When we could keep track of five sets of numbers all at once, we did the really extreme stuff: waking-state lucid dreaming and elective multiple identity architecture: IEDs for the mind. We lived symbols, puzzles, philosophical loops and psychological paradoxes. We learned that to lie to a machine, you don’t need to be a perfect liar: rather, you need only believe that everything is a lie. If the world is not real, if everything we see is a simulation or a game, then the fictions we append to it are no different from the ones which come to us through our senses. And it is true: the odds, overwhelmingly, tell us that we exist inside a computer. Any universe that can support technological life probably will, given enough time. Any technological civilisation will develop modelling, and will in a comparatively insignificant span be able to model everything a planet-bound species could expect to encounter. That being the case, the simulation will rapidly reach the point where it contains simulated computers with the ability to simulate likewise everything a planet-bound species could expect to encounter, and so on and so on in an infinite regress limited only by computing power.