The Simulation Argument proposed by Nick Bostrom in 2003 remains the single most perplexing answer to the Fermi Paradox yet proposed.
The short version of these two arguments are:
– Fermi Paradox: Given how many habitable planets there are in the Galaxy and how long they’ve been about… where the hell are all the aliens? They should have over run the place with von Neumann probes already!
– Simulation Argument: Given that it will become possible in the future to simulate not just individuals but whole populations, it is significantly more probable that we are ancestor simulations being run by our future prodigy rather than real world residents who will first develop that technology.
So SA’s answer to FP is simply: You are a Sim. The simulation does not include the aliens.