Intelligence itself is benign. As I argued two chapters ago, unless we purposefully build in selfish drives, motivations, and emotions, intelligent machines will not pose a risk to our survival. Human intelligence, however, is not as benign. The possibility that human behavior might lead to our demise has been recognized for a long time. For example, since 1947 the Bulletin of the Atomic Scientists has maintained the Doomsday Clock to highlight how close we are to making Earth uninhabitable. First inspired by the possibility that a nuclear war and resulting conflagration could destroy Earth, the Doomsday Clock was expanded in 2007 to include climate change as a second potential cause of self-inflicted extinction. Whether nuclear weapons and human-induced climate change are existential threats is debated, but there is no question that both have the potential to cause great human suffering. With climate change, we are past any uncertainty; the debate has mostly shifted to how bad it will be, who will be affected, how quickly it will progress, and what we should do about it.
The existential threats of nuclear weapons and climate change did not exist one hundred years ago. Given the current rate of technological change, we will almost certainly create additional existential threats in the coming years. We need to fight these threats, but if we are to succeed in the long term then we need to look at these problems from a systemic point of view. In this chapter, I focus on the two fundamental systemic risks associated with the human brain.
The first is associated with the older parts of our brain. Although our neocortex endows us with superior intelligence, 30 percent of our brain evolved much longer ago and creates our more primitive desires and actions. Our neocortex has invented powerful technologies that are capable of changing the entire Earth, but the human behavior that controls these world-changing technologies is often dominated by the selfish and shortsighted old brain.
The second risk is more directly associated with the neocortex and intelligence. The neocortex can be fooled. It can form false beliefs about fundamental aspects of the world. Based on these false beliefs, we can act against our own long-term interests.
We are animals, descended from countless generations of other animals. Each and every one of our ancestors was successful in having at least one offspring, which in turn had at least one offspring, and so on. Our lineage goes back billions of years. Throughout this entire stretch of time, the ultimate measure of success—arguably the only one—was preferentially passing one’s genes on to the next generation.
Brains were useful only if they increased the survival and fecundity of an animal possessing one. The first nervous systems were simple; they only controlled reflex reactions and bodily functions. Their design and function were completely specified by genes. Over time, the built-in functions expanded to include behaviors we consider desirable today, such as caring for offspring and social cooperation. But behaviors we look less kindly upon also appeared, such as fighting over territory, fighting for mating rights, forced copulation, and stealing resources.
All built-in behaviors, regardless of whether we think of them as desirable or not, came into being because they were successful adaptations. The older parts of our brain still harbor these primitive behaviors; we all live with this heritage. Of course, each of us lies somewhere along a spectrum of how much we express these old-brain behaviors and how much our more logical neocortex is able to control them. Some of this variation is believed to be genetic. How much is cultural is unknown.
So, even though we are intelligent, our old brain is still here. It is still operating under the rules laid down by hundreds of millions of years of survival. We still fight for territory, we still fight for mating rights, and we still cheat, rape, and trick our fellow humans. Not everyone does these things, and we teach our children the behaviors we want them to exhibit, but a quick look at any day’s news will confirm that, as a species, across cultures and in every community, we haven’t yet been able to free ourselves from these less desirable primitive behaviors. Again, when I refer to a behavior as being less desirable, I mean from an individual or societal point of view. From the perspective of genes, all these behaviors are useful.
On its own, the old brain doesn’t represent an existential risk. The behaviors of the old brain are, after all, successful adaptations. In the past, if, in the pursuit of territory, one tribe killed all the members of another tribe, it didn’t threaten all humans. There were winners as well as losers. The actions of one or a few people were limited to a part of the globe and a part of humanity. Today, the old brain represents an existential threat because our neocortex has created technologies that can alter and even destroy the entire planet. The shortsighted actions of the old brain, when paired with the globe-altering technologies of the neocortex, have become an existential threat to humanity. Let’s look at how this plays out today by examining climate change and one of its underlying causes, population growth.
Human-caused climate change is a result of two factors. One is the number of people who live on Earth and the other is how much pollution each person creates. Both of these numbers are going up. Let’s look at population growth.
In 1960, there were about three billion people on the planet. My earliest memories are from that decade. I don’t recall anyone proposing that the problems the world faced in the 1960s could be solved if only we had twice as many people. Today, the world’s human population is approaching eight billion and continuing to grow.
Simple logic says that the Earth would be less likely to experience some form of human-caused degradation and collapse if there were fewer people. For example, if there were two billion people instead of eight billion, then it is possible that the Earth’s ecosystems could absorb our impact without rapid and radical change. Even if the Earth couldn’t sustainably handle the presence of two billion humans, we would have more time to adjust our behaviors to live in a sustainable way.
Why, then, did the Earth’s population go from three billion in 1960 up to eight billion today? Why didn’t the population stay at three billion, or go down to two billion? Almost everyone would agree that the Earth would be better off with fewer people instead of more. Why isn’t that happening? The answer may be obvious, but it is worth dissecting it a bit.
Life is based on a very simple idea: genes make as many copies of themselves as possible. This led to animals trying to have as many children as possible and to species trying to inhabit as many locales as possible. Brains evolved to serve this most basic aspect of life. Brains help genes make more copies of themselves.
However, what is good for genes is not always good for individuals. For example, from a gene’s point of view, it is fine if a human family has more children than it can feed. Sure, in some years children may die of starvation, but in other years they won’t. From a gene’s perspective, it is better to occasionally have too many children than too few. Some children will suffer horribly, and parents will struggle and grieve, but genes don’t care. We, as individuals, exist to serve the needs of genes. Genes that lead us to have as many children as possible will be more successful, even if that sometimes leads to death and misery.
Similarly, from a gene’s perspective, it is best if animals try to live in new locations, even if these attempts often fail. Say a human tribe splits and occupies four new habitats, but only one of the splinter groups survives while the other three struggle, starve, and ultimately die out. There will be much misery for the individual humans but success for the gene, as it now occupies twice as much territory as before.
Genes don’t understand anything. They don’t enjoy being genes, and they don’t suffer when they fail to replicate. They are simply complex molecules that are capable of replication.
The neocortex, on the other hand, understands the larger picture. Unlike the old brain—with its hardwired goals and behaviors—the neocortex learns a model of the world and can predict the consequences of uncontrolled population growth. Thus, we can anticipate the misery and suffering that we will endure if we continue to let the number of people on Earth grow. So why aren’t we collectively lowering the population? Because the old brain is still in charge.
Recall the example of a tempting piece of cake that I mentioned in Chapter 2. Our neocortex may know that eating cake is bad for us, that it can lead to obesity, disease, and early death. We may leave the house in the morning resolved to eat only healthy food. Yet, when we see and smell a piece of cake, we often eat it anyway. The old brain is in control, and the old brain evolved in a time when calories were hard to come by. The old brain does not know about future consequences. In the battle between the old brain and the neocortex, the old brain usually wins. We eat the cake.
Since we have difficulty controlling our eating, we do what we can. We use our intelligence to mitigate the damage. We create medical interventions, such as drugs and surgeries. We hold conferences on the epidemic of obesity. We create campaigns to educate people about the risks of bad food. But even though, logically, it would be best if we just ate better, the fundamental problem remains. We still eat cake.
Something analogous is happening with population growth. We know that at some point we will have to stop our population’s growth. This is simple logic; populations cannot grow forever, and many ecologists believe ours is already unsustainable. But we find it difficult to manage our population because the old brain wants to have children. So instead we have used our intelligence to dramatically improve farming, inventing new crops and new methods to increase yield. We have also created technologies that allow us to ship food anywhere in the world. Using our intelligence, we have achieved the miraculous: we have reduced hunger and famine during a period when the human population has almost tripled. However, this can only go on for so long. Either population growth stops or sometime in the future there will be great human suffering on Earth. That is a certainty.
Of course, this situation is not as black-and-white as I have portrayed. Some people logically decide to have fewer or no children, some may not have the education to understand the long-term threats of their actions, and many are so poor that they rely on having children for survival. The issues related to population growth are complex, but if we step back and look at the big picture, we see that humans have understood the threat of population growth for at least fifty years, and in that time our population has nearly tripled. At the root of this growth are old-brain structures and the genes they serve. Fortunately, there are ways that the neocortex can win this battle.
The odd thing about overpopulation is that the idea of having a smaller human population isn’t controversial, but talking about how we might achieve it from where we are today is socially and politically unacceptable. Perhaps we recall China’s largely decried one-child policy. Perhaps we unconsciously associate reducing the population with genocide, eugenics, or pogroms. For whatever reason, purposefully aiming for a smaller population is rarely discussed. Indeed, when a country’s population is declining, such as in Japan today, it is considered an economic crisis. It is rare to hear Japan’s shrinking population described as a role model for the rest of the world.
We are fortunate that there is a simple and clever solution to population growth, a solution that does not force anyone to do anything they don’t want to do, a solution that we know will reduce our population to a more sustainable size, and a solution that also increases the happiness and well-being of the people involved. But it is a solution that many people object to nonetheless. The simple and clever solution is to make sure every woman has the ability to control her own fertility and is empowered to exercise that option if she wants to.
I call this a clever solution because, in the battle between the old brain and the neocortex, the old brain almost always wins. The invention of birth control shows how the neocortex can use its intelligence to get the upper hand.
Genes propagate best when we have as many offspring as possible. The desire for sex is the mechanism that evolution came up with to serve the genes’ interests. Even if we don’t want more children, it is difficult to stop having sex. So, we used our intelligence to create birth-control methods that let the old brain have as much sex as it wants without creating more children. The old brain is not intelligent; it doesn’t understand what it is doing or why. Our neocortex, with its model of the world, can see the downsides of having too many children, and it can see the benefits of delaying starting a family. Instead of fighting the old brain, the neocortex lets the old brain get what it wants but prevents the undesirable end result.
Why, then, is there sustained resistance to empowering women? Why do many people oppose equal pay, universal day care, and family planning? And why do women still find obstacles to attaining equal representation in positions of power? By almost every objective measure, empowering women will lead to a more sustainable world with less human suffering. From the outside looking in, it seems counterproductive to fight against this. We can blame the old brain and viral false beliefs for this dilemma. This brings us to the second fundamental risk of the human brain.
The neocortex, despite its amazing abilities, can be fooled. People are easily fooled into believing basic things about the world that are false. If you have false beliefs, then you might make fatally bad decisions. It can be especially bad if these decisions have global consequences.
I had my first exposure to the quandary of false beliefs in grade school. As I pointed out earlier, there are many sources of false beliefs, but this story relates to religions. One day during recess at the beginning of the school year, a group of about ten children gathered in a circle on the playground. I joined them. They were taking turns saying what religion they belonged to. As each kid stated what he or she believed, the other kids joined in to say how that religion differed from their religion, such as what holidays they celebrated and what rituals they practiced. The conversation consisted of statements such as, “We believe what Martin Luther said and you don’t.” “We believe in reincarnation, which is different than what you believe.” There was no animosity; it was just a bunch of young children playing back what they had been told at home and sorting through the differences. This was new to me. I was raised in a nonreligious home and had never before heard descriptions of these religions or many of the words the other kids were saying. The conversation focused on the differences in their beliefs. I found this unsettling. If they believed different things, then shouldn’t we all be trying to figure out which beliefs were right?
As I listened to the other kids talk about the differences in what they believed, I knew that they couldn’t all be right. Even at that young age I had a deep sense that something was wrong. After everyone else had spoken, I was asked what my religion was. I answered that I wasn’t sure, but I didn’t think I had a religion. This created quite a stir, with several kids stating it wasn’t possible. Finally, one kid asked, “Then what do you believe? You have to believe in something.”
That playground conversation made a profound impression on me; I have thought about it many times since. What I found unsettling was not what they believed—rather, it was that the kids were willing to accept conflicting beliefs and not be bothered by it. It was as if we were all looking at a tree and one kid said, “My family believes that is an oak tree,” another said, “My family believes it is a palm tree,” and yet another said, “My family believes it isn’t a tree. It’s a tulip”—and yet no one was inclined to debate what the correct answer was.
Today I have a good understanding of how the brain forms beliefs. In the previous chapter, I described how the brain’s model of the world can be inaccurate and why false beliefs can persist despite contrary evidence. For review, here are the three basic ingredients:
1. Cannot directly experience: False beliefs are almost always about things that we can’t directly experience. If we cannot observe something directly—if we can’t hear, touch, or see it ourselves—then we have to rely on what other people tell us. Who we listen to determines what we believe.
2. Ignore contrary evidence: To maintain a false belief, you have to dismiss evidence that contradicts it. Most false beliefs dictate behaviors and rationales for ignoring contrary evidence.
3. Viral spread: Viral false beliefs prescribe behaviors that encourage spreading the belief to other people.
Let’s see how these attributes apply to three common beliefs that are almost certainly false.
1. Cannot directly experience: No individual can directly sense whether vaccines cause autism; this requires a controlled study with many participants.
2. Ignore contrary evidence: You have to ignore the opinion of hundreds of scientists and medical personnel. Your rationale might be that these people are hiding the facts for personal gain or that they are ignorant of the truth.
3. Viral spread: You are told that by spreading this belief you are saving children from a debilitating condition. Therefore, you have a moral obligation to convince other people about the danger of vaccines.
Believing that vaccinations cause autism, even if it leads to the death of children, is not an existential threat to humanity. However, two common false beliefs that are existential threats are denying the danger of climate change and belief in an afterlife.
1. Cannot directly experience: Global climate change is not something individual people can observe. Your local weather has always been variable, and there have always been extreme weather events. Looking out your window day to day, you cannot detect climate change.
2. Ignore contrary evidence: Policies to fight climate change harm the near-term interests of some people and their businesses. Multiple rationales are used to protect these interests, such as that climate scientists are making up data and creating scary scenarios just to get more funding, or that scientific studies are flawed.
3. Viral spread: Climate-change deniers claim that policies to mitigate climate change are an attempt to take away personal freedoms, perhaps to form a global government or benefit a political party. Therefore, to protect freedom and liberty, you have a moral obligation to convince others that climate change is not a threat.
Hopefully it is obvious why climate change represents an existential risk to humanity. There is the possibility that we could alter Earth so much that it becomes uninhabitable. We don’t know how likely this is, but we do know that our nearest neighboring planet, Mars, was once much more like Earth and is now an unlivable desert. Even if the possibility that this could happen to Earth is small, we need to be concerned.
Belief in an afterlife has been around for a very long time. It seems to occupy a persistent niche in the world of false beliefs.
1. Cannot directly experience: No one can directly observe the afterlife. It is by nature unobservable.
2. Ignore contrary evidence: Unlike the other false beliefs, there are no scientific studies that show it isn’t true. Arguments against the existence of an afterlife are based mostly on lack of evidence. This makes it easier for believers to ignore claims that it does not exist.
3. Viral spread: Belief in the afterlife is viral. For example, a belief in heaven says your chance of going to heaven will increase if you try to convince others to believe in it as well.
Belief in an afterlife, on its own, is benign. For example, belief in reincarnation provides an incentive to live a more considerate life and seems to pose no existential risks. The threat arises if you believe that the afterlife is more important than the present life. At its extremes, this leads to the belief that destroying the Earth, or just several major cities and billions of people, will help you and your fellow believers achieve the desired afterlife. In the past, this might have led to the destruction and burning of a city or two. Today, it could lead to an escalating nuclear war that could make Earth unlivable.
This chapter is not a comprehensive list of the threats we face, and I did not explore the full complexity of the threats that I did mention. The point I want to make is that our intelligence, which has led to our success as a species, could also be the seed of our demise. The structure of our brain, composed of an old brain and the neocortex, is the problem.
Our old brain is highly adapted for short-term survival and for having as many offspring as possible. The old brain has its good side, such as nurturing our young and caring for friends and relatives. But it also has its bad side, such as antisocial behavior to garner resources and reproductive access, including murder and rape. Calling these “good” and “bad” is somewhat subjective. From a replicating gene’s point of view, they are all successful.
Our neocortex evolved to serve the old brain. The neocortex learns a model of the world that the old brain can use to better achieve its goals of survival and procreation. Somewhere along the evolutionary path, the neocortex gained the mechanisms for speech and high manual dexterity.
Language enabled the sharing of knowledge. This of course had huge advantages for survival, but it also sowed the seeds of false beliefs. Until the advent of language, the brain’s model of the world was limited to only what we personally could observe. Language allowed us to expand our model to include things we learn from others. For example, a traveler might tell me that there are dangerous animals on the far side of a mountain—a place I have never been—and therefore extend my model of the world. However, the traveler’s story might be false. Perhaps there are valuable resources on the far side of the mountain that the traveler does not want me to know about. In addition to language, our superior manual dexterity enabled the creation of sophisticated tools that include globe-spanning technologies that we increasingly rely on to support the large human population.
Now we find ourselves facing several existential threats. The first problem is that our old brain is still in charge and prevents us from making choices that support our long-term survival, such as reducing our population or eliminating nuclear weapons. The second problem is that the global technologies we have created are vulnerable to abuse by people with false beliefs. Just a few people with false beliefs can disrupt or misuse these technologies, such as by activating nuclear weapons. These people may believe that their actions are righteous and that they will be rewarded, perhaps in another life. Yet, the reality is that no such rewards would occur, while billions of people would suffer.
The neocortex has enabled us to become a technological species. We are able to control nature in ways that were unimaginable just one hundred years ago. Yet we are still a biological species. Each of us has an old brain that causes us to behave in ways that are detrimental to our species’s long-term survival. Are we doomed? Is there any way out of this dilemma? In the remaining chapters, I describe our options.