Logician Bruno Marchal ended an email like this Sep 2002
"PS I have found a way to explain with knot theory what "logic" is,
as a branch of math, by comparing propositions with knots, proofs with
continuous deformation, and semantics with knot's invariants. As I said
before one of the difficulty for writing a paper is the misunderstanding
between logicians and physicist ..."
I recalled that when I read the following in the article
"Dancing the quantum dream" from New Scientist 24th of January 2004:
"performing measurements on a braided system of quantum particles can be equivalent to performing the computation that a particular knot encodes."
Then I came to the part where the article says:
"Freedman and Kitaev (who is now also at Microsoft Research), together with Michael Larson and Zhenghan Wang, both at Indiana University in Bloomington, have now shown how to build a "topological quantum computer" using technology that is available today (www.arxiv.org/quant-ph/0101025). It seems to be the one machine that could get useful quantum computers off the drawing board."
And now I wonder: Is this the beginning of math as an empirical science?