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Astrophysical constraints on the simulation hypothesis for this Universe: why it is (nearly) impossible that we live in a simulation
arxiv.orgWe assess how physically realistic the ''simulation hypothesis'' for this Universe is, based on physical constraints arising from the link between information and energy, and on known astrophysical constraints. We investigate three cases: the simulation of the entire visible Universe, the simulation of Earth only, or a low resolution simulation of Earth, compatible with high-energy neutrino observations. In all cases, the amounts of energy or power required by any version of the simulation hypothesis are entirely incompatible with physics, or (literally) astronomically large, even in the lowest resolution case. Only universes with very different physical properties can produce some version of this Universe as a simulation. On the other hand, our results show that it is just impossible that this Universe is simulated by a universe sharing the same properties, regardless of technological advancements of the far future.
This really seems to miss the point of the simulation hypothesis. The simulators wouldn’t need to simulate every atom on the planet. They argue that the whole planet would need to be simulated at a certain resolution in order to be compatible with the body of existing subatomic experiments that have been done.
But this misses the point and the true abilities of the simulators of a virtual world. The whole world could be simulated at the macroscopic level, only what is needed for human perception. Then, any time some experiment probed the microscopic or subatomic world, a local fine grid simulation could be spun up in that local area to simulate what results that world would look like. Bacteria don’t actively exist everywhere - just the effects they generate on humans, plants, and animals. But if you take some pond water and look at it under a microscope, the minigame for visual microscopy is pulled up, revealing various microscopic organisms.
And the system doesn’t even need to be perfect. Has the simulation-scaling code screwed up, and the simulated humans received erroneous results, proving they live in a simulation? No problem. Just pause the simulation, adjust the code to prevent the error, and restore the simulation to an older backup.
This paper was written by physicists. So, understandably, they look at it through a physics lens. But really they should be looking at it more from a computer game designer’s perspective.
It seems to be that it depends entirely on the intent of the simulation: an experiment to find out what happens after setting the clockwork in motion, or a carefully stage-managed zoo. I say that because the partial simulation would require complete understanding of and integration with consciousness a priori, intent to mess around with conscious minds, and the Great Makers giving a shit whether we knew it was a simulation or not. That is, some sort of cosmic fishbowl for minds.
If you give up the idea of minds themselves being digital, then one interesting possibility is that the world is a training simulation/form of education.
Imagine a far future where humanity has solved most all its problems. A post-scarcity utopia where abundance is the default, no one wants for anything material, and even aging has been cured. Sounds like a great place, right? But utopia has a problem. How do you raise children in an environment where they never need want for anything? How do you raise a child to not be a narcissistic monster when they have access to what amounts to a replicator and an army of servant droids? How do you effectively raise children in a society of immortals, where only a very small number of children are born each year as very few births are required to maintain the population?
One possibility is that you don’t even try to raise children in paradise. Instead, you stick them in a simulation. Just raise them in an era before utopia came about. A simulation based on the 21st century wouldn’t be a bad choice. Early enough in history that people still have material struggles. But late enough that people are experienced with the idea of technological progress. Most ancient societies thought that technology declined with time, rather than advancing. And raising someone through a grinding virtual life as a Medieval peasant or Roman slave is probably far more hardship than the simulators have in mind. The 21st century isn’t a bad choice for a time to set a training simulation. Plus, there’s the whole overarching themes of environmental stewardship and the potential consequences therein.
That would be a pretty strong motivation to create simulations. A society of godlike immortals may simply not be capable of raising sane children. So you don’t even try. You just raise the next generation, few as they may be at any one time, in a virtual recreation of a historical era.
Maybe when you die in this world, you just wake up in the real world. Your education is complete when you’ve demonstrated some level of moral responsibility, to whatever standards the simulators value. Spent your life as a ruthless greedy billionaire? Back in the tank, you’re taking another few simulated lifetimes to work that mess out of you.
But if the macroscopic world is a consequence of the microscopic behaviour, how would you know how to simulate the macroscopic without simulating the microscopic?
With the microscopic being unsimulated, would there not be macroscopic effects without any causes? Wouldn’t be be able to detect this discrepancy on further investigation?
If you had to retroactively simulate a cause for all effects that get investigated, wouldn’t it be simpler to just simulate the microscopic in the first place?
That does assume that the universe would be simulated for our benefit and that intelligent life is not just a side effect. If that was the case then why even bother including hundreds of billions of galaxies worth of stars in the simulation.
The simulation wouldn’t actually include all those billions of stars and galaxies. In this kind of simulation, it’s all just a skybox. If you point a telescope at a distant star, then the simulation spins up a sub-simulation to produce what output a real star would experience in that situation. You include the stars and galaxies because the real universe contains them, and you want your simulation to be realistic.
It actually does make sense that the simulation would be created for us. Compare the level of computing power required to create a limited human-centric simulation to trying to simulate an entire universe. The whole-universe simulation would be some absurd power of ten times more difficult to simulate. If it is possible to simulate a world convincingly, then it’s reasonable to assume that there are many, many more low-res human-scale simulations than giant full universe simulations.
With the whole universe simulation, you also have the problem of scale. It’s hard to imagine that an entire universe can be simulated at the atomic level with anything less complex than the universe itself. Unless you have a universe-sized computer, you probably aren’t simulating an entire universe with atomic accuracy. A human-scale simulation could be performed in a universe no more complex or different from the one we observe. An atomic-scale universe-spanning simulation would have to be run from a higher level that has completely different physical laws than the one we inhabit. Occams’ razor applies. If you want to assume a simulation, it makes sense to assume a type that requires the least exotic higher-order “real” universe possible.