I often asked myself this question. I realized that all well known phenomenons in nature behave according to some very mathematical laws. Since I study computer science I had the chance to get a look into the mathematical world. I also realized that mathematics is strongly coupled with computer science because in computers we could define some laws that it has to follow and afterward it does exactly what we said. So you could transform an equation into a program and vice versa. So theoretically when we would have a perfect mathematical and complete description of the world we could possibly simulate some parts of it. (Nearly all the computer simulation done today are very coarse and not complete. They mostly simplify the problem such that it runs efficiently on a computer.)
But for me is clear that a program and the physics of the real world are coupled. At least you can’t say wich world can describe more information. Both can “simulate” the other. Something you might think is, that a simulation without real physics is not possible. This is true but it is possible to have a physics only inside a simulation independent of the real physics. And inside this physics you can say there is no physic without the computer. Ok enough from that. Why should we be a simulation? As I said everything well-known behaves very mathematically like a computer program. Another argument is that we don’t know any infinite thing. Maybe the universe is infinite but maybe not. We don’t know. So in a computer program there is also nothing infinite. There are cycles but nothing infinite that doesn’t repeat itself. If we assume that the simulation we run on is made on a computer similar to ours, than there is a smallest length of space and time. This length can not be divided further. This length is proposed be Max Planck (Planck Length) but it is way too small to detect it with our instruments today. Let’s assume there is the Planck Length wich can not be divided. This is similar to a number on a computer. Say you have 3 decimal places. So 0.01 is the smallest unit. There is no 0.005 in this computers world. (finite precision floating point) If our world is simulated on a computer working with finite memory than if we fly out from the earth to the border of the universe we either come to the same place again (overflow of the variable that defines the position), we get stuck in some state (state that decodes that the position coordinates are too big to store) or we crash the simulation (we use all the memory for our positional coordinates). Sadly there is no way to compute the distance to go until one of this effects need to occur, we would have to know the size of the memory and how our world is represented. On the other hand if we get one of these effects we could infer pretty straight forward how our world is implemented. Maybe some think that the aliens simulating us don’t use a computer like we have. That is possible I only describe what observable phenomenons could be if they do. But let’s be clear if they use a computer with finite precision and finite memory than such effects have to occur. And also the fact that we haven’t found any infinite thing suggests that the the simulation we run in has also no infinite structure.
Some people say they are surely not a simulation because they are conscious. Consciousness is the last stand for many of the more esoteric or religious questions even though, few religions are talking about it. But this topic is for another blog.
But what is the answer? I think it is obvious that this question is not easily answered and I only wanted to give some arguments. (The title was only to bait 😉 )