Another quickie reply, appropriate given you are at Harvard, is that "the history of error" story assumes that the sciences are cumulatively progressive, which since Thomas Kuhn is, to say the least, a contestable proposition, and he wrote with the physical sciences in mind. You might add as a stinger that Kuhn was influenced by James Conant, who (I suspect you may need to explain) was a former Harvard President. The first sentence of Kuhn's Structure of Scientific Revolutions reads: "History, if viewed as a repository for more than anecdote or chronology, could produce a decisive transformation in the image of science by which we are now possessed." That's a nice line, no? Bruce Caldwell