Post-Truth - I Feel Like Alice in Wonderland

Nothing is as it seems. What I know to be real, believe to be true built on my reliance on facts is apparently passe. It's official: Truth is dead. The latest edition of the Oxford Dictionary has made it official. Post-truth now has an explanation: "objective facts are less influential in shaping public opinion than appeals to emotion and personal belief." Of course, that definition is post-truth, so it may or may not be true. The Oxford Dictionary may be a propaganda tool written by the liberal media, the alt-right, conservative pundits, or some unknown Russian hacker. And, therein lies the problem that has me scratching my head. If "truth" or "reality" are no longer what they have always been, how does one separate the wheat from the chaff? How does one construct a rational response to events when rationality is under attack? Is Mars really populated by little green men (and women)? If enough people on the Internet claim it to be so, then does tha...