As a graduate student it was with great pleasure that I learned that John Watkins had decided to thank me publicly for helping him with a paper on Kuhn's view.¹ The help, such as I could give, was in Popper's seminar, twenty-five years ago. Watkins himself, and several others, contributed much more to the seminar than I did. (The seminar was run on the principle — to repeat J.O. Wisdom's quip — "thou shalt not speak whilst I interrupt"). Watkins was not just kind but generous in thanking me and I appreciated it very much then, as a mere graduate student. But over the years, I find that I appreciate it even more, especially as I compare it with practice common among philosophers. It is ironic that by the time Watkins' paper appeared (something resembling his view had by then already become the official reading of Kuhn's views among philosophers of science) my own views about Kuhn's book had changed.