I love riddles, and I admire the greatest unsolved mystery of science, perhaps because it affects me. This is a mystery about who we are, and I could not stay away. The riddle is this: What is the connection between your brain and your conscious experience, such as the taste of chocolate or how you feel velvet with your fingertips?
This mystery is not new. In 1868, Thomas Huxley wrote: "How something as wonderful as a state of consciousness manifests itself as a result of irritation of the nervous tissue is just as inexplicable as the appearance of a genie after Aladdin rubbed a lamp." Huxley knew that brain activity and conscious experience were interconnected, but he did not know how. For the science of his day, it was a real mystery. Over the years, science has learned a lot about brain activity, but the relationship between brain activity and conscious experience is still a mystery. Why? Why haven't we moved on? So, some experts believe that we cannot solve this problem because we lack the necessary concepts and intelligence. We don't expect monkeys to solve the problem of quantum mechanics, so we shouldn't expect our species to solve this problem. And I disagree. I am more optimistic. I think we just made a false assumption. Once we figure it out, we can fix the problem. Today I would like to tell you about this assumption, why it is false and how to deal with it.
Let's start with the question: do we see reality as it is? I open my eyes and I see what I can describe as a red tomato located a meter away from me. As a result, I come to the conclusion that this is reality, and there is a red tomato a meter away from me. Then I close my eyes and see only a gray field, but does this red tomato actually continue to exist in reality? I think so, but it may well be that I am wrong? Am I misinterpreting the nature of my perception?
We have misinterpreted our reality before. We thought the Earth was flat because it looked like that. Pythagoras proved that we were wrong. Then we thought that the Earth is the center of the universe, and also because it looked like that. Copernicus and Galileo proved that we were wrong.
Then Galileo wondered: maybe we misinterpret reality only in this way. He wrote: “I think that taste, smell, color and so on are within our consciousness. Therefore, if all living beings were removed, then all these qualities would also be destroyed."
This is an interesting statement. Could Galileo be right? Can we interpret our perception of reality so badly? What will modern science say about this?
So neuroscientists will tell us that about a third of the cerebral cortex is involved in vision. When we just open our eyes and look around the room, billions of neurons and trillions of synapses are at work.
It's a little surprising because we didn't think about it that way, we thought our vision works like a camera. That we just get a picture of what reality looks like. Only part of the vision works like a camera: there is a lens in the eye that focuses the image onto the back of the eye, where 130 million photoreceptors are located, so the eye is a 130 megapixel camera. But this does not explain why then billions of neurons and trillions of synapses are needed, taking part in vision. What are these neurons doing here?
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Neuroscientists say they create in real time all the shapes, objects, colors, and movements that we see. This is similar to how we take a snapshot of a room, but in reality we are recreating everything we see. We are not building a whole world at once. We create what we need at a certain moment.
There are many pretty compelling demonstrations of how we create what we see. I'll show you two of them. In this example, you see some red discs with cut-out pieces, but if I rotate these discs a little, you will see a 3D cube appear on the screen. The screen is, of course, flat, but we see a three-dimensional cube. This is what completes our perception.
In the following example, we see glowing blue stripes with rather jagged edges moving across the dot field. In fact, the points are not moving. I just change the color of the dots from blue to black or from black to blue. I do this quickly, so your visual system creates luminous blue stripes with jagged edges and movement. There are many more examples, but only these two illustrate how you create what you see.
But neuroscientists have gone further. They say we are reconstructing reality. When I opened my eyes and described what I saw - a red tomato, what I saw was actually an exact reconstruction of the properties of a real red tomato, which would have existed if I had not looked at it.
Why do neuroscientists claim that we do not just create, but reconstruct? So the standard explanation is evolution. Those of our ancestors who looked more closely had a competitive advantage over those who looked less closely, so they had a better chance of passing it on through genes. We are the descendants of those who looked more closely, and we can be sure that in the ordinary case our perception is accurate. You can read this in any textbook. One textbook claims, for example, that "From an evolutionary perspective, vision is useful precisely because it is so accurate." So the idea is that accurate perception is the best perception. It gives you the edge in your struggle to survive.
Is everything right now? Is this the correct interpretation of the theory of evolution? So first, let's look at a couple of examples from nature.
Australian woodworm beetle of unusual color - corrugated, glossy and brown. Females cannot fly. Males fly in search of females, of course. When he finds a female, he goes down and they mate. Another species found in the Australian bush is Homo sapiens. The males of this species have large brains that they use to hunt cold beer. (Laughter) When he finds beer, he drinks it and sometimes throws the bottle in the bush. It turns out that these bottles are corrugated, glossy, and the same shade of brown as the color of these beetles. Males fly over these bottles in an attempt to mate. They lose interest in real females. A classic case when men traded women for a bottle. (Laughter) (Applause) This species is almost extinct. In Australia, bottles had to be redesigned to save bugs.(Laughter) Males have been successfully finding females for thousands, perhaps millions of years. They seem to have seen reality as it is, but obviously they haven't. Evolution gave them a clue. The female is something corrugated, glossy and brown. And the bigger it is, the better. (Laughter) Even as the males circled over the bottle, they never knew they were making a mistake.
Now, you can say that beetles are very simple creatures, where do they care about mammals. Mammals don't rely on clues. Well, I'm not going to focus on this, but you get the point. (Laughter)
This raises an important technical question: Does natural selection give us the advantage of seeing reality as it is? Fortunately, we don't have to wave our hands and guess: evolution is a mathematically accurate theory. We can use an evolutionary equation to test this. We can force different organisms to compete in an artificial environment, and then see which ones survive and grow, and which sensory systems are more suitable for this.
Fitness is a key concept in these equations. Let's take a look at this steak: What does this steak do for the animal's fitness? A hungry lion will eat it and thus improve its fitness. For a fed lion ready to mate, this steak will do nothing. A steak will not improve the fitness of a rabbit in any condition. So fitness also depends on reality as it is, yes, but also on the organism, its state and its actions. Fitness is not the same as reality as it is, and that fitness, not reality as it is, is central to the equation.
In my laboratory, we have run hundreds of thousands of evolutionary tests with many different randomly selected environments and organisms that compete for resources in those environments. Some organisms saw all of reality, others saw only part of reality, and others did not see any reality at all. There was only fitness. Who did win?
I do not want to upset you, but the perception of reality disappears. In almost all tests, organisms that did not see any reality, but were tuned in to fitness, destroyed all organisms that perceived reality. As a result, evolution is not conducive to true or accurate perception. This perception of reality simply disappears.
This is amazing. How can it be that not seeing the world gives you a survival advantage? This is a bit counterintuitive. But remember the beetles. The beetles have survived for thousands, possibly millions of years using simple tricks. What the evolutionary equation will tell us about all organisms, including ourselves, in the same boat as the beetles. We do not see reality as it is. We use clues to survive.
Until now, we need the help of our intuition. How can it not be helpful to perceive reality as it is? Fortunately, we have a fitting metaphor for comparison: your computer's desktop. Imagine this blue icon is your TED talk file. So, the icon is blue and rectangular and it is located in the lower right corner of the desktop. Does this mean that the text file itself on the computer is blue, rectangular and located in the left corner of the screen? Of course not. Nobody thought that this distorted the purpose of the interface. But the icon is not here to represent the reality of your computer. In fact, she is here to hide this reality. I don't want to know anything about these diodes and resistors, and all these megabytes of software. If you had to deal with all this,then you would never be able to write this text file, or edit your photo. So the idea is that evolution has given us an interface that hides reality and allows us to adjust. Space and time is how you perceive them now, on your "desktop". Physical objects are just icons on the desktop.
But there are obvious objections. Hoffman, if you think the 321 km / h train is just an icon on your desktop, why don't you step under it? And after you die along with your theory, we learn that the train is more than an icon. Well, I would not throw myself in front of a train for the same reason why I would not carelessly move the icon to the trash can: not only because I will delete the icon, the file is not literally blue and rectangular, but still I I will take this seriously. I could lose weeks of work. Likewise, evolution created us from perceptual symbols to keep us alive. We should take this seriously. If you see a snake, don't pick it up. If you see a cliff, do not jump off it. We are made to keep us safeand took life seriously. But this does not mean that we should take everything literally. This is a logical error.
Another objection: this is nothing new. Physicists have long told us that the metal of which the train is made looks strong, but in reality it is empty space with microscopic particles inside. This is nothing new. Well, not quite. It's like saying that I know that the blue icon on the desktop doesn't really exist, but if I pull out my magnifying glass and take a closer look, I see little pixels, which is what actually exists. Well, not true - you're still on your desktop, and that makes sense. These microscopic particles exist in space and time: they are still on the user interface. I am telling you about even more radical things than physics.
Finally, we could imagine that we are all seeing a train, although none of us build trains. But remember this example. In this example, we can all see a cube, but the screen is flat, so the cube you see is the cube you created. We all see the cube, because we all, each of us, builds the cube that we see. It's the same with the train. We all see the train, because each of us sees the train that we have built, and it all fits to any physical object.
We tend to think that perception is like a window into reality as it is. Evolutionary theory tells us that we misinterpret our perceptions. Instead, reality is more like a 3D desktop designed to hide all the complexity of the real world and helps us to adapt. The space as you perceive it is your desktop. Physical objects are just icons on the desktop.
We used to think that the Earth is flat because it looks like that. Then we thought that the Earth was the center of the universe because it looked like this. We were wrong. We misinterpreted our perception. We now believe that space, time and objects are presented as they are in reality. The theory of evolution tells us that we were wrong again. We misinterpret the content of our perceptual experience. Something exists when you are not looking at it, but it is not space, time, or physical objects. We find it difficult to give up time, space and objects, as well as beetles from bottles. Why? Because we are blind to our own blindness. But we have an advantage over beetles: science and technology. Looking through lenses and telescopes, we found that the Earth is not the center of the universe, when looking through the lenses of the theory of evolution,we have found that space, time and objects are not the basis of reality. When I got a perceptual experience looking at a red tomato, I interacted with reality, but this reality is not a red tomato, or even anything like this tomato. Likewise, when I had a perceptual experience describing a lion or a steak, I interacted with reality, but that reality is not a lion or a steak. But the trick is that when I had a perceptual experience, describing the brain or neurons, I interact with reality, but reality is not a brain or neurons, and not a bit like a brain or neurons. Reality, whatever it may be, is the real source of causes and actions in the world - this is not a matter of the brain or neurons. The brain and neurons do not have the power to change reality. They do not create any perceptual experience,and are not the reason for our actions. The brain and neurons are a species-specific set of symbols, a gimmick.
What does this mean for solving the riddle of consciousness? It opens up new possibilities. For example, perhaps reality is some kind of huge machine that triggers our conscious experience. I have doubts about this, it still needs to be investigated. Perhaps reality is some kind of huge interactive network of mediators of consciousness, simple and complex, which evoke conscious experience of each other. In fact, this is not such a crazy idea as it seems at first glance, and now I am studying it.
But here's the thing - as soon as we let go of our intuition, a false assumption about the nature of reality arises, which opens up new ways for us to think about the greatest riddle. I bet reality will end up being something more exciting than we might imagine.
The theory of evolution challenges us: try to admit that perception is not about seeing the truth, it's about having children. And by the way, even TED only exists in our heads.
Thank you so much.
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Chris Anderson: If it's real that you are here, then thank you. So much has been said. What I mean first and foremost is that some people have probably become depressed with the mere thought that evolution does not contribute to the development of a sense of reality. Doesn't this in some way undermine all our endeavors, our ability to think that we can think with certainty, and perhaps even your own theories?
Donald Hoffman: Well, that won't stop us from doing science. We have only one false theory, which is that what we perceive is real, and in turn, that reality is what we perceive. This theory turned out to be false. OK, let's ditch this theory. But that will not stop us from coming up with new theories about the nature of reality, and this is real progress that we have realized that this theory is false. Thus, science goes further. Nothing.
CA: So you think it's possible. (Laughter) It's cool, but what you are saying may be this evolution, but it's debatable.
DH: Yes. This is a great idea. The evolutionary tests I have shown you about perception show us that our perceptions were shaped so as not to show us reality as it is, but that doesn't mean it has anything to do with logic or mathematics. We haven't done any such experiments, but I bet we find out that there is some selection pressure on our logic and mathematics, at least in the direction of truth. I mean, what if math and logic are not easy for you, like me. We are not saying this is correct, but at least the selection pressure is uniformly far removed from true mathematics and logic. Thus, I think we will understand that we will have to look at each cognitive ability and see what evolution will do to it. It is true that perception may not apply to mathematics and logic.
CA: I suppose you are offering a kind of modern interpretation of Bishop Berkeley's world: consciousness raises a question, not the other way around.
DH: Well, she's a little different from Berkeley. Berkeley considered himself a deist, and believed that the basis of the nature of reality is God, and so on, and I do not need to go the same way as Berkeley. So it's all a little different from Berkeley. I call this conscious realism. This is really a different approach.
CA: Don, I can talk to you for hours, and I hope I can do it someday.