There's a picture of two people on slide seventy-two, one of whom is one of the most famous historians in the 20^th century, E.H. Carr, and the other of whom is a famous economic historian at the University of Chicago, Robert Fogel. They could not have more different attitudes toward the importance of counterfactuals in history. For E.H. Carr, counterfactuals were a pestilence, they were a frivolous parlor game, a methodological rattle, a sore loser's history. It was a waste of cognitive effort to think about counterfactuals. You should think about history the way it did unfold and figure out why it had to unfold the way it did—almost a prescription for hindsight bias.

Robert Fogel, on the other hand, approached it more like a scientist. He quite correctly recognized that if you want to draw causal inferences from any historical sequence, you have to make assumptions about what would have happened if the hypothesized cause had taken on a different value. That's a counterfactual. You had this interesting tension. Many historians do still agree, in some form, with E.H. Carr. Virtually all economic historians would agree with Robert Fogel, who’s one of the pivital people in economic history; he won a Nobel Prize. But there’s this very interesting tension between people who are more open or less open to thinking about counterfactuals. Why that is, is something that is worth exploring. 

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PHILIP E. TETLOCK [2] is the Annenberg University Professor at the University of Pennsylvania, with appointments in Wharton, psychology and political science. He is co-leader of the Good Judgment Project [3], a multi-year forecasting study, the author of Expert Political Judgment and (with Aaron Belkin) Counterfactual Thought Experiments in World Politics, and co-author (with Dan Gardner) of Superforecasting: The Art & Science of Prediction  [4](forthcoming, September 2015). Philip Tetlock's Edge Bio Page [2].