Ennead IV.7 is a very early treatise (second according to Porphyry’s chronological table), and unlike the many treatises devoted to attempts at untangling various issues Plotinus found problematic in Plato’s thinking, this one presents the teachings of the other main schools current in Plotinus’ day: the Stoics, Epicureans, Pythagoreans, and Peripatetics, all of whom presented soul as something material or as contingent upon material soul, and so as being neither truly immortal nor imperishable.

It includes observations on many mainly Stoic doctrines on perception, memory, sensation, thought, virtue, powers of material bodies, mixture and reproduction (Chapters 1–8³); on Pythagorean attunement (8⁴); and on Peripatetic entelechy (8⁵). In Chapters 9–10 Plotinus presents, in broad terms, Plato’s doctrines on soul’s immortality—mainly that of the individual soul, but a fortiori that of the soul of the cosmos. These chapters offer some of Plotinus’ most powerful prose.
He is not concerned to prove the soul’s immortality—that was an uncontroversial tenet of Platonism, to be taken for granted. In this treatise Plotinus is laying down the in­disputable foundations for his later writings.

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).