As we go about our daily lives, we tend to assume that our perceptions — sights, sounds, textures, tastes — are an accurate portrayal of the real world...If they were not, wouldn’t evolution have weeded us out by now?...This hunch is wrong. On the contrary, our perceptions of snakes and apples, and even of space and time, do not reveal objective reality...It is a theorem of evolution by natural selection that wallops our hunches.
Does natural selection really favor seeing reality as it is? Fortunately, we don't have to wave our hands and guess; evolution is a mathematically precise theory. We can use the equations of evolution to check this out. We can have various organisms in artificial worlds compete and see which survive and which thrive, which sensory systems are more fit. A key notion in those equations is fitness...Fitness is not the same thing as reality as it is, and it's fitness, and not reality as it is, that figures centrally in the equations of evolution... we have run hundreds of thousands of evolutionary game simulations with lots of different randomly chosen worlds and organisms that compete for resources in those worlds. Some of the organisms see all of the reality, others see just part of the reality, and some see none of the reality, only fitness. Who wins? ...perception of reality goes extinct. In almost every simulation, organisms that see none of reality but are just tuned to fitness drive to extinction all the organisms that perceive reality as it is. So the bottom line is, evolution does not favor veridical, or accurate perceptions. Those perceptions of reality go extinct. Fitness beats truth (This is the "FBT theorem").
A metaphor can help our intuitions. Suppose you’re writing an email, and the icon for its file is blue, rectangular, and in the center of your desktop. Does this mean that the file itself is blue, rectangular, and in the center of your computer? Of course not...The purpose of a desktop interface is not to show you the “truth” of the computer—where “truth," in this metaphor, refers to circuits, voltages, and layers of software. Rather, the purpose of an interface is to hide the “truth” and to show simple graphics that help you perform useful tasks such as crafting emails and editing photos. If you had to toggle voltages to craft an email, your friends would never hear from you. That is what evolution has done. It has endowed us with senses that hide the truth and display the simple icons we need to survive long enough to raise offspring... Perception is not a window on objective reality. It is an interface that hides objective reality behind a veil of helpful icons...Evolution has shaped our senses to keep us alive. We have to take them seriously: if you see a speeding Maserati, don’t leap in front of it; if you see a moldy apple, don’t eat it. But it is a mistake of logic to assume that if we must take our senses seriously then we are required—or even entitled—to take them literally.
We used to think that the Earth is flat because it looks that way. Then we thought that the Earth is the unmoving center of reality because it looks that way. We were wrong. We had misinterpreted our perceptions. Now we believe that spacetime and objects are the nature of reality as it is. The theory of evolution is telling us that once again, we're wrong. We're misinterpreting the content of our perceptual experiences. There's something that exists when you don't look, but it's not spacetime and physical objects. It's...hard for us to let go of spacetime and objects...we're blind to our own blindnesses...By peering through the lens of a telescope we discovered that the Earth is not the unmoving center of reality, and by peering through the lens of the theory of evolution we discovered that spacetime and objects are not the nature of reality. When I have a perceptual experience that I describe as a red tomato, I am interacting with reality, but that reality is not a red tomato and is nothing like a red tomato...And here's the kicker: When I have a perceptual experience that I describe as a brain, or neurons, I am interacting with reality, but that reality is not a brain or neurons and is nothing like a brain or neurons. And that reality, whatever it is, is the real source of cause and effect in the world -- not brains, not neurons. Brains and neurons have no causal powers. They cause none of our perceptual experiences, and none of our behavior. Brains and neurons are a species-specific set of symbols, a hack.