It's the kind of argument people conjure when they think, not consciously, but subconsciously, that computers are magic. I've been there. You view the world as

It's the kind of argument people conjure when they think, not consciously, but subconsciously, that computers are magic. I've been there. You view the world as simple and slow, and computers as this complex and magical technology that is getting twice as fast every five years. You don't properly understand the limits of physics, so you extrapolate the progress of technology well past them until you believe it will be possible for a computer the size of a fist to simulate an entire planet. In a nutshell, some people believe in Moore's law more than they believe in the laws of physics: the failure of the former would surprise them more than the failure of the latter. > What is meant by computer? What is meant by a simulation? These are especially interesting questions once you think about the low hanging fruits for optimizing a world simulator. If you want to simulate the interaction between two systems as efficiently as possible, you want the states for these two systems to be located as closely together as possible, in order to minimize communication overhead. And if you are trying to simulate a 3D universe, and calculate what would minimize internal communication delays, the best computer architecture to do this is, well... it's going to be isomorphic to what you are simulating. That is to say, if you travel around the planet in the most efficient computer simulator, an external observer would probably see a bunch of photons and electrons travelling in a physical circle inside the simulator. And the ensemble of transistors that simulate you at any given moment would probably physically look like you. When your simulator physically looks like the universe it is simulating, is it still a simulation? Or is it in the middle of some spectrum between real and simulated? Ontological haze indeed.