2015-10-13 14:26 GMT+02:00 Bruce Kellett <bhkell...@optusnet.com.au>:
> On 13/10/2015 11:00 pm, Quentin Anciaux wrote: > > 2015-10-13 13:44 GMT+02:00 Bruce Kellett <bhkell...@optusnet.com.au>: > >> A computer made of silicon can emulate a Turing machine. A brain made of >> wetware can be emulated by a silicon computer, or a Turing machine. The >> fact that a Turing machine can be define mathematically is entirely >> secondary. >> > > The fact that a computer made of matter can emulate a Turing machine is > because we have a definition of a turing machine which is a mathematical > concept... but if you reject the mathematical definition, I wonder how you > can say that a "computer" emulate a turing machine... You should first > define computation in terms of matter, and shows that the "mathematical" > game is coincidentally like it. > > > Who said I reject the mathematical definition of a Turing machine? > If you don't reject it, your explanation of computation is circular if you don't have a *definition* of what is a physical computation without using the mathematical definition. > A computer emulates a Turing machine in the sense that the silicon based > computer can do everything that an ideal Turing machine can do -- in fact, > the modern computer on your desk is a perfect universal Turing machine. I > don't have to *define* computation in terms of matter -- > You do have to, for not to be circular. > I simply have to compute the output from the given input. > > Also I wonder how you could justify with such theory the equivalence > between two computations... if not by using abstract computation theory to > justify it... > > Two computations are equivalent if they give the same answers. > > How do you justify it ? I can easily write an emulator of another machine > and justify the correct functionning by logic alone, no matter involve... > so if logic is just a game, and matter is the end point, algorithm *can't* > be used as justification of the correct working. > > > Who said matter was the end point? > > You... why do you insist on matter, if it is not primary and can be made > of something else ? > > > Who said matter was not primary? > Who said it was ? If it is not, then reality can be explained in terms of computations alone, and matter could be a product of computations... You dislike that idea, that somehow must mean matter is primary in your view... so IMO, you're saying matter is primary, don't you ? > > > I can justify the equivalence of two computations by pointing to the fact >> that they give the same numerical output. >> > > Then you say it only if you have achieved all possible outputs ? because > you can't use mathematical induction to justify they will on the same > domain. > > > A computation has one input and one output -- it is a mapping between the > input and the output. > Yes so to prove them equivalent, you have to prove the mapping between input and output for all input... how do you achieve that without mathematical induction ? > Different inputs may give different outputs, but then they are different > calculations. > > > Computations might be definable in terms of algorithms, but more than one >> algorithm can give the same computation -- give the same result for the >> given input. >> > > Yes, an infinity of them... but that's a mathematical result... no matter > is used in the reasoning . > > > That mathematical result can be instantiated by actually doing the same > calculation -- same output for the given input -- in a number of different > ways. I can do this without recourse to any mathematics at all. The > material world can be considered as a model instantiating the mathematical > result. This does not diminish either the physical or the mathematical -- > they ride on this together. > > Bruce > > -- > You received this message because you are subscribed to the Google Groups > "Everything List" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to everything-list+unsubscr...@googlegroups.com. > To post to this group, send email to everything-list@googlegroups.com. > Visit this group at http://groups.google.com/group/everything-list. > For more options, visit https://groups.google.com/d/optout. > -- All those moments will be lost in time, like tears in rain. (Roy Batty/Rutger Hauer) -- You received this message because you are subscribed to the Google Groups "Everything List" group. To unsubscribe from this group and stop receiving emails from it, send an email to everything-list+unsubscr...@googlegroups.com. To post to this group, send email to everything-list@googlegroups.com. Visit this group at http://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/d/optout.
