If they are “not idiots,” who are? Contrary to popular opinion, an “idiot” is not simply a microcephalic or a profoundly brain-injured person. Rather, the term derives from the Greek word “idios” meaning “private” or “self-absorbed.” An idiot is thus anyone who is impervious to reason, logic, and evidence. For this reason, flat earthers fit this category, but so do climate change deniers. All these are idiots, who have abandoned reason and evidence to cling to preconceived beliefs that violate both.