Re: Poll: Are PCs Turing Machines?

From: Stephen Harris (cyberguard1048-usenet_at_yahoo.com)
Date: 12/08/04 

Date: Wed, 08 Dec 2004 21:48:53 GMT

<luiroto@yahoo.com> wrote in message
news:1102540245.045967.12450@z14g2000cwz.googlegroups.com...
>
> Will Twentyman wrote:
>> Eray Ozkural exa wrote:
>>
>> > examachine@gmail.com (Eray Ozkural exa) wrote in message
> news:<320e992a.0412011208.2b75bc@posting.google.com>...
>>> The issue is simple: a PC cannot handle *all* the data a TM can
> process.
>> Will Twentyman
>
> The issue is more simple: Turing Machines does'nt exists, only
> Turing's algorithms.
> Same: Eratosthenes Machines does'nt exists, only Eratosthenes Sieves.
> Tell me, which actual TM process has been realized that a computer
> could not manage?
>

"realized" means physically manifested. So the answer is none of course.

PCs are physical and "realized". Not taking into account time, a PC
could compute max 10^2300 digits of Pi.

TMs are not physical and could compute 10^2300000000000 digits
of Pi and then more than that.

That is quite a difference because a TM is a theoretical device
and a PC is a physical device. This is the point to the question:

Re: Poll: Are PCs Turing Machines?

The answer is NO.

Because the computation of a TM is a theoretical potential which
can never be "realized" by a physical PC. TMs never realize
any potential because there is no such thing as the turing tape
in physical reality. A PC can simulate a TM on calculations that
don't exceed the physical memory capacity of the PC.

That does not make them the same thing because they do not
have the same potential. You can make a physical like TM except
it does not have the turing described tape. So this physical like TM has
physical memory like a PC. It does not have the crucial component
that motivates the whole distinction between TMs and PCs:
A non-physical wonder tape that magically surpasses physical limitations.
Turing imagined this tape. It has never been "realized". TMs don't
do physically realized computations. None at all. PCs do, and that
is why PCs are not Turing machines.

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