What exactly is philosophy of science – and why does it matter?

There’s a quote attributed to Richard Feynman, and repeated by Steven Weinberg, which one could interpret in a couple different ways: “Philosophy of physics is about as useful to physicists as ornithology is to birds.” What do you make of this comment?

http://www.routledge.com/philosophy/articles/what_exactly_is_philosophy_of_science_and_why_does_it_matter/