The conscious mind is not at the center of the action in the brain; instead, it is far out on a distant edge, hearing but whispers of the activity.
THE UPSIDE OF DETHRONEMENT
The emerging understanding of the brain profoundly changes our view of ourselves, shifting us from an intuitive sense that we are at the center of the operations to a more sophisticated, illuminating, and wondrous view of the situation. And indeed, we’ve seen this sort of progress before.
On a starry night in early January 1610, a Tuscan astronomer named Galileo Galilei stayed up late, his eye pressed against the end of a tube he had designed. The tube was a telescope, and it made objects appear twenty times larger. On this night, Galileo observed Jupiter and saw what he thought were three fixed stars near it, strung out on a line across the planet. This formation caught his attention, and he returned to it the following evening. Against his expectations, he saw that all three bodies had moved with Jupiter. That didn’t compute: stars don’t drift with planets. So Galileo returned his focus to this formation night after night. By January 15 he had cracked the case: these were not fixed stars but, rather, planetary bodies that revolved around Jupiter. Jupiter had moons.
With this observation, the celestial spheres shattered. According to the Ptolemaic theory, there was only a single center—the Earth—around which everything revolved. An alternative idea had been proposed by Copernicus, in which the Earth went around the sun while the moon went around the Earth—but this idea seemed absurd to traditional cosmologists because it required two centers of motion. But here, in this quiet January moment, Jupiter’s moons gave testimony to multiple centers: large rocks tumbling in orbit around the giant planet could not also be part of the surface of celestial spheres. The Ptolemaic model in which Earth sat at the center of concentric orbits was smashed. The book in which Galileo described his discovery, Sidereus Nuncius, rolled off the press in Venice in March 1610 and made Galileo famous.
Six months passed before other stargazers could build instruments with sufficient quality to observe Jupiter’s moons. Soon there was a major rush on the telescope-making market, and before long astronomers were spreading around the planet to make a detailed map of our place in the universe. The ensuing four centuries provided an accelerating slide from the center, depositing us firmly as a speck in the visible universe, which contains 500 million galaxy groups, 10 billion large galaxies, 100 billion dwarf galaxies, and 2,000 billion billion suns. (And the visible universe, some 15 billion light-years across, may be a speck in a far larger totality that we cannot yet see.) It is no surprise that these astonishing numbers implied a radically different story about our existence than had been previously suggested.
For many, the fall of the Earth from the center of the universe caused profound unease. No longer could the Earth be considered the paragon of creation: it was now a planet like other planets. This challenge to authority required a change in man’s philosophical conception of the universe. Some two hundred years later, Johann Wolfgang von Goethe commemorated the immensity of Galileo’s discovery:
Of all discoveries and opinions, none may have exerted a greater effect on the human spirit.… The world had scarcely become known as round and complete in itself when it was asked to waive the tremendous privilege of being the center of the universe. Never, perhaps, was a greater demand made on mankind—for by this admission so many things vanished in mist and smoke! What became of our Eden, our world of innocence, piety and poetry; the testimony of the senses; the conviction of a poetic-religious faith? No wonder his contemporaries did not wish to let all this go and offered every possible resistance to a doctrine which in its converts authorized and demanded a freedom of view and greatness of thought so far unknown, indeed not even dreamed of.
Galileo’s critics decried his new theory as a dethronement of man. And following the shattering of the celestial spheres came the shattering of Galileo. In 1633 he was hauled before the Catholic Church’s Inquisition, broken of spirit in a dungeon, and forced to scrawl his aggrieved signature on an Earth-centered recantation of his work.2
Galileo might have considered himself lucky. Years earlier, another Italian, Giordano Bruno, had also suggested that Earth was not the center, and in February 1600 he was dragged into the public square for his heresies against the Church. His captors, afraid that he might incite the crowd with his famed eloquence, attached an iron mask to his face to prevent him from speaking. He was burned alive at the stake, his eyes peering from behind the mask at a crowd of onlookers who emerged from their homes to gather in the square, wanting to be at the center of things.
Why was Bruno wordlessly exterminated? How did a man with Galileo’s genius find himself in shackles on a dungeon floor? Evidently, not everyone appreciates a radical shift of worldview.
If only they could know where it all led! What humankind lost in certainty and egocentrism has been replaced by awe and wonder at our place in the cosmos. Even if life on other planets is terribly unlikely—say the odds are less than one in a billion—we can still expect several billion planets to be sprouting like Chia Pets with life. And if there’s only a one-in-a-million chance of life-bearing planets producing meaningful levels of intelligence (say, more than space bacteria), that would still predict several million globes with creatures intermingling in unimaginably strange civilizations. In this way, the fall from the center opened our minds to something much larger.
If you find space science fascinating, strap in for what’s happening in brain science: we’ve been knocked from our perceived position at the center of ourselves, and a much more splendid universe is coming into focus. In this book we’ll sail into that inner cosmos to investigate the alien life-forms.
FIRST GLIMPSES INTO THE VASTNESS OF INNER SPACE
Saint Thomas Aquinas (1225–1274) liked to believe that human actions came about from deliberation about what is good. But he couldn’t help noticing all the things we do that have little connection with reasoned consideration—such as hiccuping, unconsciously tapping a foot to a rhythm, laughing suddenly at a joke, and so on. This was a bit of a sticking point for his theoretical framework, so he relegated all such actions to a category separate from proper human acts “since they do not proceed from the deliberation of the reason.”3 In defining this extra category, he planted the first seed of the idea of an unconscious.
No one watered this seed for four hundred years, until the polymath Gottfried Wilhelm Leibniz (1646–1716) proposed that the mind is a melding of accessible and inaccessible parts. As a young man, Leibniz composed three hundred Latin hexameters in one morning. He then went on to invent calculus, the binary number system, several new schools of philosophy, political theories, geological hypotheses, the basis of information technology, an equation for kinetic energy, and the first seeds of the idea for software and hardware separation.4 With all of these ideas pouring out of him, he began to suspect—like Maxwell and Blake and Goethe—that there were perhaps deeper, inaccessible caverns inside him.
Leibniz suggested that there are some perceptions of which we are not aware, and he called these “petite perceptions.” Animals have unconscious perceptions, he conjectured—so why can’t human beings? Although the logic was speculative, he nonetheless sniffed out that something critical would be left out of the picture if we didn’t assume something like an unconscious. “Insensible perceptions are as important to [the science of the human mind] as insensible corpuscles are to natural science,” he concluded.5 Leibniz went on to suggest there were strivings and tendencies (“appetitions”) of which we are also unconscious but that can nonetheless drive our actions. This was the first significant exposition of unconscious urges, and he conjectured that his idea would be critical to explaining why humans behave as they do.
He enthusiastically jotted this all down in his New Essays on Human Understanding, but the book was not published until 1765, almost half a century after his death. The essays clashed with the Enlightenment notion of knowing oneself, and so
they languished unappreciated until almost a century later. The seed sat dormant again.
In the meantime, other events were laying the groundwork for the rise of psychology as an experimental, material science. A Scottish anatomist and theologian named Charles Bell (1774–1842) discovered that nerves—the fine radiations from the spinal cord throughout the body—were not all the same, but instead could be divided into two different kinds: motor and sensory. The former carried information out from the command center of the brain, and the latter brought information back. This was the first major discovery of a pattern to the brain’s otherwise mysterious structure, and in the hands of subsequent pioneers this led to a picture of the brain as an organ built with detailed organization instead of shadowy uniformity.
Identifying this sort of logic in an otherwise baffling three-pound block of tissue was highly encouraging, and in 1824 a German philosopher and psychologist named Johann Friedrich Herbart proposed that ideas themselves might be understood in a structured mathematical framework: an idea could be opposed by an opposite idea, thus weakening the original idea and causing it to sink below a threshold of awareness.6 In contrast, ideas that shared a similarity could support each other’s rise into awareness. As a new idea climbed, it pulled other similar ones with it. Herbart coined the term “apperceptive mass” to indicate that an idea becomes conscious not in isolation, but only in assimilation with a complex of other ideas already in consciousness. In this way, Herbart introduced a key concept: there exists a boundary between conscious and unconscious thoughts; we become aware of some ideas and not of others.
Against this backdrop, a German physician named Ernst Heinrich Weber (1795–1878) grew interested in bringing the rigor of physics to the study of the mind. His new field of “psychophysics” aimed to quantify what people can detect, how fast they can react, and what precisely they perceive.7 For the first time, perceptions began to be measured with scientific rigor, and surprises began to leak out. For example, it seemed obvious that your senses give you an accurate representation of the outside world—but by 1833 a German physiologist named Johannes Peter Müller (1801–1858) had noticed something puzzling. If he shone light in the eye, put pressure on the eye, or electrically stimulated the nerves of the eye, all of these led to similar sensations of vision—that is, a sensation of light rather than of pressure or electricity. This suggested to him that we are not directly aware of the outside world, but instead only of the signals in the nervous system.8 In other words, when the nervous system tells you that something is “out there”—such as a light—that is what you will believe, irrespective of how the signals get there.
The stage had now been set for people to consider the physical brain as having a relationship with perception. In 1886, years after both Weber and Müller had died, an American named James McKeen Cattell published a paper entitled “The time taken up by cerebral operations.”9 The punch line of his paper was deceptively simple: how quickly you can react to a question depends on the type of thinking you have to do. If you simply have to respond that you’ve seen a flash or a bang, you can do so quite rapidly (190 milliseconds for flashes and 160 milliseconds for bangs). But if you have to make a choice (“tell me whether you saw a red flash or a green flash”), it takes some tens of milliseconds longer. And if you have to name what you just saw (“I saw a blue flash”), it takes longer still.
Cattell’s simple measurements drew the attention of almost no one on the planet, and yet they were the rumblings of a paradigm shift. With the dawning of the industrial age, intellectuals were thinking about machines. Just as people apply the computer metaphor now, the machine metaphor permeated popular thought then. By this point, the later part of the nineteenth century, advances in biology had comfortably attributed many aspects of behavior to the machinelike operations of the nervous system. Biologists knew that it took time for signals to be processed in the eyes, travel along the axons connecting them to the thalamus, then ride the nerve highways to the cortex, and finally become part of the pattern of processing throughout the brain.
Thinking, however, continued to be widely considered as something different. It did not seem to arise from material processes, but instead fell under the special category of the mental (or, often, the spiritual). Cattell’s approach confronted the thinking problem head-on. By leaving the stimuli the same but changing the task (now make such-and-such type of decision), he could measure how much longer it took for the decision to get made. That is, he could measure thinking time, and he proposed this as a straightforward way to establish a correspondence between the brain and the mind. He wrote that this sort of simple experiment brings “the strongest testimony we have to the complete parallelism of physical and mental phenomena; there is scarcely any doubt but that our determinations measure at once the rate of change in the brain and of change in consciousness.”10
Within the nineteenth-century zeitgeist, the finding that thinking takes time stressed the pillars of the thinking-is-immaterial paradigm. It indicated that thinking, like other aspects of behavior, was not tremendous magic—but instead had a mechanical basis.
Could thinking be equated with the processing done by the nervous system? Could the mind be like a machine? Few people paid meaningful attention to this nascent idea; instead, most continued to intuit that their mental operations appeared immediately at their behest. But for one person, this simple idea changed everything.
ME, MYSELF, AND THE ICEBERG
At the same time that Charles Darwin was publishing his revolutionary book The Origin of Species, a three-year-old boy from Moravia was moving with his family to Vienna. This boy, Sigmund Freud, would grow up with a brand-new Darwinian worldview in which man was no different from any other life-form, and the scientific spotlight could be cast on the complex fabric of human behavior.
The young Freud went to medical school, drawn there more by scientific research than clinical application. He specialized in neurology and soon opened a private practice in the treatment of psychological disorders. By carefully examining his patients, Freud came to suspect that the varieties of human behavior were explicable only in terms of unseen mental processes, the machinery running things behind the scenes. Freud noticed that often with these patients there was nothing obvious in their conscious minds driving their behavior, and so, given the new, machinelike view of the brain, he concluded that there must be underlying causes that were hidden from access. In this new view, the mind was not simply equal to the conscious part we familiarly live with; rather it was like an iceberg, the majority of its mass hidden from sight.
This simple idea transformed psychiatry. Previously, aberrant mental processes were inexplicable unless one attributed them to weak will, demon possession, and so on. Freud insisted on seeking the cause in the physical brain. Because Freud lived many decades before modern brain technologies, his best approach was to gather data from the “outside” of the system: by talking to patients and trying to infer their brain states from their mental states. From this vantage, he paid close attention to the information contained in slips of the tongue, mistakes of the pen, behavioral patterns, and the content of dreams. All of these he hypothesized to be the product of hidden neural mechanisms, machinery to which the subject had no direct access. By examining the behaviors poking above the surface, Freud felt confident that he could get a sense of what was lurking below.11 The more he considered the sparkle from the iceberg’s tip, the more he appreciated its depth—and how the hidden mass might explain something about people’s thoughts, dreams, and urges.
Applying this concept, Freud’s mentor and friend Josef Breuer developed what appeared to be a successful strategy for helping hysterical patients: ask them to talk, without inhibition, about the earliest occurrences of their symptoms.12 Freud expanded the technique to other neuroses, and suggested that a patient’s buried traumatic experiences could be the hidden basis of their phobias, hysterical paralysis, paranoias, and so on. These problems, he guessed, were hidden from the co
nscious mind. The solution was to draw them up to the level of consciousness so they could be directly confronted and wrung of their neurosis-causing power. This approach served as the basis for psychoanalysis for the next century.
While the popularity and details of psychoanalysis have changed quite a bit, Freud’s basic idea provided the first exploration of the way in which hidden states of the brain participate in driving thought and behavior. Freud and Breuer jointly published their work in 1895, but Breuer grew increasingly disenchanted with Freud’s emphasis on the sexual origins of unconscious thoughts, and eventually the two parted ways. Freud went on to publish his major exploration of the unconscious, The Interpretation of Dreams, in which he analyzed his own emotional crisis and the series of dreams triggered by his father’s death. His self-analysis allowed him to reveal unexpected feelings about his father—for example, that his admiration was mixed with hate and shame. This sense of the vast presence below the surface led him to chew on the question of free will. He reasoned that if choices and decisions derive from hidden mental processes, then free choice is either an illusion or, at minimum, more tightly constrained than previously considered.