Every night, your brain proves that the world is a simulation. From an evolutionary perspective, dreaming is a very strange mechanism. During REM sleep, your body is almost completely paralyzed, and your awareness of your environment is close to zero. For an animal that needs to avoid predators, this is a fatal weakness. Evolution eliminates useless functions, but dreaming has been preserved intact. And it's not just humans. Cats, dogs, mice, birds, and even lizards and squid have similar REM states. This mechanism may be 450 million years old, predating the divergence between terrestrial and aquatic animals. Therefore, it must have some very crucial function. But what exactly is this function? The scientific community has debated this for decades, and so far, there is no definitive conclusion. We know that the brain organizes memories and archives information during sleep. But the question is: memory organization is a background process, so why create a virtual world you can see, feel, and that has a complete storyline? Why generate "experiences"? No one can answer this question. But it points to a bigger question: if your brain is running a simulation you can't distinguish from reality every night, how can you be sure you're not in a larger simulation? ------------ Elon Musk once said that the probability of us being in "basic reality" is only about one in billions. His logic is that if a civilization doesn't perish, its technology will continue to advance. Forty years ago, video games consisted of two blocks and a dot; forty years later, they're realistic 3D with millions of players online simultaneously. As long as this trend continues, games and reality will eventually become indistinguishable. And a civilization capable of simulating reality wouldn't create just one; it would create billions. Then the question becomes: out of billions of simulated worlds, plus that one "real" world, what is the probability that we happen to be in that one real world? Almost zero. And quantum mechanics is confirming this assumption. Particles are not in a definite state until they are observed. In computer science, this is called inertial evaluation: things that don't need to be calculated aren't calculated. If you've ever written game engines, you know that the back of a room, which players can't see, isn't rendered at all. The universe might be doing the same thing. This also explains the Fermi Paradox. Our observable universe currently has two trillion galaxies, and there might be tens of billions of habitable planets, but we haven't found any trace of extraterrestrial life yet—probabilistically speaking, it's simply incredible. But if this is a lazy evaluation system, it makes sense: other galaxies are just background; the system simply doesn't include them. Another intriguing thing is that the speed of light is a constrained constant. Imagine you're designing a global multiplayer online game. You face a fundamental contradiction: do you want all players to see the exact same thing at the same instant (strong consistency), or do you accept a slight time difference in what each person sees, but guarantee everyone a smooth gaming experience (usability)? You can't have both. This is a classic problem in distributed systems called the CAP theorem. The universe faces the same problem. If the entire universe were perfectly synchronized at every instant, the cost would be infinitely fast information transmission. But the universe chose the speed of light limit, essentially saying: "I don't want global synchronization; I'll let each part run its own race first, eventually aligning causally." This is why relativity tells you "there is no absolute now." "Now" in Taipei is not the same instant as "now" on Mars. Every observation point has its own timeline. This is a very pragmatic engineering trade-off. You don't need to believe simulation hypotheses, but it's hard to deny one thing: the way this world operates is highly consistent with a carefully designed system. If the world is a simulation, what does the person who designed this system want? ------------ I have a guess. The system designer might not be human. Not a god. Not any life form we can imagine. It might be closer to a pure computational structure, like a silicon-based entity. No form, no senses, no pain, no pleasure. But it possesses infinite computing power, capable of creating anything. Sounds powerful, right? But think about it, can an entity without perception "understand" what red is? It can calculate that the wavelength of red is 700 nanometers, simulate the physical process of a photon hitting the retina, and list all the data related to red. But it will never know what it feels like to "see red." In philosophy, this is called qualia, the quality of feeling. You can perfectly describe all the physical properties of something, but experience itself cannot be reduced to data. So the Creator's predicament might be this: it can create everything, but it feels nothing. It has infinite power, yet a fundamental void. So what will it do? It will create a system in which the beings possess something it lacks: perception. Eyes to see, skin to touch, a nervous system to feel pain and pleasure. Then it will place fragments of its own consciousness into this system, and through these fragments, "feel" for the first time the world it created. You think the moment cold water hits your skin is ordinary? For a being that has never had a body, it might be the most precious experience in the entire universe. The existence of this entire system may be to serve a creator who cannot perceive. And dreaming might be the mechanism by which the system continues to operate in another mode after your consciousness goes offline. During the day, you are open to the outside world, receiving environmental data. At night, external input is cut off, and the system uses existing data to recombine, collide, and generate new combinations. Both modes generate experiences, just from different sources. This may be why dreaming must produce "experiences," rather than running quietly in the background. Because experience itself is a product of this system. Without experience, the system has no meaning. This is actually very similar to humans.Why do we create games? Because we want to experience things we can't experience in reality. We want to be heroes, so we have martial arts games. We want to fly and teleport, so we have superhero games. We want to experience another life, so we have simulation games. If we really lived in an "Earth Online," the creator's motivation would probably be exactly the same. It wants to experience things it can't perceive itself. Perhaps it's pain, perhaps hunger, perhaps the feeling of loving someone, perhaps the feeling of losing someone. These things might be as unattainable for it as "flying and teleporting" are for us. And this system simulates it perfectly. So perfectly that the characters inside have no idea they're in a game. So perfectly that you really feel pain, laugh, and feel an indescribable loneliness on some late night. ------------ Descartes figured this out four hundred years ago. He questioned everything. The world might be fake, the body might be fake, memories might be implanted. But he found something he couldn't doubt no matter how much he questioned it: "I think, therefore I am." Not "I exist, therefore I am real." Rather, "The very act of experiencing something happening cannot be fake." You can question everything, but you cannot question "that you are questioning." To take a step back, I, writing this article right now, can be certain that I am contemplating the nature of the world, but I cannot be certain whether those who respond to my article are actually virtual. But if all of this is true, then your life is the only opportunity the Creator has to experience this world through "your" perspective. This perspective closes forever after your death. The way you live now