I like the second paragraph in this blurb about economic analysis really being a careful reading of history. At this late juncture in my career I regret not having more training in that regard, so I spent a disproportionate time theorizing and not enough time on the available evidence. Sargent (in his early paper with Neil Wallace) vexed us in first year macro in grad school. It's good to see he's come around from the thinking in that paper. At a seminar he gave at Illinois some years back I flummoxed him unintentionally, by asking him whether he knew if the equilibrium of his model was unique. He had assumed that, but hadn't proved it. I was too shy to chat with him about it after the talk. It probably won't ever happen, but if the opportunity were to avail itself, I'd like to chat with him now. I particularly would want to know whether his political views have changed along with his economics.