I dreamt that I was asked in front of a large audience for an example of how a medieval scientist would think. I did not hesitate for a second. “A bird has wings,” I mimicked his argument, “and a man has arms, which is why we cannot fly.” Here I paused for effect. “However,” I continued, “a man’s arm has the same bones as a bird’s wing.” I paused again. “Add some feathers and some training,” I concluded, “and a man, too, can fly.” After a warm applause, I explained that the medieval scientist was more or less right about the bones, but that he could not understand that the entire body of a man was not good for flying. To begin with, it was too heavy. The audience was quite satisfied with my example, and I felt kind of pleased with my impromptu performance. When I woke up, I realized that the whole story was entirely made up. I had not a single anecdote worth telling. In fact, I had no idea whatsoever how a medieval scientist would think. In my dream, I was he, instead.