Full Idea
The solution was to turn around the question How can one in the known mathematical scheme express a given experimental situation? and ask Is it true that only such situations can arise in nature as can be expressed in the mathematical formalism?
Gist of Idea
If it can't be expressed mathematically, it can't occur in nature?
Source
Werner Heisenberg (Physics and Philosophy [1958], 02)
Book Reference
Heisenberg,Werner: 'Physics and Philosophy' [Penguin 1989], p.30
A Reaction
This has the authority of the great Heisenberg, and is the ultimate expression of 'mathematical physics', beyond anything Galileo or Newton ever conceived. I suppose Pythagoras would have thought that Heisenberg was obviously right.