Natura e funzione della phantasia nel De signis di Filodemo

This study analyzes the nature and function of phantasia in Philodemus’ De signis. While terms such as phantasia, phantastikos, and phantasma appear only sporadically—primarily in the initial fragments associated with a lost treatment of Epicurus’ Canon—their role within Epicurean epistemology remains crucial. By contextualizing Filodemus' usage within Epicurus’ Letter to Herodotus (§§ 49–51), this paper argues that phantasia carries a specific technical meaning: a representation stemming from the perception of an object via its eidola. Beyond its logical and epistemological significance, this physical mechanism serves an ontological function by grounding sign-inference (semeiosis). Focusing in particular on Fragment 1 of De signis, this paper demonstrates how the physiological process underlying representation forms the necessary foundation for apprehending the similarity between observable phenomena (signs) and unobservable entities (adela), thereby validating the reliability of sign-based inference.