Self-Reproducing Automata and the Impossibility of SETI

Abstract

Opponents of the Search for Extraterrestrial Intelligence (SETI) argue that it may be unfeasible to send ‘unmanned’ probes to the billions of planets in the galaxy. Their impossibility proof depends on a technology called self-reproducing automata (SRAs), as proven by the Hungarian mathematician John von Neumann. Since more advanced civilizations would surely have developed this technology long ago, the exponential growth of those machines would have placed them in every planetary system by now – yet, there is no evidence of such machines. The potential application of von Neumann’s idea to space exploration allows us to realize some crippling shortcomings of the metaphor: genomes are not like computer programs and living beings are not automata. The SRAs are unlikely to reproduce, and the impossibility proof fails.