From: HARNAD Stevan (harnad@coglit.ecs.soton.ac.uk)
Date: Mon May 28 2001 - 21:47:39 BST
On Mon, 28 May 2001, Basto Jorge wrote:
> Harnad, S. (2000) Minds, Machines, and Turing: The
> Indistinguishability of Indistinguishables. Journal of Logic,
> Language, and Information 9(4): 425-445. (special issue on "Alan
> Turing and Artificial Intelligence")
> http://www.cogsci.soton.ac.uk/~harnad/Papers/Harnad/harnad00.turing.html
> If there are competitive or complementary
> speculations of unified theories
> (strings, super simmetry, and so on...)
> that is because as to date there is no
> empirical data to go for any of them.
> As soon as we are able to put them under
> empirical testing, the set of
> choices will narrow; and if by the end
> there will be more then one then
> those will be part of the SINGLE unified theory.
> Or am I completely wrong?
There is no guarantee whatsoever that at the "end" when all data are
all explained, that there will be only one explanation, nor even that
competing explanations will all be integrable into one. I think you
are confusing the unification of the forces (that is to say, the
explanation of the empirical phenomena that exists) with the
unification of theories of the forces. The GUTE will explain all the
forces, in a unified way. But there is no guarantee there will be
only one GUTE that can do this!
You are right that right now there is not even one, but that is not
what we are talking about. We are talking about when there is at least
one: What if there is more than one?
Some have speculated that, if so, they will be "notational variants,"
equivalent to one another, rather like the many equivalent formulations
of computation, Turing Machine, general recursive function, or the
Heisenberg (matrix) vs. Schrodinger (wave equation) formulation of
quantum menchnics. But the latter formal equivalences have been proved.
It is not at all clear that we can count on that in the case of
GUTEs. Many theories are, after all, NOT equivalent...
Stevan Harnad
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