T he historian Rob Boddice sat cross-legged on his couch in Montreal on a frigid day last winter and conjured for me the image of a medieval carpenter, hammering away in his workshop. “Imagine this guy; he’s building a table,” he said. Suddenly the carpenter misses the nail and bangs his thumb instead. “What did that feel like for him?” Boddice asked. I stared for a few seconds while Boddice smiled encouragingly, as if he’d just asked me to solve a quadratic equation in my head. “I guess it