Plotinus describes matter as “evil itself” (I.8.8.37-44; I.8.13.7-14) and as source of evil in the soul (I.8.14). However, those two apparently straightforward statements lead at once to paradox when we learn that matter is nonetheless derived from the One, through the mediation of soul (III.9.3.7-16; III.4.1). And that paradox is only heightened by Plotinus's repeated claim that matter, “primary evil” and “evil per se” (I.8.3.35-40), is also “non-being” (II.4.16.3; II.5.4-5; III.6.7.1-19).

Various attempts have been made to eliminate one or other element in the paradox. Thus Schwyzer claims that matter exists independently of soul and of the One. Rist allows that matter is a product of the soul, but claims that the soul's production of matter is itself an evil act; from which it should follow that at least one evil act is performed by the soul, independently of the presence of matter. While Pistorius claims that matter, according to Plotinus, simply does not exist at all.

None of those interpretations can survive close confrontation with the text of Plotinus. And, conceptually, none of them does justice to the intricacies of Plotinus's thinking.

My own conclusion will be that a production of the non-being that is matter through the agency of one of the lower manifestations of soul is essential to Plotinus's explanation of evil in the world and of evil in the soul. It is true that, here as elsewhere, Plotinus's arguments are highly elliptical, and rely for their cogency on concepts and categories that are alien to modern ways of thinking and that have often only a tenuous relation to the writings of Plato and of Aristotle that are quoted, tacitly or explicitly, in their support.