This article explores the semiotic notion of “reality” by questioning its ontological status and reframing it as a symbolic and cultural construct. Starting from the absence of “reality” in Greimas and Courtès’ Dictionnaire, the discussion highlights how semiotics distances itself from metaphysical concerns, conceiving reality instead as an effect of sense. Through an examination of cognitive science (Lotto, Hoffman), theoretical physics (Rovelli), and classical sociology (Berger e Luckmann), the paper emphasizes the role of perception, relational models, and social practices in shaping what is collectively experienced as “real”. Special attention is given to Greimas’ concept of the “natural world” as a semiotic black box, which structures human existence within a pre–sensed universe and produces the “referential illusion”. Finally, the article addresses the contemporary urgency of phenomena such as post–truth, conspiracy theories, and fake news, situating them within the broader anthropological framework of symbolic thought. Drawing on Lévi–Strauss and Barthes, it argues that belief in “alternative realities” should not be reduced to ignorance or technological illiteracy but understood as part of a universal symbolic logic: a process of mythopoiesis that continuously generates socially shared realities.