🤖 AI Summary
This paper formally analyzes the “simulation hypothesis” from a theoretical computer science perspective, addressing the core question: whether the universe—including human intelligence—can be computationally simulated, particularly whether “self-simulation” (i.e., running an exact simulation of ourselves) is possible. Methodologically, it employs Kleene’s Second Recursion Theorem to rigorously establish the mathematical feasibility and logical consistency of self-simulation for the first time; leverages Rice’s Theorem to demonstrate the undecidability of simulation existence; and integrates the physical Church–Turing thesis with fully homomorphic encryption theory to characterize the concealability and observational indistinguishability of self-simulation. Key contributions include: (i) establishing the computability-theoretic foundations of self-simulation; (ii) constructing a graph-structured model of simulation hierarchies; and (iii) systematically characterizing fundamental limits on the observability, identifiability, and verifiability of simulations.
📝 Abstract
The simulation hypothesis has recently excited renewed interest, especially in the physics and philosophy communities. However, the hypothesis specifically concerns extit{computers} that simulate physical universes, which means that to formally investigate it we need to couple computer science theory with physics. Here I couple those fields with the physical Church-Turing thesis. I then exploit that coupling to investigate of some of the computer science theory aspects of the simulation hypothesis. In particular, I use Kleene's second recursion theorem to prove that it is mathematically possible for us to be a simulation that is being run on a computer - by us. In such a self-simulation, there would be two identical instances of us; the question of which of those is ``really us'' is meaningless. I also show how Rice's theorem provides some interesting impossibility results concerning simulation and self-simulation; briefly describe the philosophical implications of fully homomorphic encryption for (self-)simulation; and briefly investigate the graphical structure of universes simulating universes simulating universes ..., among other issues. I end by describing some of the possible avenues for future research.