2012/9/11 Quentin Anciaux <[email protected]> > > > 2012/9/11 benjayk <[email protected]> > >> >> >> Quentin Anciaux-2 wrote: >> > >> > 2012/9/11 benjayk <[email protected]> >> > >> >> >> >> >> >> Quentin Anciaux-2 wrote: >> >> > >> >> > 2012/9/11 benjayk <[email protected]> >> >> > >> >> >> >> >> >> >> >> >> Quentin Anciaux-2 wrote: >> >> >> > >> >> >> > 2012/9/10 benjayk <[email protected]> >> >> >> > >> >> >> >> >> >> >> >> >> >> >> >> > > 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*). >> > > What's your point ? How the simulated hardware would fail ? It's > impossible, so until you're clearer (your point is totally fuzzy), I stick > to "you must be wrong". >
So either you assume some kind of "oracle" device, in this case, the thing you describe is no more a program, but a program + an oracle, the oracle obviously is not simulable on a turing machine, or an infinite regress of level. Halting problem is not new, I still don't see your point or something new here. Quentin > >> 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 [email protected]. >> To unsubscribe from this group, send email to >> [email protected]. >> For more options, visit this group at >> http://groups.google.com/group/everything-list?hl=en. >> >> > > > -- > All those moments will be lost in time, like tears in rain. > -- All those moments will be lost in time, like tears in rain. -- You received this message because you are subscribed to the Google Groups "Everything List" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/everything-list?hl=en.
