 To fully appreciate what is at issue in the possibilism-actualism debate, as well as its framing in those terms, it is important to see its origins—more generally, the origins of the bi-modal conception of being—in the ancient, and vexing, philosophical problem of  non-existent objects.  Inklings of the bi-modal conception arguably trace back to the dawn of western philosophy in the goddess’s enigmatic warning to  Parmenides  not to be deceived by the “unmanageable” idea “that things that are not  are”.[6]  It finds clearer expression in Seneca’s description of the Stoics, for whom being included both physical objects and “incorporeals” (ἀσώματα) that “have a derivative kind of reality” (de Harven 2015: 406):