Wallace Stevens’ idea of supreme fiction is one of the most important poetic concepts that helps to get insights on the relationship between reality and imagination. Reality does not consist only of objective things; inevitably it needs to be intervened by human imagination. The idea of imagination getting involved in reality entails the fictive aspect of reality. This perspective resonates with Jean Baudrillard’s concept of simulation and Yuval Harari’s idea of “the belief of fictional entities.” It is because of language as a sign that reality consists partly of fictional things. The ideas of language, sign, and reality are all those three thinkers have in common. Especially, in the age of post-truth when it is getting harder to clearly discern between truth and untruth, Stevens’ idea of supreme fiction is conducive in realizing truth of the world along with Baudrillard and Harari’s thoughts.