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INTRODUCTION - WE NEED SCIENCE,  AND WE NEED IT NOW

We humans can be justifiably proud of our brains. No other species has ever had such large brains and so much intelligence. But there is a major problem. Our brains evolved. The brains of our most successful ancestors were not necessarily the ones that understood the truth but the ones that allowed their possessors to prevail in the struggle for existence. As a result, our brains did not evolve to reason but to rationalize, or to see the truth but to create it. Our brains are the playthings of bias and illusion. We use our brains to manipulate others and to deceive ourselves. We often see what we want to see rather than what is really there. All of us.

Illusion and bias are not necessarily bad things. Illusion and bias can be simple and useful. Without these illusions and biases, our brains might be overwhelmed by the complexity of the world. Illusions and biases have allowed our brains to make quick decisions in order for us to survive a sudden threat or to take advantage of a sudden opportunity. An attack by a predator or an enemy is not the best time for rational thought. Our ape brains have been immensely successful in large measure because they can make profitable use of reality and truth but are not constrained by them.

Our biased and deluded brains served us well enough in the past. We did not need to understand the truth so long as we could be successful in the game of evolution. But today, our biases and illusions put us at risk of worldwide catastrophe. We are drowning in yottabytes of information. We do not need more information but a new way of thinking that will liberate our minds from bias and illusion.

Some of the mistakes created by our biased brains affect us only individually. Mistaking correlation for causation can make us waste time and money on health fads that are illusions. But other mistakes that we make collectively can endanger the whole world. Our species is the victim of its own success, and now we have overrun the earth. Every natural habitat, even those we have set aside as parks and reserves, has been altered by our presence and our economic and political activities. Errors made by one individual, one corporation, or one nation can now affect the whole world. Today, all individuals and all countries and all economies are so interconnected that if one group acts like cavemen, they can drag much of the rest of the world down with them. They can be religious extremists trying to wage holy war, or they can be executives of “too big to fail” corporations who use misinformation to increase their profits, or they can be politicians who create their own “facts” in order to win campaigns, and their effects will be felt worldwide. With over seven and a half billion people in the world, there is no room for delusion anymore. Having an ape brain couldn’t happen at a worse time. Illusions and biases served us well in the past, but today they have brought us to the brink of disaster.

One example of how our brains mislead us is the illusion of the cornucopia of nature. It just seems natural to assume that the world is big enough to supply all of our desires and absorb all of our wastes. Maybe it was like that back in the Stone Age. When a caveman threw bones away—“away” meaning outside the camp—the great maw of nature could decompose them. But there are now over seven billion of us, each of us using immense amounts of material and energy and generating toxic wastes. There is no such place as “away” where our wastes can be safely dumped.

Perhaps the most important example of this illusion is global climate change, a topic that I will revisit repeatedly in this book. You can’t see global warming. You have to deduce it from evidence. All you can see is weather; you can’t see climate. Climate is the long-term and broad-scale average of weather. As Mark Twain is reported to have said, climate is what you expect, weather is what you get. Climate is the weather you expect to see in an “average year.” But as the old farmer said, he’d been farming for forty years and had only seen two average years.

We can get the answer to almost any question with just a few keystrokes and the swoop of a computer mouse or the swipe of the screen. You would think that having all of this information at our fingertips would make it easier to find the truth. But this is not the case, for several reasons.

One reason that more information does not lead to a better understanding of the world is that, no matter how much information we have, we can only think about one thing at a time. For a moment, it seems we can take hope in the prodigious capacity of the human brain. Our brains are more complex than any computer. ... But your conscious mind can only pay attention to one thing at a time, no more and no less than a Cro-Magnon hunter-gatherer. You could say that, in this sense, nothing has changed much in the last twenty thousand years.

Another reason that more knowledge does not lead to greater understanding is that, as explained above, the human mind does not look for truth in data but rationalizes it—no matter how many or how few data there are. The easiest thing for our brains to do, when overloaded with information, is to pay attention only to the information that agrees with what we already believe. We have, at our fingertips, troves of information that can free us from our ancient biases, but instead we use this information selectively to reinforce our biases. Perversely, we become more mistaken when we have access to more information.

And not only do we use our brains to deceive others, but we also use our brains to deceive ourselves. Our brains take the data of reality and alter our perceptions to create self-deception, as explained by Robert Trivers. On the bad side, by actually believing the false things that we claim to be true, we become more convincing liars. On the not-so-bad side, by actually believing false things, we can delude ourselves into being happy despite unalterably dismal circumstances. Either way, believing false things can sometimes make us more successful in the evolutionary struggle. And we have to really believe them, not just pretend to. Our brains did not evolve just to rationalize but also to believe that rationalization is reason. Our brains are the amphitheaters of delusion.

We do not need more information about the world. What we need desperately is some way to escape the biases and illusions created by our evolved brains. We need some good news, and we need it now.

But there is good news. This way of thinking already exists. It is the scientific method. Although science has existed in its modern form for only a few centuries, and although most people in the world do not avail themselves of it, science has led to immense breakthroughs in understanding the world. In just a few centuries, we have come to understand the universe, the earth, and ourselves as we never could, and never could imagine, before.

To save ourselves and the world, do we all have to become scientists? This cannot happen, and if it had to, there would be no hope for any of us. Fortunately—and this news is good enough that you can put it on a placard on your wall—you don’t have to be a scientist to use the scientific method. The scientific method is based on mental processes that come naturally to all of us. Most people realize that using “the process of elimination” is just “common sense.” We have an instinct for science, just as we also have biases and illusions. The scientific way of thinking is lurking in our minds, if we can just give it a chance to emerge. The first purpose of this book, then, is to convince you that we desperately need to think scientifically—not just scientists but also all of us. ...

The second purpose of the book is to show you that the scientific way of thinking is not only instinctual but is also surprisingly simple. It is something that anybody can do. Scientific thinking is basically just organized common sense. The hard part is not the science itself but keeping our biases and illusions out of it. I am a scientist and a science educator, and I want to help you get started on the journey of science.

Here is the way we can think scientifically. First, we create a statement about cause and effect, a claim about how something works. We call such a statement a hypothesis. Second, we gather evidence that tests the hypothesis. The evidence must be something that is accessible to anyone (external), not just to the person who makes the claim (internal). This evidence will allow us to determine that the hypothesis is true, that it is false, or that we do not yet know. Third. . .

There is no third. That’s it. That’s science. We test claims by means of evidence. The hypothesis, if it withstands the test, makes sense of an otherwise confused mass of facts. One hypothesis can lead to another, with the eventual result that a whole framework of hypotheses—now called a theory—helps make sense not just of a set of facts but also of the whole world.

But suppose we reach the wrong conclusion. No problem. Since the evidence is external, someone else can come along and present better evidence, which may lead to a different conclusion. In contrast, faith is an internal experience. Many people cling to religious beliefs in the absence of, or even in opposition to, external evidence. But science is external. Science is public. What one person claims, another can test.

Yes, the scientific method is liberating, all right, but it liberates your mind by constraining it. Your mind is free to float untrammeled through all of the clouds and rapids and cliffs of bias and illusion. In order to make your mind seek the truth, you have to keep it from running off in other directions. Think of an ox dragging a cart through the mud. The ox could go in any direction, leaving the cart in the mud. But the yoke constrains the movement of the ox. Science is that yoke: it allows the ox (your mind) to pull the cart of knowledge forward through the mud of confusion. ...

There is more good news. Not only can any normal human being participate in scientific thinking, but also every normal human being begins childhood with that ability. The tiniest infant looks around and observes everything, first the nearby things such as his mother on which he can focus his eyes, and, later, things that are farther away. Although an infant is also subject to inchoate forms of bias and illusion, the infant spends most of his time applying the scientific method to understanding the world. What happens if I push the plate to the edge of the tray? How do I tell which foods are yummy and which are yucky? What happens if I run into a wall? What happens if I scream? And there is more. Children are curious about not just the room and the toys but also about what we call the natural world—trees and birds and rocks. It is only later that an older child may develop the attitude that the natural world is boring. ...

There is even more good news. Not only can the scientific method lead our minds, appropriately constrained, to find the truth, and not only is the scientific method based on an instinctual process, but science can also lead us into a world of beauty. It does so in several ways. Consider these examples.

• First, there is a deep sense of beauty in knowing that the world makes sense. The world is not what Carl Sagan called, referring to the non-scientific view of the universe, a “demon-haunted world” in which anything can happen any time based on the whim of a deity.

• Second, there is beauty in knowing that there is something we might be able to do about our problems. Before we knew that germs caused many diseases, there was not much we could do about them. But now we have, within a couple of years of its first emergence, identified the Zika virus and we know what it does and how it does it. It is not a pretty picture, but our knowledge allows us at least a chance of slowing down its spread and dealing with its consequences.

• And finally, science allows us to begin recognizing the diversity around us. To someone who has never studied trees, a tree is a tree is a tree. But once you begin to study trees, the world becomes so much more interesting because you notice how many kinds there are and how each one of them is a little different in the way it functions in the natural world. Cottonwoods grow fast and die young; oaks grow slowly and die old: once you realize this, a forest is no longer a backdrop but is, in itself, an interesting story.

Our brains evolved to rationalize, but the ability to reason is one of the components of our ape-brain process of rationalization. And when you grasp this simple truth, you are ready to begin thinking scientifically. Nor do you have to believe everything every scientist says as if it is handed down by God, any more than you have to believe everything a politician or a preacher says. You can apply the scientific method to everything and draw your own conclusions. This is perhaps the most exhilarating liberation of which the human mind is capable.

The scientific method is organized common sense. This sounds simple enough. But then it gets complicated. In order to test hypotheses, scientists sometimes have to do absurdly beautiful experiments that make you laugh and then make you think. And it is difficult to deal with bias and illusion. Scientists have to go through a lot of effort, and spend a lot of money, to design experiments that avoid bias and illusion, not only on the part of the experimenter but of the experimental subject as well.

Bias and illusion influence even the very process of measurement itself: how accurately do we measure something, and how big of a sample do we need?

• Our brains tend to see straight lines while nature throws us curves. This is particularly important with the nonlinear economies of scale and threshold values. Even the explosion of evolution and the death of Mars were nonlinear processes.

• Our brains see everything as categories (often just two) while in nature most of what we see is continuous variation.

• Our brains see everything as simple cause and effect while in nature an effect can also be a cause, and an effect can have multiple causes.

• Our minds have the bias of agency: that is, when something happens, an intelligence must have deliberately caused it to happen. Because we are intelligent, we see intelligence everywhere. How can you tell whether an animal is intelligent or not?

• You might be perfectly capable of making measurements, but if the measurements do not represent a fair sample of the diversity of reality, or are in fact measuring something other than what you think they are, they are invalid and misleading.

• Our brains have a confirmation bias in which we literally see what we expect to see rather than what’s really out there.

Science can liberate us from the errors to which even the best human brain is vulnerable. But it has also generated some important Big Ideas that have transformed our whole view of the universe and ourselves. Science is very different from religion, which appears to be a human instinct. Finally, knowing what we know about the world (about everything from global warming to the dangers of tobacco), we scientists cannot sit silently and let people who have it all wrong mess up this beautiful and, as far as we know, unique world. And this leads us on a beautiful venture.

Join me in exploring how the process of science liberates us from illusion and bias. Come laugh with me at the creative ways in which scientists find creative ways to test their hypotheses. And come and see that the scientific way of thinking is not completely different from the common sense and the creativity that we have always known and loved.