The Oxford Dictionaries named “post-truth” as their 2016 Word of the Year. It must have sounded alien to scientists at the time. Science’s quest for knowledge about reality presupposes the importance of truth, both as an end in itself and as a means of resolving problems. How could truth become passé? For philosophers like me, post-truth also goes against the grain. But in the wake of the 2016 U.S. presidential election and all that has happened since, author Ralph Keyes’s 2004 declaration that we have arrived in a post-truth era seems distressingly plausible.