Yeah, I did my own detective work on it, it's a selective quote from Michael Ruse, from a piece called 'Darwin's Theory: an exercise in Science'. He was questioned about it during McLean vs. Arkansas trial, and claims that he was referring to the views of philosophers rather than scientists, it's
here, about 343 to 347.
From what I gather from that I think he was referring to the once popular notion amongst Popparian philosophers of science that Evolution is not falsifiable; he certainly wasn't making the point that the Quote Miners are trying to string out of it.