Unity, intellect and the life of the soul

A melody and its notes

Imagine a pianist playing a familiar melody, then rearranging its notes. Every note is still there, but the melody has gone. A list of the notes, however complete, cannot explain what made them one recognizable thing.

The puzzle is one of plurality: how can many things make up a unity? Aristotle’s explanations distinguished material from form, the organization that makes something the thing it is. Plotinus presses the demand for an account of unity far beyond any particular object.

Plotinus was a third-century CE philosopher who studied in Alexandria and taught in Rome. He developed the Platonic tradition through arguments with Aristotle and other schools; Neoplatonism is a later name for the tradition with which he is associated. [2]

Why seek a first principle?

Go back to the melody. It needs its notes in a certain relation, but each note also has a definite identity of its own, and even a mere collection needs things that can be told apart and each counted as one. Unity is already at work in any account of the many.

Plotinus looks for a first principle, that on which other things ultimately depend for their existence. His search rests on a demanding premise: the ultimate explanation of anything multiple must come from something simpler. A proposed source that itself contained a plurality would leave its own unity unexplained. On this premise, the source of all unity must be wholly simple, without parts or internal distinctions. [1]

Paul Kalligas reconstructs this priority of the simple as a central principle of Plotinus’s thought, and it is a commitment we are free to question. The melody shows that a unity needs organization; it does not show that every unity depends on one separate source, or that explanation must end in absolute simplicity. To reach that conclusion, we would have to defend Plotinus’s demand for a simple ultimate explanation. [2]

Why Intellect cannot be the first principle

Could the first principle be a mind that understands everything?

Recall Plato’s Forms: what beauty or justice itself is, as distinct from the particular things that are beautiful or just. Plotinus places the Forms within Intellect, an eternal activity of understanding, and treats them as intelligible, that is, accessible to understanding through reason. In Intellect, thought and what it understands belong to one living reality, so Intellect does not inspect the Forms from outside or slowly learn about them. [1]

Yet Intellect still contains distinctions. Beauty is distinguishable from justice, and even when thought understands itself, we can tell the thinking apart from what is thought. Because Intellect holds many distinct objects of understanding together, Plotinus concludes that it too depends on something simpler. Giving the first principle perfect knowledge would not remove the multiplicity that started his question. [1]

What does Plotinus mean by the One?

Plotinus calls this first principle the One, and also the Good. It cannot be an ordinary highest object, such as the largest star or the cleverest mind, because anything of that kind would have a definite nature and features that could be told apart. The source he proposes comes before any such division into definite beings. [1]

That is why he places the One beyond being and beyond Intellect. He does not mean a blank absence. He gives the One the extraordinary role of making every definite thing possible, while denying that it is itself one of those things. Calling it “one” points to the absence of multiplicity; it does not count one more item in the universe.

This raises a real difficulty. How can something beyond ordinary description explain anything at all? Plotinus’s account has to make that role intelligible.

Emanation without a beginning in time

Emanation is Plotinus’s name for the way further reality depends on this source. He compares it to light radiating from the sun or heat from a fire: what proceeds from a source depends on it without using it up. [1]

The imagery can mislead. In V.1.6 he expressly rules out generation in time. The One does not wait, draw up a plan and then manufacture the world, and it does not break into pieces. “First” concerns dependence, not the earliest event.

On this account, Intellect proceeds from the One and turns back toward it, and through that contemplation it becomes a definite unity. Return here means the relation to a source through which something becomes what it is, not a journey back through space. Proceeding and returning are aspects of dependence, not two moments in a cosmic history. [1]

The soul’s direction

Soul comes next. It depends on Intellect and gives life and order to bodies. Plotinus’s account includes the soul of the cosmos as well as individual souls, so “soul” reaches well beyond our private feelings. Our kind of thinking moves from one thought to the next, and Plotinus sets it apart from Intellect’s complete, unchanging understanding. [1]

For us, return is also a matter of how we live. Plotinus thinks that absorption in external objects can make us forget our own nature, so he asks the soul to examine itself and attend to the understanding on which its reasoning draws. In V.1.12 he compares this attention to listening for one sound while setting the others aside.

The inward turn asks far more than a pleasant break from distraction: it seeks a reality on which, he thinks, we already depend. We can still ask how inward attention could establish that the reality it seeks exists. [1]

Argument and experience

Plotinus also reports experiences. At the opening of IV.8 he describes turning inward, living a higher life and a union with the divine. Returning to ordinary reasoning, he asks how his soul came to be embodied. The experience starts an inquiry; it does not close one. [1]

A report of this kind works differently from an argument, whose premises and steps we can examine. With a report we can ask what happened, how Plotinus understood it and whether his interpretation is warranted. Granting his sincerity would not establish the whole account of One, Intellect and Soul, and neither would a powerful experience of our own. Nor do these passages entitle us to identify every later mystical tradition with his project.

Try the explanation

One student says, “The One must be a perfect musician who knows every melody and built the universe.” Another replies, “I felt completely absorbed while listening, so I have proved Plotinus right.” What would Plotinus question in the first claim? What is missing from the second?

Read a possible response

The first student has described a mind, not the One. A perfect musician still has many distinct objects of knowledge, so even perfect understanding would leave the multiplicity for which Plotinus seeks a simpler source; and building the universe suggests a decision and a process in time, where his account concerns dependence with no first moment of production. The second student has reported an experience and supplied an interpretation of it. They have not explained why absorption establishes the existence of the One. Nor did our opening melody prove that every unity requires an absolutely simple cause: understanding Plotinus includes seeing which of his premises still need a defense.

Carry this forward

Plotinus’s question is an ambitious one: what must reality be like for there to be unified things, and understanding, at all? His answer combines argument, image and reported experience, and each needs to be weighed on its own terms. In Time, will and the inward turn, Augustine examines remembering and willing within a North African Christian life. His inquiry also turns inward, and we will ask of it what we asked of Plotinus: what do its arguments establish, and what rests on personal testimony?

Sources and limits

[1] Plotinus, Enneads, translated by Kenneth Sylvan Guthrie in Plotinos: Complete Works, volume I, Comparative Literature Press, copyright 1918; Project Gutenberg ebook 42930, for the account of the One, Intellect, Soul and return. The following were read:

• Treatises: the supplied V.1.1–12, pp. 173–192; V.2.1–2, pp. 193–196; and IV.8.1, pp. 119–121.
• Editorial matter: the Foreword, relevant notes 149–158 and 216–277, and the complete Transcriber’s Notes.

The title, imprint, volume and chronological concordances were checked.

In V.1.6, the Roman numeral identifies the Ennead, the next number the treatise and the last the section. Guthrie arranges the treatises chronologically, which is why these passages all occur in his first volume; his “Intelligence” is called “Intellect” here. The passages support different parts of the lesson:

• Unity and generation: V.1.4–7.
• The soul and attention: V.1.1–3 and 10–12.
• The first-person report: IV.8.1.

The web transcription normalizes some spelling and punctuation and combines the original footnotes and endnotes into one numbered sequence. V.2.1 includes an ellipsis and a fragment whose placement Guthrie questions in note 270, and the transcriber reports a missing anchor for note 267. The lesson’s main explanation of generation rests on V.1.6. These editorial and transcription limits were recorded, but no source-page images were inspected and no Greek text was compared. No whole volume or complete Enneads was read.

[2] Paul Kalligas, “Plotinus”, Stanford Encyclopedia of Philosophy, first published 25 September 2024, for historical context and a specialist reconstruction of the first principles. The complete §§1, 5, 6 and 7 were read; the whole article and the works it cites were not. A scholar’s reconstruction is distinct from an independent review of this lesson.

The melody, the students and the response are original teaching material; the sun, fire and listening images adapt the checked Plotinus passages. The connections to Plato and Aristotle reuse the evidence recorded in their lessons. No systematic second-translation comparison, original-language collation, independent specialist or learner review, or learner timing was performed, and the philosophical and interpretive questions the lesson raises remain open.