Homo Deus

by Yuval Noah Harari

  You might reply that at least in the case of major decisions such as murdering a neighbour or electing a government, my choice does not reflect a momentary feeling, but a long and reasoned contemplation of weighty arguments. However, there are many possible trains of arguments I could follow, some of which will cause me to vote Conservative, others to vote Labour, and still others to vote UKIP or just stay at home. What makes me board one train of reasoning rather than another? In the Paddington of my brain, I may be compelled to get on a particular train of reasoning by deterministic processes, or I may embark at random. But I don’t ‘freely’ choose to think those thoughts that will make me vote Conservative.

  These are not just hypotheses or philosophical speculations. Today we can use brain scanners to predict people’s desires and decisions well before they are aware of them. In one kind of experiment, people are placed within a huge brain scanner, holding a switch in each hand. They are asked to press one of the two switches whenever they feel like it. Scientists observing neural activity in the brain can predict which switch the person will press well before the person actually does so, and even before the person is aware of their own intention. Neural events in the brain indicating the person’s decision begin from a few hundred milliseconds to a few seconds before the person is aware of this choice.2

  The decision to press either the right or left switch certainly reflected the person’s choice. Yet it wasn’t a free choice. In fact, our belief in free will results from faulty logic. When a biochemical chain reaction makes me desire to press the right switch, I feel that I really want to press the right switch. And this is true. I really want to press it. Yet people erroneously jump to the conclusion that if I want to press it, I choose to want to. This is of course false. I don’t choose my desires. I only feel them, and act accordingly.

  People nevertheless go on arguing about free will because even scientists all too often continue to use outdated theological concepts. Christian, Muslim and Jewish theologians debated for centuries the relations between the soul and the will. They assumed that every human has an internal inner essence – called the soul – which is my true self. They further maintained that this self possesses various desires, just as it possesses clothes, vehicles and houses. I allegedly choose my desires in the same way I choose my clothes, and my fate is determined according to these choices. If I choose good desires, I go to heaven. If I choose bad desires, I am sent to hell. The question then arose, how exactly do I choose my desires? Why, for example, did Eve desire to eat the forbidden fruit the snake offered her? Was this desire forced upon her? Did this desire just pop up within her by pure chance? Or did she choose it ‘freely’? If she didn’t choose it freely, why punish her for it?

  However, once we accept that there is no soul, and that humans have no inner essence called ‘the self’, it no longer makes sense to ask, ‘How does the self choose its desires?’ It’s like asking a bachelor, ‘How does your wife choose her clothes?’ In reality, there is only a stream of consciousness, and desires arise and pass within this stream, but there is no permanent self who owns the desires, hence it is meaningless to ask whether I choose my desires deterministically, randomly or freely.

  It may sound extremely complicated, but it is surprisingly easy to test this idea. Next time a thought pops up in your mind, stop and ask yourself: ‘Why did I think this particular thought? Did I decide a minute ago to think this thought, and only then did I think it? Or did it just arise in my mind, without my permission or instruction? If I am indeed the master of my thoughts and decisions, can I decide not to think about anything at all for the next sixty seconds?’ Just try, and see what happens.

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  Doubting free will is not just a philosophical exercise. It has practical implications. If organisms indeed lack free will, it implies we could manipulate and even control their desires using drugs, genetic engineering or direct brain stimulation.

  If you want to see philosophy in action, pay a visit to a robo-rat laboratory. A robo-rat is a run-of-the-mill rat with a twist: scientists have implanted electrodes into the sensory and reward areas in the rat’s brain. This enables the scientists to manoeuvre the rat by remote control. After short training sessions, researchers have managed not only to make the rats turn left or right, but also to climb ladders, sniff around garbage piles, and do things that rats normally dislike, such as jumping from great heights. Armies and corporations show keen interest in the robo-rats, hoping they could prove useful in many tasks and situations. For example, robo-rats could help detect survivors trapped under collapsed buildings, locate bombs and booby traps, and map underground tunnels and caves.

  Animal-welfare activists have voiced concern about the suffering such experiments inflict on the rats. Professor Sanjiv Talwar of the State University of New York, one of the leading robo-rat researchers, has dismissed these concerns, arguing that the rats actually enjoy the experiments. After all, explains Talwar, the rats ‘work for pleasure’ and when the electrodes stimulate the reward centre in their brain, ‘the rat feels Nirvana’.3

  To the best of our understanding, the rat doesn’t feel that somebody else controls her, and she doesn’t feel that she is being coerced to do something against her will. When Professor Talwar presses the remote control, the rat wants to move to the left, which is why she moves to the left. When the professor presses another switch, the rat wants to climb a ladder, which is why she climbs the ladder. After all, the rat’s desires are nothing but a pattern of firing neurons. What does it matter whether the neurons are firing because they are stimulated by other neurons, or because they are stimulated by transplanted electrodes connected to Professor Talwar’s remote control? If you asked the rat about it, she might well have told you, ‘Sure I have free will! Look, I want to turn left – and I turn left. I want to climb a ladder – and I climb a ladder. Doesn’t that prove that I have free will?’

  Experiments performed on Homo sapiens indicate that like rats humans too can be manipulated, and that it is possible to create or annihilate even complex feelings such as love, anger, fear and depression by stimulating the right spots in the human brain. The US military has recently initiated experiments on implanting computer chips in people’s brains, hoping to use this method to treat soldiers suffering from post-traumatic stress disorder.4 In Hadassah Hospital in Jerusalem, doctors have pioneered a novel treatment for patients suffering from acute depression. They implant electrodes into the patient’s brain, and wire the electrodes to a minuscule computer implanted into the patient’s breast. On receiving a command from the computer, the electrodes use weak electric currents to paralyse the brain area responsible for the depression. The treatment does not always succeed, but in some cases patients reported that the feeling of dark emptiness that tormented them throughout their lives disappeared as if by magic.

  One patient complained that several months after the operation, he had a relapse, and was overcome by severe depression. Upon inspection, the doctors found the source of the problem: the computer’s battery had run out of power. Once they changed the battery, the depression quickly melted away.5

  Due to obvious ethical restrictions, researchers implant electrodes into human brains only under special circumstances. Hence most relevant experiments on humans are conducted using non-intrusive helmet-like devices (technically known as ‘transcranial direct current stimulators’). The helmet is fitted with electrodes that attach to the scalp from outside. It produces weak electromagnetic fields and directs them towards specific brain areas, thereby stimulating or inhibiting select brain activities.

  The American military experiments with such helmets in the hope of sharpening the focus and enhancing the performance of soldiers both in training sessions and on the battlefield. The main experiments are conducted in the Human Effectiveness Directorate, which is located in an Ohio air force base. Though the results are far from conclusive, and though the hype around transcranial stimulators currently runs far ahead of actual achievements, s
everal studies have indicated that the method may indeed enhance the cognitive abilities of drone operators, air-traffic controllers, snipers and other personnel whose duties require them to remain highly attentive for extended periods.6

  Sally Adee, a journalist for the New Scientist, was allowed to visit a training facility for snipers and test the effects herself. At first, she entered a battlefield simulator without wearing the transcranial helmet. Sally describes how fear swept over her as she saw twenty masked men, strapped with suicide bombs and armed with rifles, charge straight towards her. ‘For every one I manage to shoot dead,’ writes Sally, ‘three new assailants pop up from nowhere. I’m clearly not shooting fast enough, and panic and incompetence are making me continually jam my rifle.’ Luckily for her, the assailants were just video images, projected on huge screens all around her. Still, she was so disappointed with her poor performance that she felt like putting down the rifle and leaving the simulator.

  Then they wired her up to the helmet. She reports feeling nothing unusual, except a slight tingle and a strange metallic taste in her mouth. Yet she began picking off the terrorists one by one, as coolly and methodically as if she were Rambo or Clint Eastwood. ‘As twenty of them run at me brandishing their guns, I calmly line up my rifle, take a moment to breathe deeply, and pick off the closest one, before tranquilly assessing my next target. In what seems like next to no time, I hear a voice call out, “Okay, that’s it.” The lights come up in the simulation room…In the sudden quiet amid the bodies around me, I was really expecting more assailants, and I’m a bit disappointed when the team begins to remove my electrodes. I look up and wonder if someone wound the clocks forward. Inexplicably, twenty minutes have just passed. “How many did I get?” I ask the assistant. She looks at me quizzically. “All of them.” ’

  The experiment changed Sally’s life. In the following days she realised she has been through a ‘near-spiritual experience…what defined the experience was not feeling smarter or learning faster: the thing that made the earth drop out from under my feet was that for the first time in my life, everything in my head finally shut up…My brain without self-doubt was a revelation. There was suddenly this incredible silence in my head…I hope you can sympathise with me when I tell you that the thing I wanted most acutely for the weeks following my experience was to go back and strap on those electrodes. I also started to have a lot of questions. Who was I apart from the angry bitter gnomes that populate my mind and drive me to failure because I’m too scared to try? And where did those voices come from?’7

  Some of those voices repeat society’s prejudices, some echo our personal history, and some articulate our genetic legacy. All of them together, says Sally, create an invisible story that shapes our conscious decisions in ways we seldom grasp. What would happen if we could rewrite our inner monologues, or even silence them completely on occasion? 8

  As of 2016, transcranial stimulators are still in their infancy, and it is unclear if and when they will become a mature technology. So far they provide enhanced capabilities for only short durations, and even Sally Adee’s twenty-minute experience may be quite exceptional (or perhaps even the outcome of the notorious placebo effect). Most published studies of transcranial stimulators are based on very small samples of people operating under special circumstances, and the long-term effects and hazards are completely unknown. However, if the technology does mature, or if some other method is found to manipulate the brain’s electric patterns, what would it do to human societies and to human beings?

  People may well manipulate their brain’s electric circuits not just in order to shoot terrorists, but also to achieve more mundane liberal goals. Namely, to study and work more efficiently, immerse ourselves in games and hobbies, and be able to focus on what interests us at any particular moment, be it maths or football. However, if and when such manipulations become routine, the supposedly free will of customers will become just another product we can buy. You want to master the piano but whenever practice time comes you actually prefer to watch television? No problem: just put on the helmet, install the right software, and you will be downright aching to play the piano.

  You may counter-argue that the ability to silence or enhance the voices in your head will actually strengthen rather than undermine your free will. Presently, you often fail to realise your most cherished and authentic desires due to external distractions. With the help of the attention helmet and similar devices, you could more easily silence the alien voices of priests, spin doctors, advertisers and neighbours, and focus on what you want. However, as we will shortly see, the notion that you have a single self and that you could therefore distinguish your authentic desires from alien voices is just another liberal myth, debunked by the latest scientific research.

  Who Are I?

  Science undermines not only the liberal belief in free will, but also the belief in individualism. Liberals believe that we have a single and indivisible self. To be an individual means that I am in-dividual. Yes, my body is made up of approximately 37 trillion cells,9 and each day both my body and my mind go through countless permutations and transformations. Yet if I really pay attention and strive to get in touch with myself, I am bound to discover deep inside a single clear and authentic voice, which is my true self, and which is the source of all meaning and authority in the universe. For liberalism to make sense, I must have one – and only one – true self, for if I had more than one authentic voice, how would I know which voice to heed in the polling station, in the supermarket and in the marriage market?

  However, over the last few decades the life sciences have reached the conclusion that this liberal story is pure mythology. The single authentic self is as real as the eternal Christian soul, Santa Claus and the Easter Bunny. If you look really deep within yourself, the seeming unity that we take for granted dissolves into a cacophony of conflicting voices, none of which is ‘my true self’. Humans aren’t individuals. They are ‘dividuals’.

  The human brain is composed of two hemispheres, connected to each other through a thick neural cable. Each hemisphere controls the opposite side of the body. The right hemisphere controls the left side of the body, receives data from the left-hand field of vision and is responsible for moving the left arm and leg, and vice versa. This is why people who have had a stroke in their right hemisphere sometimes ignore the left side of their body (combing only the right side of their hair, or eating only the food placed on the right side of their plate).10

  There are also emotional and cognitive differences between the two hemispheres, though the division is far from clear-cut. Most cognitive activities involve both hemispheres, but not to the same degree. For example, in most cases the left hemisphere plays a more important role in speech and in logical reasoning, whereas the right hemisphere is more dominant in processing spatial information.

  Many breakthroughs in understanding the relations between the two hemispheres were based on the study of epilepsy patients. In severe cases of epilepsy, electrical storms begin in one part of the brain but quickly spread to other parts, causing a very acute seizure. During such seizures patients lose control of their body, and frequent seizures consequently prevent patients from holding a job or leading a normal lifestyle. In the mid-twentieth century, when all other treatments failed, doctors alleviated the problem by cutting the thick neural cable connecting the two hemispheres, so that electrical storms beginning in one hemisphere could not spill over to the other. For brain scientists these patients were a goldmine of astounding data.

  Some of the most notable studies on these split-brain patients were conducted by Professor Roger Wolcott Sperry, who won the Nobel Prize in Physiology and Medicine for his groundbreaking discoveries, and by his student, Professor Michael S. Gazzaniga. One study was conducted on a teenaged boy. The boy was asked what he would like to do when he grew up. The boy answered that he wanted to be a draughtsman. This answer was provided by the left hemisphere, which plays a crucial part in logical reasoning as well as
in speech. Yet the boy had another active speech centre in his right hemisphere, which could not control vocal language, but could spell words using Scrabble tiles. The researchers were keen to know what the right hemisphere would say. So they spread Scrabble tiles on the table, and then took a piece of paper and wrote on it: ‘What would you like to do when you grow up?’ They placed the paper at the edge of the boy’s left visual field. Data from the left visual field is processed in the right hemisphere. Since the right hemisphere could not use vocal language, the boy said nothing. But his left hand began moving rapidly across the table, collecting tiles from here and there. It spelled out: ‘automobile race’. Spooky.11

  Equally eerie behaviour was displayed by patient WJ, a Second World War veteran. WJ’s hands were each controlled by a different hemisphere. Since the two hemispheres were out of touch with one another, it sometimes happened that his right hand would reach out to open a door, and then his left hand would intervene and try to slam the door shut.

  In another experiment, Gazzaniga and his team flashed a picture of a chicken claw to the left-half brain – the side responsible for speech – and simultaneously flashed a picture of a snowy landscape to the right brain. When asked what they saw, patients invariably answered ‘a chicken claw’. Gazzaniga then presented one patient, PS, with a series of picture cards and asked him to point to the one that best matched what he had seen. The patient’s right hand (controlled by his left brain) pointed to a picture of a chicken, but simultaneously his left hand shot out and pointed to a snow shovel. Gazzaniga then asked PS the million-dollar question: ‘Why did you point both to the chicken and to the shovel?’ PS replied, ‘Oh, the chicken claw goes with the chicken, and you need a shovel to clean out the chicken shed.’12