> hypothesize that only computable and decidable (in Godel's sense) structures exist The arithmetic hierarchy is a study of non-computable/decidable sets. htt

> hypothesize that only computable and decidable (in Godel's sense) structures exist The arithmetic hierarchy is a study of non-computable/decidable sets. https://en.wikipedia.org/wiki/Arithmetical_hierarchy https://en.wikipedia.org/wiki/Arithmetical_hierarchy > Or, more accurately, Gödel forbids the existence (in both logical and Tegmarkian senses) mathematical structures that are (a) powerful enough, (b) complete, and (c) self-consistent. But Tegmark here seems to make a much stronger claim, namely that, in his ontology, structures that are (a) do not exist and thus everything ontologically real is both (b) and (c) – finite in the sense that neither undecidable nor semidecidable problems exist. Ys, but is different from claiming that "only computable and decidable exist"