Most of the history was "pre-truth age". By the intermediate value theorem there surely was a brief, infinitesimal period of "truth age". /jk I guess the word

Most of the history was "pre-truth age". By the intermediate value theorem there surely was a brief, infinitesimal period of "truth age". /jk I guess the word "post-truth" means the lack of truth as an objective or goal, not the lack of truth by itself.