Re: [sl4] Alan Turing's results are profound

From: Mu In Taiwan (
Date: Wed Oct 14 2009 - 15:36:27 MDT

Wow... so many replies, yet so few attempts to check the axioms and

Starting from the beginning of JC's post:

JC wrote: "I confess to being a little shocked when somebody on this list
said that
all Turing did was prove the trivial fact that a program like the one
that produced the digits of Pi will never halt. I was shocked at this
misunderstanding because I think Turing's results are some of the most
important in all of science."
Well, those are claims about your own mental state and what you believe, no
problem there.

JC: "He proved that a computer, and by simple extension a mind, can't do

A computer? By simple extension a mind?

What utter tosh! And consequently the rest of your post, based as it is
around these claims, is of no value. If your axioms or reasoning are wrong,
your conclusions are wrong and should be discarded.

1 - Turing proved things about Turing Machines in 1936; not computers.
Turing Machines are not the same as physical computers; they are
mathematical abstractions that cannot and do not exist in the real world.
This is a fact of physics. There's just no room for the tape.

2 - If you would like to prove me wrong, simply show me a turing machine - a
photo would suffice - to demonstrate that it can exist in the real world. I
will be looking out for the infinite tape, in particular. Note that regular
computers are finite state machines, because, surprise surprise, they have a
finite set of states.

3 - "by simple extension a mind"? Humans have been disagreeing about what
constitutes brain and mind for over 2000 years, and you think you can
casually explain all future minds as being Turing machines with the two
words 'simple extension'? Such arrogance!

4 - You keep being asked to provide your evidence that 'all future minds
will be turing machines'. You keep failing to do so. Why are you failing to
do so?

5 - Considering that the only known examples of minds that we have (human
minds / human brains, depending on your point of view) are clearly not
Turing machines (they lack infinite state), this would seem to be the
strongest possible evidence that you do not know what you're talking about.

6 - I note from that
you believe yourself to be a computer program. This is a quite extraordinary
delusion, and is perhaps also the source of the cognitive dissonance that
you appear to be experiencing when people on this list present you with
inconvertible facts such as, 'there's not enough room on this planet for a
turing machine' and mathematical results such as 'e.g. the halting problem
only applies to theoretical turing machines'.

7 - You also claim not to possess a subjective experience in that post I
refer to above. In that case, 'you' ought not to be offended when I call
'you' an unhinged lunatic. Sure, we might see the body of John Clark react
in anger, but no harm has actually been done - nobody subjectively
experienced the feeling of being insulted, don't you agree?

8 - In an attempt to end your continual misrepresentation of Church and
Turing's work, I refer you to a peer-reviewed research paper that describes
your mistake in depth, and why it is a mistake.

Before you dismiss this paper without reading it - as I expect you will - I
want to note that the author is the Director of the Turing Archive for the
History of Computing, and a well-known author of numerous books about Alan
Turing and Artificial Intelligence. He is widely considered to be one of the
world's top authorities on what Alan Turing said and did.

"The Broad Conception of Computation" B. JACK COPELAND, 1997

"*A myth has arisen concerning Turing's article of 1936, namely that Turing
set forth a fundamental principle concerning the limits of what can be
computed by machine—a myth that has passed into cognitive science and the
philosophy of minds to wide and pernicious effect. This supposed principle,
sometimes incorrectly termed the* Church-Turing thesis, *is the claim that the
class of functions that can be computed by machines is identical to the
class of functions that can be computed by Turing machines. In point of
fact, Turing himself nowhere endorses or even states this claim (nor does
Church). The author describes a number of notional machines, both analog and
digital, that can compute more than a universal Turing machine. These
machines are exemplars of the class of nonclassical computing machines.
Nothing known at present rules out the possibility that machines in this
class will one day be built or that the brain itself is such a machine. These
theoretical considerations undercut a number of foundational arguments that
are commonly rehearsed in cognitive science and gesture toward a new class
of cognitive models*."



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