philosophy

Heisenberg's recollection of his first meeting with Bohr:

For the first time I understood that Bohr's view of his theory was much more sceptical than that of many other physicists - e.g. Sommerfeld - at that time and that his insight into the structure of the theory was not a result of a mathematical analysis of the basic assumptions, but rather of an intense occupation with the actual phenomena, such that it was possible for him to sense the relationship intuitively rather than derive them formally.

Thus I understood: knowledge of nature was primarily obtained in this way, and only as the next step can one succeed in fixing one's knowledge in mathematical form and subjecting it to complete rational analysis. Bohr was primarily a philosophyer, not a physicist, but he understood that natural philosophy in our day and age carries weight only if its every detail can be subjected to the inexorable test of experiment.

It seems that both of these great physicists held views which resonate strongly with Feyerabend's descripion of science. The continue relevancy and progress of physics does seem to depend on the embrace of many means of validating a scientific theory beyond the purely formal.