I don't know what Feynman was talking about, when he said that. Much philosophy of science is bullshit, in my considered opinion. But Kuhn's and Popper's work, for example, are not. And I'd be very surprised if Feynman claimed that they were.

Also, maybe Feynman was just fucking with the interviewer. He was like a physics version of Lenny Bruce. But warmer, like Bill Clinton.