In 1962, neurosurgeons Joseph Bogen and Philip Vogel split Bill Jenkins's brain. They did so to help Jenkins recover from severe epilepsy and enjoy a quality of life that he had missed for years. The results were astonishing; Jenkins fully recovered and went on to ordinary life, while the best medicine at that time couldn't help people with epilepsy like Jenkins. The idea of the operation was simple; the human brain has 86 billion neurons that communicate through electrochemical language, and despite its complexity, this network of neurons is usually stable, maintaining an orderly flow of messages. But just as a single car accident can disrupt traffic flow in a city, a sudden overload of off-beat signals in the brain can disrupt the flow of electrochemical messages through the brain. The brain is divided into two hemispheres, left and right. Each hemisphere has 43 billion neurons. But, despite the rich interconnections within the hemisphere, the bridge between the two hemispheres is a tiny cable, the corpus callosum. This brain area offers an excellent place to cut, thereby suspending the spread of debilitating surges from one hemisphere to another. The critical interest for Donald Hoffman and other cognitive scientists and philosophers in split-brain surgery, or what is scientifically known as "corpus callosotomy," wasn't the clinical success but the post-surgery changes in consciousness. The neurobiologist Roger Sperry and his student, later professor Michael S. Gazzaniga, conducted several famous experiments on split-brain patients, whose explanations revealed several astonishments about human consciousness. For example, in one of Roger's experiments, a person stares at a small cross in the center of a screen. Then two words flash on the screen for a tenth of a second, such as "KEY" to the left of the cross and "RING" to the right. Now, if you ask an ordinary person what they saw, the answer will be "KEY RING." But if you ask split-brain patients, they will answer "ring," and when you ask what kind of ring? They do not have anything to say. You then blindfold the split-brain patient and the patient to search using their left hand in a box full of items, a pencil, a ring, a fork, a key, a spoon, and a key ring. The left hand always looks for the key and rejects a key ring. After they take their left hand, pulling the key outside the box, you ask, "what's in your left hand?" they answer we do not know. You then ask the blindfolded patient to search in the box for the item whose name flashed on the screen using their right hand. Their right hand will hold a ring. Now, you ask the patient, "what's in your right hand?" they correctly say, "ring." While the patient still holds an item in each hand, you remove the blindfold, let them see both hands, and ask, "You said you saw the word ring. So why does your left hand hold a key?" The split-brain person either has no idea or narrates a false story to be reasonable. What happened in the experiment? Sperry's explanation of such experiments acquired him the Nobel Prize for Physiology and Medicine in 1981. In short, when you focus on the cross in KEY + RING, the neural pathways from the eye to the brain send KEY only to the right hemisphere and RING only to the left. So then, through the corpus callosum, the right hemisphere tells about the KEY to the left, and the left speaks to the right about the RING. So, in the end, the person sees KEY RING. But, if the tiny cable, corpus callosum, is cut, no more data is shared between the two hemispheres. So the right hemisphere sees KEY, the left sees RING, and neither sees KEY RING. The convincing hypothesis that results from the outcomes of the split-brain experiment is that if consciousness emerges from the interactions of a group of neurons, then splitting that group can split consciousness. For the intuitive sense, separating consciousness and subsequently slicing feelings, knowledge, emotions, and beliefs seems ludicrous. But the evidence supports the view that both hemispheres may be conscious simultaneously and differently. Furthermore, in one of the split-brain studies, the left hemisphere believes in God, but the right does not. The scientific orthodoxy insists on explaining consciousness as an emerging phenomenon from the neural electrochemical interactions in the brain. And the pursuit of the correlation between the electro-biochemical activities in the brain and the stream of consciousness benefited from various new technologies, such as fMRI and EEG scans. Hoffman is discreet about this hunt for correlation between neurons and consciousness and thinks that the path from correlation to causation is fraught with pitfalls; "if a crowd formed at a train platform, then often a train soon arrives. But crowds don't impel trains to roll in." The train schedule makes the correlation here between the crowd and the train. But for someone observing seems as if a group of people forces the train's arrival. According to Hoffman, a theory that submits that neural activity causes conscious experience should offer mathematical principles that precisely state what action in the brain causes a specific conscious experience. For instance, what brain activity causes the experience of tasting chocolate and does not cause the experience of hearing the thunder? What change in the brain activity changes the experience of tasting chocolate to, say, tasting garlic? Humans have discovered black holes and the evolution of the universe. Still, we don't have any insight into how each specific pattern of the brain's electrochemical activity creates a very different phenomenon: the subjective experience of love, sadness, or hearing the street noise or siren. And even if, as many scientists and philosophers propose, conscience experiences are a mere allusion that rises from the brain process. Huffman argues that we still need the laws and principles that precisely specify these processes, the conscious experiences with which they are identical, and the illusions they generate. A famous belief among those working on the topic of consciousness is that there are limits to human understanding that may prevent us from deciphering the relation between consciousness and brain activity. May the boundaries of our biological structure never enable us to understand consciousness, much like the cat's inability to understand abstract and mathematics. This assumption seems plausible, but listen first to this experiment; people are given a candle, a box of thumbtacks, and a book of matches. They're asked to fasten the candle to the wall so that, when it lits, its wax can't drip on the floor. Most people fail. They tacitly assume that the box must do one thing-hold thumbtack. They don't think of dumping the thumbtacks from the box, fastening it to the wall, and using it as a candle holder. A wrong assumption rather than their limitation impedes them from solving the puzzle. Hoffman supposes that our false beliefs rather than our innate limits can stump our efforts to solve the consciousness puzzle. He proposes that the wrong assumption that precludes us from understanding the relationship between the brain and consciousness assumes we see reality as it is. Some may say that Hoffman is not presenting a new idea; we know that we don't see reality as it is. Physics tells us, for example, that the colors we see as humans are a tiny fraction of the light spectrum that we can't see, such as infrared and ultraviolet. But Hoffman believes that we don't see any objective reality. Yet, although, in the best scenario, we agree that we don't see reality as it is, still, we believe we see some of it. But Huffman goes far beyond and supposes that we do not see any objective reality, and our perception is not a window to objective reality. Instead, it is an interface that hides the objective reality behind the veil of helpful icons. Huffman says we have a long history of being misled by false beliefs; for millennia, we believed that the earth is flat and a geocentric universe, then we realize that our perceptions are fooling us. Let's assume I open my eyes and see a red tomato a meter away. Then, I close my eyes, and the visual experience of the red tomato turns into a shimmering grey; then, I believe that even when my eyes are closed, there is a really red tomato a meter away. Then, when I open my eyes again and see the red tomato, I take it as evidence that the tomato was always there, even when there was no eye to see it or a hand to touch it. But is it possible that I am wrong? By the way, this is an old philosophical question. And Huffman's surprising answer to this question is the subject of this book.
In chapter two, Hoffman discusses beauty on the ground of evolution by natural selection to defend his hypothesis that our perceptions inform us about fitness, not truth or objective reality. In the eighteenth century, David Hume argued that beauty is in the eye of the beholder; beauty is not a quality in the things themself but in the receiver's mind, and each mind catches different beauty. And then Darwin explained beauty as a perception of fitness payoffs, whether an apple on a tree or a person to date. This perception differs from specie to specie, from person to person, and even from time to time. How do we judge human beauty? According to evolutionary psychology, when, for instance, we glance at a face, we unconsciously examine its eyes and score them on a detailed checklist. And what men find attractive about women's eyes differs from what women find attractive about men's eyes. The book brings examples of the perception of beauty from the non-human species, and one is the Male jewel beetles in western Australia. The male from this kind of beetle flies around, looking for the shiny, dimpled, and brown female. Lately, people have been driving through the beetle's habitats and leaving their empty beer bottles in the area, and some of these bottles were shiny, dimpled, and just the right shade of brown to catch the taste of male beetles. The male beetles tried to mate the glassy bottles and more over preferring these bottles over females. Worse than that, some types of ants loiter around the empty bottles waiting for the poor confused beetles and then devour them. So the deceived beetles swayed to extinction, and Australia had to change its beer bottles to save its beetles. Male beetles have mated with females for thousands of years, and we think they should be very precise about their females, but they are not. So why does the beetle male fall in love with a bottle? Some say this may be traced back to the beetle's tiny brain. But, creatures with much bigger brains make similar mistakes. For example, the Alaskan moose have been seen and photographed mating with metal statues of moose. We humans laugh about it, but we have our blockhead history, from sex dolls to sex robots. Huffman states that beauty is the intelligent judgment of complex but mostly unconscious computation. What does that mean? Each time a beetle, moose, or Homo sapiens encounters another member of its species, it automatically examines numerous telltale clues in a fraction of a second. These clues, shaped by eons of evolution, inform the individual about one thing: the potential for reproduction. Is this individual qualified to have and raise healthy offspring? We, of course, won't experience apparent thoughts about this judgment; instead, it will emerge as a feeling that varies between hot and not hot. It is all about the geans' struggle or competition with each other for fitness; the battle is by proxy, and beauty is an ingenious phenotypic device that geans rely on in this battle. If geans get beauty wrong, they tend to go extinct, as happened to the wretched male beetles in Australia when the empty bottle was found more attractive than the female beetle. Geans don't have direct contact in their hunt for reproduction probabilities. They are invisible to each other. The only place geans can see fitness is the phenotypes of bodies and minds that other geans formed and put in their service to fight for fitness. The limbal ring is one of the human eye features in the beauty search. It is a dark ring between the iris and sclera. Huffman brings the example of the Afghan girl, who here picture was on the cover of National Geographic and became the most recognized photograph in the magazine's history, and tried to answer the question: Why does the prominent limbal ring enhance her beauty? The reason, as Huffman believes, is that prominent limbal ring signal health. Diseases can cloud the cornea and make the limbal ring less visible. Also, limbal rings tell about youth; measurements in Huffman's lab found that the thickness of the limbal ring decline with age. Huffman points out that limbal rings signal health and youth, and thus fitness. The data shows that both men and women prefer faces with a clear limbal ring, even if the face is upside down. Through a sequence of experiments, Hoffman's lab found the criteria for the ideal ring; the perfect thickness, opacity, and tapering that makes it most attractive. That means editing your rings can enhance your picture or even use the new technique of makeup applied directly to the eye itself. Of course, this lie will deceive the beholder's genes, but "sometimes the lie is white. Lipstick and eyeliner never hurt a soul." Huffman speaks that the eyes may be windows to the soul, but they are certainly windows to what matters more in evolution: personal and inclusive fitness. Huffman's study of beauty, and evolution by natural selection, in general, is the starting point to answer the book's central question: Do we perceive reality as it is? The answer, as we will see, is counterintuitive. If our senses evolved by natural selection, then spacetime and physical objects, like beauty, inhabit the eye of the beholder to inform about fitness, not truth or objective reality.
Huffman starts chapter three by reviewing several letters exchanged with Francis Crick in the nineties. And Crick was a molecular biologist and neuroscientist who co-discovered DNA structure with James Watson. Crick argues that our perceptions match reality. Most of us may speculate that our vision works like shooting a video with a camera, and we believe a real 3D world exists even one no one looks. But far from the common sense that leads us to this speculation, neuroscience assures that each time we open our eyes, billions of neurons and a third of our brain's computing power are engaged in vision, which is not a matter of recording videos. The eye itself does not see apples or mountains. Instead, the brain constructs our perceptions of objects through 130 million photoreceptors. Each photoreceptor counts the number of light photons and sends reports of these numbers. Just an astonishing array of digits with no apparent meaning, the brain constructs objects such as apples and mountains because the eye itself does not see them. We see a symbolic construction of the world that we don't have direct knowledge of its objects. Francis Crick and most neuroscientists believe that the thing in itself can be the subject of perception; our idea of the sun is symbolic construction, but the sun exists before this construction, and the same vocabulary can describe both. Crick and Huffman agreed that what we see is a symbolic interpretation of the world which we don't have direct knowledge of its objects. Still, Hoffman rejects the hypothesis that our ideas about the sun, red tomatoes, or even neurons correctly describe them. In the late 1970s and early 1980s, neuroscientist David Marr made far-reaching changes in our understanding of the vision. He believed that our perception correctly describes the things -in themselves. This match between perceptions and reality results from a long process of evolution that shaped our perception to match reality. Most perceptual theorists agree that our perceptions are suitable to describe what exists when no one looks. They believe that our internal representations of the outside world match the structure of the objective world. Marr and most vision scientists will claim that if I see a tomato and then close my eyes, the tomato is still there. But could they be wrong? Is it possible there is no tomato if no one looks? Is it possible that we don't see reality as it is? No space and time?
Fitness Beats Truth
In chapter four, Hoffman reviews FBT theory or fitness beats truth theory. In short, the sensory system evolved to enable the organism to see fitness, not the truth. Hoffman's argument contradicts the widespread common understanding that spacetime and physical objects are fundamental realities. Hoffman's claim that spacetime and physical objects are not objective reality is based on the theory of evolution by natural selection. The starting question he asks is whether evolution by natural selection would shape our sensory system to show the true nature of objective reality. He first distinguishes between fitness and truth and claims that natural selection shaped us to see fitness, not truth. Then, he uses mathematics to tell whether our sensory system evolved into seeing the truth and finds that the probability is zero. Anything we see, hear, and test represents fitness but not objective reality. Hoffman argues fitness and truth are two different things; although fitness payoffs depend on the true state of the world, they also depend on the state of the organism. So, for example, hydrogen sulfide at 80ºC in deep water offers big payoffs for the Pompeii worm but hideous death to all but a handful of extremophiles. Let's go back to the Male jewel beetles' example; If evolution shaped the beetles' males to see the truth, they should be accurate about their females, but they are not; they see anything shiny, dimpled, and just the right shade of brown as an attractive female. According to Hoffman, our senses don't lie to us any more than icons on the computer desktop do. So, for example, when the computer interface portrays the bin icon, it does not reveal the truth but is a guide to helpful action. And we will talk more about the computer interface metaphor in the following chapters.
Back to FBT theory, how can perceptions be helpful to survive and reproduce when they are not true? To explain that, in chapter five, Hoffman uses the computer interface, like the desktop or laptop, as a metaphor for the perceptual system. The perceptual interface is shaped by natural selection and varies from specie to specie. Hoffman calls this the interface theory of perception (ITP). Suppose you have a working file on your computer that is blue, rectangular, and in the center of the desktop. The icon's color, shape, and location are not the file's actual color, shape, or location. The file has no color and shape, and the location of its bits in the computer is irrelevant to its icon position on the desktop. The computer desktop job is not showing voltage, magnetic fields, logic gates, software, and binary codes but hides that complexity. Hiding the complexity of the computer's nature is not to shade us but because hiding that nature allows us to complete the task at hand. For example, the computer interface helps us save a picture, edit a file, send an email, and watch a video. Still, it may never reach its destination if you attempt to send an email by understanding the bits, voltage, and codes. Hoffman claims evolution shaped our senses as a user interface that hides objective reality and guides adaptive behavior. The language of space and time, physical objects with shapes, positions, colors, textures, and smells, is the correct language to describe fitness payoffs. Still, it will be the wrong language to describe objective reality. Just as we cannot explain the inner workings of a computer through the language of icons and pixels, we cannot understand objective reality through the language of spacetime and physical objects. If a fire, cliff, busy highway, or poison snack is just an interface icon, why don't you step into the fire, jump off the cliff, or grab the poison snake? Hoffman will argue that evolution has shaped our perceptions to keep us alive, and we had better take them seriously, but not literally. According to Hoffman, if I see a rattlesnake writhing my way, I should take it seriously, but it does not mean that there is something brown and sleek when no one observes. Instead, snakes are icons of our interface that guide adaptive behaviors like fleeing. After all, if we are a group of people and we see a snake will agree that there is a snake. One explanation for this consensus is to accept the intuitive sense that there is a snake. But there is another way to explain it: as members of the same species, we have the same interface; thus, we similarly construct our icons because we have similar needs and similar methods for acquiring fitness payoffs. In the relation between perception and objective reality, Hoffman brings a few examples to prove that there is no such relation. One example is the vanilla molecule. The molecule's chemical formula comprises hydrogen, carbon, and oxygen atoms. No taste experience can accurately describe that molecule. And this is not limited to vanilla, but any other molecule will be impossible to uncover through taste. Tastes, such as vanilla, are shortcuts that inform us about choices, what food to eat and what to avoid, and these choices can mean life or death. If we need to check each atom before we choose what to eat will not be advantageous to our survival. But though our perceptions are not veridical, we still can define illusion. According to Hoffman's ITP theory, the illusion is a perception that fails to guide adaptive behavior since evolution shaped our perceptions to guide adaptive behavior, not to see the truth. The beetle that wooing a bottle suffers an illusion, not because it fails to see the truth. But its perception motivates unfit action: mating with bottles produces no beetles, and in the end, beetles will go extinct. What can we say about the enormous technological developments, from mobile to space rockets? Is it not proof that scientific theory is advancing and getting closer to the objective truth of the world? Hoffman argues that scientific theories are formulated in the language of objects in spacetime and still bound to the interface. Therefore, they can't properly describe reality more than a theory formed in the language of pixels and icons can properly describe a computer.
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