Plotinus' Unaffectable Matter

In this paper, I investigate the foundations of Plotinus’ innovative theory that prime matter is unaffectable. I begin by showing that Plotinus’ main arguments for this thesis (in Ennead 3.6) all rely upon the controversial assumption that the properties prime matter underlies are not properties of prime matter itself. It is then argued that prime matter’s privation of sensible qualities has its conceptual basis in an idiosyncratic understanding of form-matter composition generally, and its primary doctrinal basis in Aristotle’s critical reports on the Platonists’ substratum in Physics 1.9. While Plotinus finds Platonic authority for unaffectible matter in the Receptacle passage of the Timaeus, it is Aristotle’s testimony that provides the crucial impetus for reading that text in this way. On this basis, Plotinus develops a Platonist conception of form’s inherence in matter with distinctively non-Aristotelian features.