Truth is one of the most complicated concepts in the history of philosophy, and much of the research and public debate about post-truth has a sociological approach to the problem, and implies a correspondence or, especially, coherence theory of truth, where, roughly, words correspond to an accepted or mutually available reality to be examined and confirmed, or (in coherence theory), truth is not just about one statement but a series of statements that cohere.[7][8] Several academic experts note that the emphasis on philosophical debates about truth have little to do with the concept of post-truth as it has historically emerged (not in philosophy but) in popular politics (see post-truth politics). As the philosopher Julian Baggini explains: