Science does not have answers to all questions. There are many things that science may never be able to prove or disprove. For example, the existence of God. However, there is a topic that is much more interesting to discuss in the current scientific and near-scientific realities. It was proposed by the Swedish contemporary philosopher Nick Bostrom, as well as by several other very prominent scientists. It sounds like this: are we living in a computer simulation?
It should be admitted that even the desire to speculate on this topic can almost infuriate at least one person - Sabrina Hossenfelder. And no, this person is not a religious person. He is a theoretical physicist and popularizer of science from the Frankfurt Institute for Advanced Research (Germany). This week she decided to share her opinion on this topic on the pages of her personal blog Backreactions. However, it is worth pointing out that it is not the very statement about "our life in a computer simulation" that upsets her. She is frustrated by the fact that some prominent scientists and philosophers are making statements that, if they are facts, should certainly be reflected in our physical laws. But they are not displayed.
“I’m not saying it’s impossible,” explains Hossenfelder. "But I want to hear not only the words, but also see what can support them."
Confirming this opinion will require tremendous work and countless amount of time for mathematical calculations. In general, you will have to spend so much effort that it will be enough to solve most of the most difficult problems and gaps in theoretical physics.
So, you want to prove that the universe is in fact a simulation created by some "programmer". No, you are not approaching the issue from a religious point of view and do not say that God created the universe. You simply believe that some "omnipotent higher power" designed the universe according to their vision, and by saying this, you do not mean God at all.
To begin with, to make it more understandable to people who have just joined us and do not at all understand what is at all about, the term "computer simulation of the Universe" means that we live in the Universe, where all available space and time are based on discrete data bits. That is, somewhere there must be some ultramegasupercomputer with "ones" and "zeros", creating everything that surrounds us. But in this case, absolutely everything that is in the Universe, even on the smallest scales, must have its own certain properties, certain states or values - "yes" or "no", "1" or "0". However, according to Hossenfelder, science already knows that this cannot be.
Take quantum mechanics. There are some things in it that can really be distinguished by certain meanings, but the basis, the very basis of quantum mechanics, is not contained in the properties of objects. The basis of quantum mechanics is probabilities. Elementary particles, such as electrons, have a property called spin (angular momentum). Quantum mechanics says that if we do not observe the particles, then we cannot say with accuracy what value their spin has at this moment. We can only guess. This is the principle behind the parable of Schrödinger's cat. If a process, like radioactive decay, for example, can be determined by quantum mechanics and be responsible for whether a cat locked in a box is alive or not, then in this case, according to our current understanding of classical physics,the cat must actually be in two states at the same time - alive and dead - until we open the box to look. Quantum mechanics and classical computer bits are based on different, unrelated things.
If you dig deeper, it turns out that a certain "programmer" will have to encode many classical bits, whose values are fixed, into quantum bits governed by the uncertainty principle. Quantum bits, in turn, do not have definite meanings - not represented by zeros and ones - but instead tell us about the likelihood of taking on any of these values (including the so-called superposition state). Physicist Xiao-Gang Wen from the Perimeter Institute for Theoretical Physics tried to model all of this and present the universe as something consisting of "qubits". Hossenfelder says that Wen's models did not seem to conflict for the most part with our standard models of physics and mathematics describing the properties of our particles, but they still failed to correctly predict relativity.
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“But he didn’t claim that we are living in a computer simulation. He just tried to explain the likelihood that the universe could be composed of qubits,”commented Hossenfelder.
Any evidence that we are living in a simulation will require us to revise all our laws of particle physics (general and special relativity) and use a different interpretation of quantum mechanics, on the basis of which its current laws are derived, so that it can perfectly describe our universe. … What is most interesting, there are people who devote their whole lives to this, but at the same time they do not come an inch closer to their cherished goal.
Scott Aaronson, an expert in the field of the theory of computers and systems, talks about the likelihood of the existence of theories that can combine gravity with quantum mechanics. And if our Universe really consists of quantum bits, then sooner or later someone will be able to deduce and correctly substantiate these theories. Therefore, if there are those among people who would like to solve one of the most difficult riddles in theoretical physics, then you are welcome. Aaronson himself refers himself rather to the "camp of uninterested" in deciding whether our Universe is virtual or not, but nevertheless, he also has his own opinion on the issue:
“Why not take and simplify this hypothesis by excluding the“aliens”or whoever is in charge from the equation, if the presence of this factor has no practical benefit in solving the hypothesis?” - asks Aaronson.
Definitely, be it "aliens" or some "main programmer" - all of them would in this case be the highest "forms of life", which we most likely would never have been destined to understand. And if our theories work without the assumption that we can all live in a simulation, then why bother trying to find an explanation for what we essentially don't need?
And yet, as a computer scientist, Aaronson could not ask another equally interesting question: is it possible, according to our rules of computer computing, to create a simulation, on a scale of the Universe? In the case of modeling our Universe, according to Aaronson, according to the roughest and most optimistic assumptions, 10 ^ 122 qubits would be needed. (This number would represent one with 122 zeros, while some estimates put the approximate number of atoms in our universe at 10 ^ 80). No less interesting would be the question of whether this hypothetically created virtual Universe is capable of bypassing the stopping problem and calculating its end in advance, that is, to do what ordinary computer programs are not capable of.
After all, those who believe in a "simulation model of the universe" can simply change the parameters in the simulation to ultimately validate their assumptions. But this will no longer be science. It will be a religion, with aliens or some "main programmer" instead of God. Yet neither Hossenfelder nor Aaronson claim that all of us can or cannot live in simulation. They only say that if you can prove it, then you will need much more effort than just shaking your hands and having philosophical conversations. You need irrefutable proof that the architecture of the Universe works like one giant computer and does not contradict the most complex laws of our physics.
“I don’t convince anyone and I don’t force anyone to give up trying to prove it. Quite the opposite. I urge you to prove it,”concludes Hossenfelder.
"What annoys me most about all this is the attempt to abandon all the fundamental theories and laws that we already have on our hands."
NIKOLAY KHIZHNYAK
