A simulation is a representation of something else, as a model of the Empire State building is, and an information simulation is a representation based on information. For example, a computer simulation of the weather lets us predict it, and flight simulators let pilots experience a plane without actually flying it. A simulation then represents what is real, but isn’t itself real.
The simulation hypothesis is that our world is a simulation created by computers in another physical world, as portrayed in the film The Matrix, where Morpheus says:
“What is real? How do you define ‘real’? If you’re talking about what you can feel, what you can smell, what you can taste and see, then ‘real’ is simply electrical signals interpreted by your brain.”
The hero Neo then discovers that his reality is actually a simulation of New York in 1999, fed into his brain as electrical signals by future machines in the real world, who are using humans as energy sources. Physical machines are then simulating physical events, but is that possible?
The classical processing needed to simulate a system increases exponentially with the number of particles in it because they interact, so classical computers can only calculate the behavior of a few entities (Eck, 2017), and to simulate even a couple hundred electrons would take more atoms than exist in the universe (Kendra, 2017), let alone simulating New York city or the universe. Other research finds that these calculations aren’t just implausible but logically impossible (Faizal et al., 2025), so physicists conclude that we can’t be living in a computer simulation.
Undeterred, simulation theory supporters suggest that our simulation has holes in it, so that doesn’t matter. For example, why simulate the 14 billion years of history before humans arrived, or galaxies and stars we can’t travel to, or quantum events we can’t observe? Instead of simulating a far-off galaxy, just show a dot of light so it appears real, just as movie do. Simulation theory then expects to find flaws in our reality because it is fake.
The big computer of simulation theory (Campbell, 2003) can’t calculate quantum events, so quantum theory must be flawed (Campbell, Owhadi, Sauvageau, & Watkinson, 2017), but its critics have failed to falsify it for over a century now so this is unlikely to succeed. And even if it did, finding a flaw in quantum theory would probably result in its revision rather than rejection.
If simulation theory is impossible, then machines, aliens, or our future-selves can’t create one physical world from another, but this isn’t the only version of virtualism. Annex 1 summarizes how a virtual reality can be generated by something else, and concludes that our world as a virtual reality can’t have a physical base. This excludes not only physical virtualism (the Matrix option), but also information virtualism based on hardware, and even the mind virtualism suggested by Kastrup (Kastrup, 2019). It follows that our virtual reality isn’t simulating anything physical because nothing physical can generate it.
The remaining option is quantum virtualism, that quantum events generate physical events, as proposed here. Unlike classical processing, quantum processing increases exponentially as it grows, so as space expands, it scales to match the demand, which allows a quantum network the size of our universe to generate it. Processing costs aren’t an issue, as the network of space is always active, so every moment of the past fourteen billion years happened, every far-away galaxy in our telescopes exists, and quantum events actually happen. However hard we look, in the past, far away, or microscopically, physics has found no cracks or rifts in the world we see.
Quantum reality can generate physical events because it isn’t itself physical, so it isn’t simulating itself or anything else. Our universe is on a scale we can’t imagine, so maybe we don’t know what is going on, any more than all the animals that lived and died in biological history knew that they were part of an evolution. But if we live in an evolving virtual reality, what is evolution?