Did you ever wonder how we arrived in a post-truth era, where "alternative facts" are substituted for actual facts and feelings are given more weight than evidence? In Post-Truth (MIT Press, 2018), Lee McIntyre '84—a research fellow at the Center for Philosophy and History of Science at Boston University and an instructor in ethics at Harvard Extension School—explores the long history of the phenomenon . . . and what's different this time around. Q: Many people think that post-truth is a new idea, borne of Brexit and the 2016 U.S. presidential election, but in your book, you explore the history behind the…