Quentin Anciaux-2 wrote: > > 2012/9/11 benjayk <benjamin.jaku...@googlemail.com> > >> >> >> Quentin Anciaux-2 wrote: >> > >> > 2012/9/11 benjayk <benjamin.jaku...@googlemail.com> >> > >> >> >> >> >> >> Quentin Anciaux-2 wrote: >> >> > >> >> > 2012/9/10 benjayk <benjamin.jaku...@googlemail.com> >> >> > >> >> >> >> >> >> >> >> >> > > No program can determine its hardware. This is a consequence >> of >> >> the >> >> >> > > Church >> >> >> > > Turing thesis. The particular machine at the lowest level has >> no >> >> >> > bearing >> >> >> > > (from the program's perspective). >> >> >> > If that is true, we can show that CT must be false, because we >> *can* >> >> >> > define >> >> >> > a "meta-program" that has access to (part of) its own hardware >> >> (which >> >> >> > still >> >> >> > is intuitively computable - we can even implement it on a >> computer). >> >> >> > >> >> >> >> >> >> It's false, the program *can't* know that the hardware it has >> access >> >> to >> >> >> is >> >> >> the *real* hardware and not a simulated hardware. The program has >> only >> >> >> access to hardware through IO, and it can't tell (as never ever) >> from >> >> >> that >> >> >> interface if what's outside is the *real* outside or simulated >> >> outside. >> >> >> <\quote> >> >> >> Yes that is true. If anything it is true because the hardware is >> not >> >> even >> >> >> clearly determined at the base level (quantum uncertainty). >> >> >> I should have expressed myself more accurately and written " >> >> "hardware" >> >> " >> >> >> or >> >> >> "relative 'hardware'". We can define a (meta-)programs that have >> >> access >> >> >> to >> >> >> their "hardware" in the sense of knowing what they are running on >> >> >> relative >> >> >> to some notion of "hardware". They cannot be emulated using >> universal >> >> >> turing >> >> >> machines >> >> > >> >> > >> >> > Then it's not a program if it can't run on a universal turing >> machine. >> >> > >> >> The funny thing is, it *can* run on a universal turing machine. Just >> that >> >> it >> >> may lose relative correctness if we do that. >> > >> > >> > Then you must be wrong... I don't understand your point. If it's a >> program >> > it has access to the "outside" through IO, hence it is impossible for a >> > program to differentiate "real" outside from simulated outside... It's >> a >> > simple fact, so either you're wrong or what you're describing is not a >> > program, not an algorithm and not a computation. >> OK, it depends on what you mean by "program". If you presume that a >> program >> can't access its "hardware", > > > I *do not presume it*... it's a *fact*. > > Well, I presented a model of a program that can do that (on some level, not on the level of physical hardware), and is a program in the most fundamental way (doing step-by-step execution of instructions). All you need is a program hierarchy where some programs have access to programs that are below them in the hierarchy (which are the "hardware" though not the *hardware*).
So apparently it is not so much a fact about programs in a common sense way, but about a narrow conception of what programs can be. benjayk -- View this message in context: http://old.nabble.com/Why-the-Church-Turing-thesis--tp34348236p34417762.html Sent from the Everything List mailing list archive at Nabble.com. -- You received this message because you are subscribed to the Google Groups "Everything List" group. To post to this group, send email to everything-list@googlegroups.com. To unsubscribe from this group, send email to everything-list+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/everything-list?hl=en.