From mboxrd@z Thu Jan 1 00:00:00 1970 X-Msuck: nntp://news.gmane.io/gmane.science.mathematics.categories/3096 Path: news.gmane.org!not-for-mail From: "Robert J. MacG. Dawson" Newsgroups: gmane.science.mathematics.categories Subject: Re: cracks and pots Date: Tue, 14 Mar 2006 12:05:43 -0400 Message-ID: <4416E9D7.4030704@cs.stmarys.ca> References: NNTP-Posting-Host: main.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Trace: ger.gmane.org 1241019092 7224 80.91.229.2 (29 Apr 2009 15:31:32 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Wed, 29 Apr 2009 15:31:32 +0000 (UTC) To: categories@mta.ca Original-X-From: rrosebru@mta.ca Tue Mar 14 18:53:00 2006 -0400 Return-path: Envelope-to: categories-list@mta.ca Delivery-date: Tue, 14 Mar 2006 18:53:00 -0400 Original-Received: from Majordom by mailserv.mta.ca with local (Exim 4.52) id 1FJIMQ-00031K-GC for categories-list@mta.ca; Tue, 14 Mar 2006 18:51:26 -0400 User-Agent: Mozilla Thunderbird 1.0.2 (Windows/20050317) X-Accept-Language: en-us, en In-Reply-To: X-Spam-Checker-Version: SpamAssassin 3.0.4 (2005-06-05) on mx1.mta.ca X-Spam-Level: X-Spam-Status: No, score=0.1 required=5.0 tests=FORGED_RCVD_HELO autolearn=disabled version=3.0.4 Original-Sender: cat-dist@mta.ca Precedence: bulk X-Keywords: X-UID: 42 Original-Lines: 59 Xref: news.gmane.org gmane.science.mathematics.categories:3096 Archived-At: Marta Bunge wrote: > Hi, > > I just came across the following pages > > http://motls.blogspot.com/2004/11/category-theory-and-physics.html > http://motls.blogspot.com/2004/11/this-week-208-analysis.html > > written by Lubos Motl, a physicist (string theorist). Some of you may find > these articles interesting and probably revealing. > > Are we category theorists as a whole going to quietly accept getting > discredited by a minority of us presumably applying category theory to > string theory? It is surely not too late to react and point out that > this is not what (all of) category theory is about. I don't see that we have any more need to do this than (for instance) algebraic topologist, group theorists, or differential geometers have when somebody floats a perhaps-too-conjectural theory using those branches of mathematics. Heck, physicists have managed to come up with what are now generally seen as dubious theories using nothing more than elementary arithmetic (Dirac's Big Numbers hypothesis, say.) Do the number theorists have to protest this? Big problems in physics have tended to be solved only after a lot of attempts that look pretty strange in retrospect (think of some of the early models of the atom!) But correct theories (or at least theories that represent a major improvement in understanding and prediction) can also look pretty strange; think how general relativity, or even special relativity, must have looked in their day. I seem to recall that the periodic table was originally considered at least as dubious as Bode's Law - and if they had been able to measure molecular masses more accurately in Mendeleev's day, they would have seen that the main idea was actually _wrong_, and its acceptance would probably have had to await the technology to separate individual isotopes, which do have (reasonably) predictable masses. Quaternions were fashionable in Victorian days to represent motions in space, dropped out of fashion when people decided that the restriction of their applicability to three-dimensional space was parochial, and dropped back in again when people realized that in fact a three-plus-one-dimensional spacetime had some rather special properties. Mathematics, like the phone service, is a "common carrier". We develop it; we use it; but we have neither the right nor the obligation to police how others apply it (unless they get the mathematics itself wrong?). Moreover, given the historical difficulty of recognizing good physical theories ahead of time, it would be impossible to do so wisely even if we had the right. I do not see how anybody can possibly discredit category theory by applying it to string theory, even inappropriately, any more than "The da Vinci Code" discredits classical geometry and number theory. -Robert Dawson