You wouldn’t think that a defense of reason, science, and humanism would be particularly controversial in an era in which those ideals would seem to need all the help they can get. But in the words of a colleague, “You’ve made people’s heads explode!” Many people who have written to me about my 2018 book Enlightenment Now say they’ve been taken aback by the irate attacks from critics on both the right and the left. Far from embracing the beleaguered ideals of the Enlightenment, critics have blamed it for racism, imperialism, existential threats, and epidemics of loneliness, depression, and suicide. They have insisted that human progress can only be an illusion of cherry-picked data. They have proclaimed, with barely concealed schadenfreude, that the Enlightenment is an idea whose time has passed, soon to be killed off by authoritarian populism, social media, or artificial intelligence. This month’s publication of the paperback edition of EN in the US and UK is an occasion for me to weigh in on the controversies that have flared up in the year since …