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

From: John K Clark (
Date: Wed Oct 14 2009 - 23:04:22 MDT

On Wed, 14 Oct 2009 "Mu In Taiwan" <> said:

> Turing proved things about Turing Machines in 1936; not computers.

He proved things about both. He used Turing Machines to prove things
that must be true for anything powerful enough to do arithmetic, like
computers, or you and me.

> 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.

That is entirely true. A computer is not a Turing Machine nor is a
human, it is an abstract tool used in formal logic. In a similar way
Carnot heat engines do not and can not exist in the real world but
engineers still study them because they tell you the limits of what a
heat engine can do; if even a Carnot engine can't do something a real
engine never could.

An engine consumes gasoline not the laws of thermodynamics, certainly it
does not understand them; and yet a mind can use those laws to determine
the limits of what ANY heat engine can do regardless of the precise
details of its construction. A mind might not be a Turing Machine, use
formal logic, or even know the first thing about it. Nevertheless we can
use that discipline to know there are some tasks a mind can never
accomplish even with infinite time; and whatís more there is no way to
know beforehand what all those tasks are. You canít know for certain if
you are in a infinite loop or not, you must use your judgment, if you
judge you probably are in such a loop then jump out.

You can't build a Turing Machine but you can use the abstraction of one
to prove that any system, computer, or mind that is powerful enough to
do arithmetic is subject to the limitations that Goedel and Turing

> I note from
> that you believe yourself to be a computer program.

Well,its not relevant to the question we've been discussing but you
brought it up. I don't think I'm a computer program although I could in
principle be one someday. I am not a noun, I am a adjective, I am the
way atoms react when it is organized in a johnkclarkian way. In short I
am information, my atoms are just generic.

> You also claim not to possess a subjective experience in that post I
> refer to above.

Oh I have subjective experiences. In fact I think my subjectivity is the
most important thing in the universe. You may disagree. I have a hunch
you have subjective experiences too, although I can't prove it. I think
it unlikely I am the only conscious being in the universe, but that's
just another hunch.

> 'you' ought not to be offended when I call 'you' an unhinged lunatic.

You know, sometimes I almost think you are being unfriendly.

 John K Clark

  John K Clark
-- - Same, same, but different...

This archive was generated by hypermail 2.1.5 : Wed Jul 17 2013 - 04:01:05 MDT