Re: cracks and pots

["Robert J. MacG. Dawson" <rdawson@cs.stmarys.ca>]

Marta Bunge wrote;


	This [inviting researchers in fashionable applied areas to speak at
	category theory meetings] may lead to narrow
> developments of any subject that they approach with this objective in
> mind, and that is dangerous for the future of category theory (of
> mathematics, in general). That is my main concern. My posting tried to
> call attention to what I think is a sad state of affairs in category
> theory, when it need not be.

	It is not clear to me that the majority of theoretical physicists agree
with the negative view of categorical string theory held by the cited
blog writers; and in the absence of a consensus among the physicists, I
for one (with an undergradate degree and some graduate courses in
physics) do not feel qualified to take sides; if anything, errors should
be on the side of trying out too many ideas, not too few.

	I have this image of differential geometers saying to each other, a
century ago, "Don't you think somebody ought to tell that Einstein to
stop trying to use differential geometry to explain gravity, before our
whole field gets a bad name?"

	Of course, the pioneering knot theorists probably thought that Lord
Kelvin ought to stop trying to explain atomic nuclei as knotted loops of
ether, too.  But I think Einstein did differential geometry more good
than Kelvin did harm to knot theory.  A mathematical technique  powerful
enough to show that a physical theory does *not* work has shown its own
value.

	What has sometimes gone on, at least for a while, is that very abstract
physical theories have continued to be studied after it had become
obvious that their predictions were wildly at variance with observation,
or that they would never make any predictions. Even then I don't think
the reputation of the mathematical theory being abused suffers, though
that of the neighboring theoretical physicists may. I don't think this
is the case with string theory yet, though I could be wrong.

	Cheers,
	      Robert Dawson