Ennead I.8 was written not long before Plotinus’ death in 270 AD, at a time when he was particularly concerned with ethical issues. The treatise’ primary purpose is to argue that evil is not intrinsic to the soul, but since Plotinus always considers ethical issues within a metaphysical framework, it includes an account of the ontological status of matter. Plotinus does his best to preserve a belief in the dependence of all things on a single, supremely good First Principle while admitting that there is evil in the world. He offers a subtle account of the origin of evil in the soul as caused not by either the soul or matter on its own but by the combination of the two.

Sheppard shows how Plotinus is responding to ideas found in Plato, Aristotle, the Stoics, and Middle Platonism as well as to the challenge presented by Gnosticism, and argues that the views expressed in I.8 are not inconsistent with what Plotinus has to say about matter and its generation elsewhere. She further considers the criticisms of Plotinus’ views put forward by Proclus and concludes that, despite its weaknesses, Plotinus’ account remains an ingenious attempt to defend monism and the essential goodness of the soul while recognizing the existence of evils. 

Plotinus was a Platonist, committed to expounding the doctrines put forward by Plato some seven centuries earlier. He was born and educated in Egypt, where he studied the teachings of Plato under the guidance of Ammonius Saccas. He came to Rome in 244 CE and built up a circle of followers devoted to studying Plato through Plato's own works and those of philosophers, both Platonist and non-Platonist, of the intervening centuries. From his fiftieth year Plotinus himself wrote down, in Greek, the findings of the seminars, and these writings were later edited by one of his pupils, Porphyry, and published in six groups of nine treatises entitled the Enneads (from the Greek word for nine – ennea).