Plotinus: The Most Famous Neoplatonist & His Radical Metaphysics

What are the most fundamental concepts with which we should think about the world? This question represents the central concern of metaphysical philosophy. In spite of its evident difficulty, Plotinus’ metaphysics has proven especially influential as inspiration and provocation for the metaphysics of later philosophers. This article begins by explaining the context for Plotinus’ philosophy, along with some of the difficulties with placing Plotinus in the history of philosophy. We then discuss the three central principles of Plotinus’ metaphysics. The article then concludes with a discussion of the distinction between being and oneness in Plotinus’ philosophy.

Understanding a philosopher and their work always requires an understanding of their influences and, in turn, the origins of their ideas. Few philosophers require so much context in order to be understood as Plotinus.

Equally, there are precursors to philosophy’s subsequent obsession with its own canon in the reception of Plotinus. Interest in his philosophy has doubtless suffered as a result: it is hard to know where he belongs on a philosophy curriculum: is he the last ancient philosopher? The first medieval philosophy? The greatest Roman? Does he really belong to an Egyptian tradition?

The relationship between Plotinus’ philosophy as it has come down to us, his perception of his own philosophy in relation to preceding philosophers, and the interpretation of his philosophy must precede any introduction to that philosophy. The main reason for this is that our understanding of Plotinus’ philosophical project is crucially determined by the relationship between it and that of preceding philosophers: Plato (naturally, as Plotinus is a Neoplatonist), but also Aristotle, whom Plotinus understood above all as an adherent of Plato’s (albeit a critical one), rather than as presenting alternative philosophy as such.

Plotinus considered himself a Platonist, and likely had access to both Plato and Aristotle’s original writings, but often appears to accept Aristotle’s interpretations of Plato as the last word, even as such interpretations lead directly to Aristotle’s criticisms of Plato. This isn’t to say that Plotinus didn’t see the conflict between Aristotelian and Platonic thought at various points: Plotinus is often, in effect, for Plato, and against Aristotle. Yet, at other times, he adopts Aristotelian concepts and terminology.

Another complication is that Plotinus’ more direct influence was a philosopher called Ammonius, with whom he studied for a decade and whose work Plotinus taught exclusively for a further decade. Inconveniently, Ammonius appears to have written nothing down, and we cannot be certain how far Plotinus’ mature philosophy reflects or fails to reflect the teachings of his one-time master.

Further, Plotinus’ writings appear to have been “occasional;” they are usually responses to issues raised in the course of his teaching duties, replies to critics, and so on.

In a certain sense, this poses similar interpretative difficulties to those we have with Plato. Plato’s philosophy is set out by Socrates, and it is framed as a record of organic conversations which happened to have philosophical value. In other words, both Plotinus and Plato do philosophy in response to discursive situations which they have not themselves constructed out of nothing (or at least, which they go to great pains to imply they have not constructed them out of nothing).

To put it in simpler terms, it’s hard to know where Plotinus stands on a philosophical issue in general when his philosophy is constituted by occasional writings. He does not state his definitive views very clearly.

Plotinus’ Three Principles: The One, The Intellect, and The Soul 

Any explanation of Plotinus’ philosophy will undoubtedly have to proceed from the three fundamental principles of his metaphysics. These are: “the One,” “the Intellect” and “the Soul.”

These three principles are sometimes referred to as “hypostases,” meaning “extra-mental existents,” or simply existents, but we can think of them as “principles” for various reasons. They are explanations and not merely postulates as the term “existent” might seem to imply. They are paradigms—they constitute ways of thinking, the context for further thinking and therefore further philosophy. Also, they are causes—they lead to the occurrence of certain further things. These are not merely intellectual tools but in some sense “real” principles of reality. Indeed, there is a strictly causal order to the principles: “the One” causes “the Intellect”, and “the Intellect” causes “the Soul.”

The first principle—the One—follows an intuition that has incited many philosophical arguments and, indeed, whole philosophies. It is this: the complexity we observe in the world around us must, ultimately, be founded on a principle or entity which is utterly simple.

Plotinus is not alone in deriving a principle of absolute simplicity from the existence of complex things. This ultimate simple thing must, as Plotinus explains, be absolutely self-sufficient. The argument is, at least on the surface, a straightforward one: what is not “first” relies on that which comes before it for its existence, and that which is not simple relies on the simple things which constitute it for its existence. We can imagine a kind of infinite regression of these properties that gets us, eventually, to the principle of “the One.”

To be simple is to be without any parts, indeed without any predicates (meaning, without any qualities, any descriptions which can rightly be attributed to it). Plotinus is even skeptical that the term “the One” is quite right—it is only an approximation, as strictly speaking, the One cannot be given a name or any form of description which captures its perfect simplicity.

The natural response to a principle without predicates is to ask whether this does not in turn preclude us from even saying that it exists. To put the question another way, does the redundancy of description spill over into a redundancy of the principle in itself? Does the existence of “the One” imply that it has at least one predicate (it exists rather than not existing)?

Plotinus, for his part, holds that “the One” is “beyond being.” We might therefore suggest that, in whichever sense it can be said to exist, the existence of “the One” is of an utterly simple kind. Further objections then follow a similar route: if “the One” is beyond predication, and beyond being, is it not also beyond human comprehension? Plotinus distinguishes “being” and “oneness,” in direct contradiction of Aristotle, who claims that “being a man,” ”one man,” and “a man” are, in effect, different ways of saying the same thing.

Being and Oneness

Plotinus claims that the distinction between being and oneness goes beyond our manner of speaking. One way this view can be characterized is according to the difference between the characteristics of a certain thing that constitute it, and the entity itself. If we were to write down the list of qualities that make up an apple (it is red, green, or yellow, it is round, it is shiny), it seems problematic to suggest that there should be “is an apple” on that list.

In fact, there are various problems with putting “is an apple” on our list of qualities that constitute the apple, but we can stick with one for now. What does “is an apple” mean? We could say that it is an abbreviation of the other various qualities which constitute the apple: that is, the color, the shape, the shininess, and so on. So, having teased out the meaning of “is an apple,” does our list repeat itself? Isn’t the quality “is an apple” obsolete?

We might therefore think that the property of unity, or oneness (insofar as it is the oneness of a specific thing), is redundant. Clearly, Plotinus is using the term “being” in a specific way: this is not the only way of defining being. The effect of all this is to show that being is distinct from oneness.

To make sense of Plotinus, we have to be willing to conceive of the distinction between being and oneness as tracking quite closely with that between essence and existence. Lloyd P. Gerson, whose interpretation of Plotinus has proven invaluable for the purpose of writing this introductory article, justifies this conflation with several interpretative arguments.

First, he observes that unless the distinction between being and oneness approximately follows the distinction between essence and existence, then there seems to be little that constitutes the former distinction. Second, Gerson observes that Plotinus holds that the first principle (“the One”) preserves all things in existence. It is therefore external to the composition of qualities that constitute a given entity—this corresponds to the pure existence of the object. Third, Gerson observes that whether or not it is in some sense anachronistic to distinguish being and oneness according to the distinction between essence and existence, it serves to elucidate Plotinus’ theory well for the modern reader.

It is perhaps worth concluding on a similar note. Plotinus’ philosophy is demanding for a variety of reasons: it is conceptually systematic without being organized as such, it involves an array of technical terms which require a great deal of context even before being subject to translation. And yet Plotinus’ metaphysics in particular has proven extremely influential for a wide array of philosophers and theologians since; its demands are well worth meeting.