All of philosophy, Whitehead famously quipped, is a footnote to Plato. Not only does Plato’s corpus cover almost everything that we have come to call “philosophy,” but many great (and minor) thinkers have spent careers writing commentary on Socrates’s famous student—footnotes to Plato. Beginning with the Hellenistic schools devoted to Plato and Aristotle, there were the so-called Middle Platonists, including Plutarch; the Neoplatonism of Plotinus in the third century; Plotinus’s student and biographer Porphyry; the influential Neoplatonism of Porphyry’s student Iamblichus; a small crowd of Gnostics who were influenced especially by the cosmology found in the Timaeus, and the Platonists who read Plato in Latin, such as Cicero. These are just some of the Platonic thinkers who appear in Peter Adamson’s magisterial Philosophy in the Hellenistic and Roman Worlds, Volume 2 of his History of Philosophy Without Any Gaps. In addition to their commentaries on Plato, or in some cases over the course of their commentaries, many also managed to write original philosophy themselves.
This is especially interesting in light of the fact that Plato himself, Adamson takes pains to show, wasn’t always such a hardcore Platonist. If you look carefully through his works, for example, you won’t find an entirely satisfying or complete explanation of his theory of Forms, despite that theory being one of his most famous contributions to philosophy. For a more comprehensive explanation of how forms might actually interact with each other and the world one needs to look to Plotinus, whose Enneads, Adamson writes, were the most influential response to Plato, in part because his reading was so original. Plotinus did not consider himself a Neoplatonist, of course; in all likelihood he did not even believe that what he was doing was all that original. He was, begrudgingly according to Porphyry, merely explicating and clarifying Plato for the sake of his students. (It was begrudging because, like Plato himself, Plotinus thought of writing as a kind of shadow of speech, itself a kind of shadow of thought.)
One can see how Plotinus is a thinker after Adamson’s own heart, because his Enneads are nothing less than an attempt to fill in the Platonic gaps. We know that there is a Form for the Good and for Justice, and most likely Virtue. But things get hairy when we learn that there is a Form for the chair I’m sitting on, a Form for the Mac computer I’m typing on, and so on. Plato’s metaphysics get crowded pretty quickly as soon as you start to unpack it. The beauty of Plotinus, at least as I understand him, is that he simplifies the notion of Forms into three that encapsulate all of nature: The One, Mind, and Soul, with the latter two emanating from the first.
Though Adamson devotes chapters to Stoicism, Epicureanism, and other currents in post-Aristotelian philosophy, I single out Plotinus because his appearance marks the climax of what I take to be the central story of Adamson’s book: Platonism after Plato. Plotinus’s concept of a central, nearly undefinable entity that cannot be comprehended by the senses was his peculiar take on Plato, but it had a major influence on one of the most intriguing, enigmatic thinkers Adamson discusses: Pseudo-Dionysus. Pseudo-Dionysus promulgated what has come to be known as apophatic, or negative, theology, in which God can only be described by what He is not, rather than what He is. Pseudo-Dionysus’s Divine Names is a systematic approach to an understanding of God in which every Biblical name or description given to Him (good, light, enthroned, even extensional images such as a front and back, etc.) is shown first to be metaphorical and then finally insufficient. God is not merely “good.” The Steelers of the '70s were good. God is “hyper-good,” i.e., he transcends all notions of good. In the end, however, Adamson notes that we must take a page from Wittgenstein and simply pass over the topic in silence.
While Pseudo-Dionysus reveled in the unknown and wrote a comparatively small body of work, Augustine composed a massive corpus covering much of the same ground as Plato. His epistemology echoes Plato’s Meno, as Augustine believes that we can only find true knowledge “by turning towards an inner standard of truth” and not from human instruction. Furthermore, just as the Plotinian concept of a tripartite metaphysics probably contributed to present-day notions of the Trinity, the Augustinian concept of a soul that pre-exists the body and is in most ways superior to it is more or less the pre-philosophical image of the soul for most of us raised within the Judeo-Christian worldview. It too comes from Plato.
These are just a few of the treats to be found in the many-course meal Adamson serves up in the second volume of his series, which is a collection of scripts adapted from his podcast. Not all of it is about Platonism, of course. Boethius, whose chapter ends the book and includes a quick introduction to medieval philosophy, commented extensively on Aristotle and less on Plato. Boethius also took a page from the Stoics. When he’s not discussing logic or theology in Consolation of Philosophy, which he wrote while awaiting execution at the hands of a Western emperor after the fall of Rome, he borrows heavily from Seneca and Marcus Aurelius.
–David Crohn is a writer and teacher living in New York City.