purported to purify the vital spirits and change them to animal spirits was simply not there. More disturbingly, the ventricles alleged to house the soul were not full of air, nor did they resemble the Church’s descriptions of them. Vesalius did not question his faith or his immortal soul, but he knew that the Church fathers would if he challenged their doctrine—risky business in the era of the Inquisition. Vesalius thought that perhaps the brain and not the ventricles was where the business of the soul (sensation, understanding, and memory) was taking place. Either way, he used his head and kept quiet.
Scientists were turning the heat up a notch at the end of the sixteenth century by providing more observations. Back in Padua, Galileo was not just questioning Aristotle’s (and the Bible’s) notion of an Earth-centered universe but also using mathematics, measurements, and experiments to prove Aristotle wrong. The upshot was that Galileo declared that the laws of nature—that is, the laws that govern the physical world—were mathematical, which is to say mechanistic. Accused of trying to reinterpret the Bible, he was tried by the Roman Inquisition, told to shut up about the Sun, and put under house arrest.
In Paris, however, ideas were emerging. Marin Mersenne, a fellow mathematician as well as a theologian, philosopher, music theorist, and monk, supported Galileo. He lived in the convent of L’Annonciade and hosted frequent discussions in his cell with notable thinkers and scientists from across Europe. He also maintained an extensive and far-reaching correspondence with others. Mersenne had decided that if the Church was to survive the onslaught of new science and the complaints of heretics, it had to accept and absorb the view that the universe was mechanistic. God could just as easily rule over a universe that followed natural laws he had created as over a human-centered one. In fact, come to think of it, why wouldn’t he in his omniscience have created a universe that could work automatically without maintenance?
Attending the sessions was another French philosopher-mathematician-scientist-priest, Pierre Gassendi. Gassendi subscribed to the notion that the world is composed of atoms, a theory first proposed in Western culture in the fifth century B.C. by Leucippus and Democritus. Atoms were described as indestructible, immutable, and surrounded by a void. Different kinds of atoms had their own specific size and shape, and all were in constant motion. Atoms could join together, and Gassendi called the resulting structure a molecule, which has a different shape and different intrinsic properties. All the macroscopic substances in the world are made up of various atoms. Gassendi did not find this belief heretical in the least. God created atoms as he did everything else.
Nonetheless, Gassendi missed the mark when he posited two types of souls. One was made up of atoms, hooked up with the nervous system and the brain, and able to perceive, feel pleasure and pain, and make decisions. There was one thing, however, that Gassendi was certain about: no atoms in any combination could reflect on themselves or perceive anything beyond what was supplied by sensation. Thus, he concluded humans must have another soul, a rational soul that was immaterial. This soul, however, was not on its own. He believed it was fused to the body during life and was dependent on the body for information from the outside world. Nonetheless, upon death, the soul proved to be immortal and fled away.
Enter the young René Descartes, philosopher, mathematician, and rationalist, who also frequented Mersenne’s sessions and was all for the idea that the physical world was made up of particles and ran like a machine. A flamboyant dresser favoring taffeta, feathers, and swords, he liked to strut his stuff around Paris, which, at the time, had its own visionary version of EuroDisney’s “It’s a Small World” ride in the French Royal Gardens. It was made up of water-powered automatons that moved, made sounds, and played musical instruments. The automatons were cleverly activated by the pressure exerted on the garden’s tile footpaths when people walked on them. Automatons, known better today as robots, were actually rather commonplace at the time. No doubt most visitors to the garden were charmed by them.
Descartes, however, was a philosopher, one for whom a walk in the park was never just a walk in the park (hence the taffeta and feathers). He knew that these human-like robots were machines run by inanimate external forces. Yet they appeared to make rational voluntary movements. He got to thinking that certain aspects of our bodies were much the same. Our reflexes are just this: an external stimulus from the environment causes something to happen in the nervous system that results in a pre-programmed motor response. No director of action need be in charge. No soul is necessary. He also considered that a reflex response need not just be a motor response; it could instead be an emotional or cognitive one, such as a memory. Once one started down this particular garden path of thought, the theoretical possibilities of behavior generated by some sort of reflex reaction to an external stimulus were limitless. But they also were deterministic: stimulus x will always produce reaction y. Descartes gave this idea his approval for machines and animals, but did it apply to humans, too? No free will? No voluntary choices? No personal accountability for our actions? No morals or sins? Machines ourselves? That was too much.
Backing away from the void of such existential despair, Descartes began developing his history-changing idea. But the damage was already done to the study of biology. The distinguished theoretical biologist Robert Rosen points out that while no one can say what a living organism is, it is easy to say what it is like. Rosen says that Descartes got it backward: “[H]e proceeded to turn the relation between these automata, and the organisms they were simulating, upside down. What he had observed was simply that automata, under appropriate conditions, can sometimes appear lifelike. What he concluded was, rather, that life itself was automaton-like.* Thus was born the machine metaphor, perhaps the major conceptual force in biology, even today.”3 And born, too, the completely deterministic world that it implies.
Sure, your body will involuntarily jerk your lower leg up when you are tapped on the knee, but you can voluntarily jerk it up, too. These are two very different events, one in which your body reacts to an external stimulus and the other, according to Descartes, instituted by your mind. While the first can be described mechanically using the laws of physics in a chain of events that may lead all the way back to creation, the second, in his view, was a two-link causal chain: you will it, and presto—it happens. Why did you will it? Because you wanted to: nothing physical there to study. Just a desire. What Aristotle would dub the final cause.
Descartes rejected the idea that voluntary events were a reflex or physical mechanism that could be described scientifically. He finally came to the conclusion that while the body was governed by physical laws, human action is caused or driven by an autonomous agent in charge, the rational soul, not made up of matter—that is, nonphysical, non-mechanistic, and not constrained by any natural laws; something from nothing. This soul was capable of consciousness, free will, abstract thinking, doubting, and morality. This is known as mind/body dualism: the idea that the body consists of physical machinery and the mind consists of nonphysical (immaterial) cognitive machinery.
Descartes was a card-carrying mathematician and scientist, and he wanted to rationally figure out the true nature of being. Since his rational mathematical approaches were working well for the physical world (he had developed analytical geometry and discovered the law of refraction, among other things), he tried to approach man’s true nature using the same rational method. First, he had to chip away at everything he could possibly doubt in order to find a certainty, a foundation on which to build his arguments. It turned out that he could figure out a way to doubt just about everything, even that his mother was his mother, that the sun would rise the next day, or that he had slept in his bed in Paris the previous night rather than cavorting around Rome. He could even doubt that he had a body. After all, one’s belief that one has a body is based on sensory perceptions, which are sometimes wrong. If they are wrong once, well, they could be wrong all the time. There was one thing he knew for sure, however, that he couldn’t doubt. He knew for sure that he existed. In the very process of doubting, he was affirming that he was a thinking thing. Hence, Cogito ergo sum—I think, therefore I am.
Now that Descartes thought he had a solid foundation on which to build, he wanted to derive once and for all the true nature of being, and do it step-by-step, scientifically. He went on thinking that, because he could doubt that he had a body, he could doubt that he existed physically. From this little trail of thought he concluded, “I knew that I was a substance the whole essence or nature of which is to think, and that for its existence there is no need of any place, nor does it depend on any material thing; so that this ‘me,’ that is to say, the soul by which I am what I am, is entirely distinct from body, and is even more easy to know than is the latter; and even if body were not, the soul would not cease to be what it is.”4 His thinking continued in a tortuous manner, drawing conclusions from arguments that, from our current perspective, are easy to poke holes in. For example, one can easily see that just because one can doubt that one exists as a physical thing, it does not necessarily follow that one is correct and one is not a physical thing, nor that the body is not essential for thoughts. This was the shaky basis of Descartes’s first argument for mind/body dualism.
Yet Descartes’s arguments were without the advantages of modern knowledge. His conclusions and ideas shaped intellectual thought until modern times, and his mind/body dualism, his separation of the mind from the body and brain, has had a stranglehold on philosophers for the past 350 years. Yet at the time, his contemporaries had trouble with his conclusions. Many of his supporters, including Princess Elisabeth of Bohemia (whose correspondence with Descartes was extensive), wondered how this immaterial mind interacts with the material body. Descartes admitted to Elisabeth that he didn’t have a good answer.5 He might have been comforted to know that the question is still being batted around today. He did try, though. Descartes searched the brain and found what he thought to be the location of mind/brain interaction: the pineal gland. He wrote to her, “My view is that this gland is the principal seat of the soul, and the place in which all our thoughts are formed. The reason I believe this is that I cannot find any part of the brain, except this, which is not double.”6 You have to wonder if he wasn’t grasping at straws here. After all, his search consisted of looking at calves’ brains, which he already said had no immaterial soul, and at Galen’s incorrect drawings.
While working all this out, Descartes slipped in the word “conscious” just once, in the Third Meditation, paragraph 32, thereby introducing the word to philosophy. As did all educated men at the time, he wrote in Latin, so he actually used the Latin word, conscius. Translations into French and English have not been so specific with their interpretations or the use of the word, but they employ it when Descartes himself used the verbs “to think” or “to know.” Objections to its use were immediately raised. He may have been sorry he ever used it, because he continued to waffle on what he meant, vacillating as to whether consciousness is reflective—that is, a thought about a thought—or is simply thinking in general. At any rate, Descartes used the term to signify the knowledge we have of what is passing in our minds, which he argued was both indubitable and infallible, a conclusion he came to by logical reasoning. For example, if I am thinking that I have the best vineyard in the world, then I have no doubt that this is what I am thinking: it is indubitable. Also, I am not wrong that this is what I am thinking: it is infallible. Because he knew for sure what he was thinking, that meant he knew his mind better than he knew his body. For Descartes, his consciousness could not deceive him.
Descartes and the French gave birth to a philosophical industry that has striven ever since to make sense of an idea of consciousness that was never clearly defined from the start. In the end, it was not unlike the famous remark Supreme Court justice Potter Stewart made about pornography: “I shall not … attempt further to define [it] … and perhaps I could never succeed in intelligibly doing so. But I know it when I see it.”
* * *
We leave seventeenth-century France equipped with a mechanistic universe and two differing descriptions of the mind. Prior to Descartes, the notion of a soul, whether material or immaterial, dominated human thought. It was as if the conscious presence we humans feel and experience makes it almost impossible to think our “soul” is a piece of flesh. Understandably, it is hard, and even downright annoying, to think that after one toils for a lifetime, the party is over at death. Aristotle tried to put us on the right course on these matters, making it clear that with death the soul died. However, even after two thousand years of human knowledge accumulation, most humans do not subscribe to the simple reality that it is our bodies (and brains) that generate what we are, in all our biological and cultural complexity.
On the road to the present, Descartes boldly separated the immortal soul (and, with it, the mind) from the mechanistic universe and mechanistic body. With the mind and flesh considered separate, the mind became the central puzzle; it was deemed immaterial, indubitable, infallible, and immutable. By promoting the mind to supernatural status, Descartes took it off the table as an object of scientific study. Descartes could never explain how this immaterial mind interacted with the material body, but his theory profoundly gummed up the thinking about the physical reality of the mind for more than two hundred years. Many of his brilliant contemporaries, such as Pierre Gassendi, agreed that there was an immaterial rational soul because they were certain that no atoms in any combination could reflect on themselves or perceive anything beyond what was supplied by sensation. As strange and useless as these seventeenth-century ideas were at the time, the idea that mental states do exist is alive and well in twenty-first-century science. Instead of an immaterial mind floating around with each of us, modern science has moved the mind into the brain and made it very physical. The question that remains is: How on earth does that work?