In the narrative of Tlon, Uqbar, Orbis Tertius through the articulation of the semantic import of two quotes of the literate culture, it is unfolded a potent deconstruction of the meta-narratives of modern metaphysics as a visionary aesthetic of the fantastic fiction. This paper will try to reveal as a terrorist attack the audacious epistemological thesis contained in the statement: "the metaphysics is a branch of the fantastic literature", which amounts to the lifting an ontological iron curtain due for its inversion of the hierarchy of the speeches within modern knowledge. The themes of the mirror and of the encyclopedia will be analyzed, understanding both as semiotic devices of mirror-like representation and writhing of the world, respectively, and as an irony towards the encyclopedic project of the modern age and also towards the Argentine of the National Organization. All of these allow us to suggest an epistemologic turn toward an aesthetic-narrative paradigm in Borges' post-modern view about the fantastic.