On the Intellect

Overview

A short treatise, about twenty pages, written by Abu Nasr Al-Farabi around the same period as his other major works, in the first half of the tenth century. It survives as one of several short essays addressing specific philosophical problems Al-Farabi thought needed clarification before students could tackle the harder Aristotelian texts directly, and it functioned in the Arabic philosophical tradition as something close to a study guide for one of the most obscure passages in Aristotle’s entire corpus, Book III of On the Soul, where Aristotle discusses the active and passive intellect in language so compressed that commentators have never fully agreed on what he meant.

The problem the treatise solves is practical as well as theoretical. Aristotle’s account of intellect had already generated wildly divergent interpretations among the Greek commentators, and different readings had radically different implications for whether anything of an individual person survives death. Al-Farabi’s treatise does not resolve every ambiguity in Aristotle, but it gives the tradition a clear, stable vocabulary and a definite sequence of stages that later philosophers, whether they agreed with Al-Farabi’s specific conclusions or not, could use as a shared starting point.

The treatise’s influence traveled through two channels: directly, as later Arabic philosophers like Avicenna and Averroes read and responded to it, and indirectly, as the vocabulary it established, potential intellect, agent intellect, acquired intellect, passed through Latin translation into the work of Albert the Great and Thomas Aquinas, becoming part of the ordinary technical apparatus of European scholasticism.

The argument

Clearing away confusion about the word. Al-Farabi begins, characteristically, by sorting out ambiguity before proceeding. The word intellect, he notes, is used by ordinary people to mean something like good practical sense or shrewd judgment about worldly affairs. Theologians use it differently, often to mean something like innate moral knowledge or the faculty that grasps self-evident religious truths. Neither of these is what Aristotle meant by the term in his technical philosophical works, and Al-Farabi is explicit that his treatise concerns only the third, Aristotelian sense, drawn specifically from the Posterior Analytics, the Nicomachean Ethics and On the Soul.

This opening move matters more than it might seem. By separating Aristotle’s technical usage from popular and theological usage, Al-Farabi protects the philosophical analysis that follows from being derailed by disputes that belong to a different subject entirely, and he signals to the reader exactly what kind of inquiry is coming.

The stages of the human intellect. The heart of the treatise lays out a sequence, building directly on Aristotle’s brief remarks but developing them into a far more explicit structure than anything in On the Soul itself.

The material intellect, sometimes called the potential intellect, is the bare, undeveloped capacity every human being is born with, a pure receptivity for intelligible forms, comparable to a blank writing surface that as yet bears no writing. It is not yet actually thinking anything; it is only the capacity to think.

The intellect in actuality is what the material intellect becomes once it has actually grasped intelligible forms, abstracted from the images supplied by sense perception and imagination. At this stage genuine thought is occurring, though the intellect that has reached it can still only think about the particular forms it has so far acquired.

The acquired intellect is the highest stage available to human beings in this life, reached when the intellect becomes capable of turning back on its own activity and thinking about thinking itself, grasping intelligibles in a more universal and less materially conditioned way. Al-Farabi treats this stage as the point of closest possible contact, or conjunction, between an individual human mind and something beyond it.

The Active Intellect. None of this sequence, on Al-Farabi’s account, can happen through the individual soul’s own resources alone. Something external is needed to actualize the transition from potential to actual thought, just as an eye with the capacity for sight needs external light before it can actually see anything, and colors need that same light before they are actually visible rather than merely potentially so.

That external agent is the Active Intellect, which Al-Farabi identifies as a single, separate, immaterial substance, not part of any individual human soul, and not multiplied across individuals the way bodies are. In his broader cosmological scheme, inherited from Neoplatonized Aristotelianism, it occupies the lowest rank among a hierarchy of celestial intelligences that emanate from the First Cause and govern the celestial spheres, with the Active Intellect specifically responsible for actualizing intellection and imparting forms within the sublunar world, the region of change and generation that includes human beings.

The light analogy does real philosophical work here. Just as light does not itself become part of the eye or the object seen, but is the necessary condition without which neither can be actually related to the other, the Active Intellect is not absorbed into the human soul but remains a separate cause that makes human thinking possible, illuminating, as it were, both the human intellect’s receptive capacity and the intelligible forms it comes to grasp.

Implications the treatise leaves open. Al-Farabi is more cautious here than some of his successors, but the structure he sets up raises an obvious and consequential question: if the highest human thought consists in some kind of conjunction with a separate, eternal, universal Active Intellect, what does that imply about personal survival after death? If what survives is only the universal Active Intellect itself, unindividuated and impersonal, then something like immortality of a highly abstract kind may be secured for thought in general, but not obviously for any particular thinking person. This ambiguity, present already in Aristotle and sharpened by Al-Farabi’s more systematic treatment, became one of the most contested questions in the later tradition, dividing Avicenna’s more individualist reading from Averroes’ far more radical claim that a single Active Intellect, and perhaps a single material intellect too, is shared by the entire human species.

How to read it

Read Aristotle’s On the Soul Book III, chapters 4 through 5, first, even though it will likely seem obscure and compressed. Feeling that difficulty firsthand is what makes clear why a treatise like this one was needed at all.

Then read Al-Farabi’s treatise slowly, tracking the three stages, material, actual, acquired, as a numbered sequence, and drawing the light analogy out in your own words before moving on. The whole treatise turns on that one comparison.

Notice what Al-Farabi does not settle. He gives a structure without fully resolving the question of individual immortality that the structure raises, and later readers filled that gap in sharply different ways. Reading the treatise on its own terms, rather than through the lens of how Avicenna or Averroes later resolved the ambiguity, is worth doing at least once.

Read it alongside Al-Farabi’s Attainment of Happiness. The theoretical virtue that treatise names as the foundation of happiness is achieved, on this treatise’s account, precisely by ascending through these stages to the acquired intellect, so the two works interlock directly.

And keep the later reception in mind as a measure of the treatise’s importance. When Aquinas argues, against a widespread Latin Averroist reading of Aristotle, that each individual human being has their own agent intellect rather than sharing one universal intellect with the whole species, he is arguing inside a conceptual framework this short Arabic treatise did more than any other single text to establish.

Questions it raises

• If the Active Intellect is separate from any individual soul, in what sense is the thinking that results from it your own thinking?
• Does the acquired intellect’s conjunction with something universal and eternal secure any kind of personal immortality, or only an impersonal one?
• Is the light analogy a genuine explanation of how thought becomes actual, or a way of naming the problem rather than solving it?
• Al-Farabi separates popular, theological and Aristotelian senses of intellect before analyzing only the last. Does that separation clarify the inquiry or beg the question against the other senses?
• What would it mean for two people to be actually thinking the same intelligible form at once, given how this treatise describes the process?
• How much of this account depends on the specific cosmology of celestial intelligences, and does it survive if that cosmology is abandoned?