I sent the following paragraph to Dave Fraber's IP list in response to a discussion of the universe as simulation. Back in the sixties someone (it may have been Minsky but it may equally well have been Silver, or McCarthy, or one of the other members of that circle) told me the notion that the universe might be a simulation of Newtonian mechanics on a fixed-wordlength machine, with relativity as the overflow errors and quantum mechanics as the underflow errors. If you took this seriously, you might be able to construct experiments that would give you insight into the wordlength and instruction set of the machine. Bob Taylor said that it was probably Fredkin but I think he was confusing it with Fredkin's pre-mature Wolframism. Does anyone remember who thought this up? Does anyone know Fredkin's email address? Whit