Author Paul H. Nahin tells in Introduction to his new book how on several occasions the Nobel Prize winner Richard Feynman spoke condescendingly of mathematics. Nahin suggests that "Mathematics is trivial, but I can't do my work without it" may have been a joke and should not be taken too seriously. He may be right as Feynman was a rather good mathematician. Among many other achievements he is well known for the eponymous "Feynman integral" - the idea of which may shed light on Feynman's attitude towards mathematics. Feynman integral replaces in quantum mechanics the notion of a single trajectory with an integral over all possible trajectories to define a quantum amplitude. The "integral" in Feynman's view is just a tool for a description of quantum theory.
Nahin tells a story (p. xxiv) of an episode in which Feynman "got at least as good as he gave."
The great probabilist Mark Kac (1914-1984) once gave a lecture at Caltech, with Feynman in the audience. When Kac finished, Feynman stood up and loudly proclaimed, "If all mathematics disappeared, it would set physics back precisely one week." To that outrageous comment, Kac shot back with that yes, he knew of that week; it was "Precisely the week in which God created the world."
- P. H. Nahin, Number-Crunching, Princeton University Press, 2011