On the Intellect

Quick Facts

• Author: al-Kindi
• Date: 9th century CE, exact date unknown
• Original context: Abbasid Iraq and the Arabic translation movement
• Main topic: how the human intellect moves from being able to know to actually knowing
• Main labels: Islamic Falsafa, Aristotelianism, Neoplatonism

The Problem

On the Intellect asks a short but hard question: what has to happen for a human soul to understand something universal?

A sense can receive a particular thing. Your eyes see this triangle drawn in ink. Your ears hear this spoken word. But the intellect understands something more general: triangle, number, human being, cause, substance. These are not just one private image or sound. They are forms the mind can use across many cases.

al-Kindi wants to explain that move. The soul has a power to understand, but that power is not always active. A child may be able to learn geometry before actually knowing geometry. An adult may know geometry, stop thinking about it, and then call it back later. The treatise sorts these stages and asks what makes the change possible.

In One Minute

On the Intellect is al-Kindi's brief classification of intellect. It is one of the earliest Arabic philosophical texts to organize Greek debates about intellect into a set of named levels.

Its main claim is that the human intellect passes through different states. First it is potential intellect: the ability to know, like an empty notebook that can receive writing. Then it becomes actual intellect when it is really thinking an intelligible form. Later it becomes acquired intellect when it can return to that form at will.

The hard part is the first transition. How does a merely possible knower become an actual knower? al-Kindi says the human intellect needs contact with an intelligible form that is already actual. He calls this source the first intellect. He does not give a fully worked-out metaphysics of it, so readers should be cautious. But the basic picture is clear: the human mind does not produce universal knowledge from bare sensation by itself.

The Main Argument

al-Kindi begins from an Aristotelian distinction between potentiality and actuality. Potentiality means a real capacity that has not yet been exercised. Actuality means the capacity is now fulfilled. A seed is potentially a tree. A tree is actually a tree. A student is potentially a geometer. A person proving a theorem is actually using geometry.

He applies this distinction to intellect. The human rational soul is not always thinking every truth it can know. It starts with the power to receive intelligible forms. An intelligible form is the knowable structure of a thing, not its private color or sound. For example, when the mind understands "triangle," it is not locked onto one chalk triangle. It grasps what makes any three-sided plane figure a triangle.

The first state is potential intellect. This is the intellect as a capacity. It can understand forms, but it is not yet doing so.

The second state is actual intellect. This is the intellect while it is actually grasping a form. When you understand why the angles of a triangle add up in a certain way, the form is present in your thinking.

The third state is acquired intellect. This is not a different organ or a separate soul. It is the human intellect after it has gained a form so that it can think it again when it chooses. If you learned the proof yesterday and can recall it today, your intellect has acquired that intelligible content.

Then al-Kindi adds a fourth item: the first intellect. This is the intellect that is always actual. It is not merely able to think; it already has the intelligible forms in act. al-Kindi uses it to explain how the human intellect first becomes actual, much as a visible object helps sight become actual seeing. Scholars debate exactly how this first intellect fits into al-Kindi's wider metaphysics. It is safest to say that, in this treatise, it functions as an external source of actual intelligibility.

The result is a compact theory of knowledge. Human knowing is not just the piling up of sense impressions. It is the soul's reception of universal forms, made possible by an always-actual intellect.

Key Ideas With Examples

• Potential intellect: the mind's ability to know before it is knowing. Example: someone who has never studied logic can still learn logic. The power is there, but the forms are not yet active in the mind.
• Actual intellect: the mind while it is actively understanding. Example: while following an argument and seeing why the conclusion follows, the intellect is in act.
• Acquired intellect: knowledge held so it can be used again. Example: after learning multiplication, you do not need to rediscover it from scratch every time. You can return to it.
• Intelligible form: the universal structure the intellect grasps. Example: your senses meet many individual people, but your intellect can understand "human being" as a general kind.
• First intellect: the always-actual source that helps the human intellect become actual. Example: al-Kindi's comparison is not a modern brain mechanism. It is closer to saying that possible understanding needs an already intelligible object to awaken it.
• Soul: for al-Kindi, the rational soul is the part of us that can understand universal truth. It is not reducible to eyesight, hearing, or imagination.
• Sense and intellect: sensation gives particular appearances, while intellect grasps universals. Seeing one written number is not the same as understanding number itself.

Why It Matters

On the Intellect matters because it helped give Arabic philosophy a vocabulary for mind, soul, and knowledge. Later Islamic philosophers would write much fuller theories of intellect, but al-Kindi's treatise is an early marker of the problem: how can a finite human soul come to know universal truths?

It also shows how early Islamic Falsafa worked. al-Kindi is not simply repeating Aristotle. He is reading Aristotle through late antique Greek commentators and through a world shaped by the Arabic translation movement. That is why the treatise feels both Aristotelian and Neoplatonic. It uses Aristotle's act/potential distinction, but it also treats intellect as a higher, immaterial source of intelligibility.

The work is short, but its afterlife is large. al-Farabi, Ibn Sina, and Ibn Rushd all develop more elaborate accounts of potential intellect, actual intellect, acquired intellect, and active or agent intellect. They do not simply copy al-Kindi's meanings. In fact, "acquired intellect" can mean something different in al-Farabi. But al-Kindi helps open the shared problem-space.

Proponents, Critics, and Opponents

al-Kindi's proponents are the philosophers of the early falsafa tradition who thought Greek psychology could be made useful in Arabic intellectual culture. The treatise fits his larger project in On First Philosophy: philosophy is a disciplined search for truth, and Greek learning can serve that search.

Its sources and conversation partners include Aristotle's De Anima and late antique commentators such as Alexander of Aphrodisias and Themistius. These thinkers had already tried to clarify Aristotle's difficult remarks about the intellect that receives forms and the intellect that makes thinking possible.

Later philosophers did not treat al-Kindi as the final word. al-Farabi and Ibn Sina gave more systematic accounts of the active intellect and of how abstraction from experience works. Ibn Rushd later made Aristotle's psychology a major battlefield in both Arabic and Latin philosophy. Critics of falsafa, especially theologians suspicious of Greek metaphysics, could object that theories of separate intellects made knowledge too dependent on philosophical speculation.

Modern readers should also be cautious. On the Intellect is brief and compressed. al-Kindi names levels of intellect, but he does not answer every question a later scholastic reader would ask. The safest reading is to treat the work as an early taxonomy and a focused theory of intellectual actualization, not as a complete philosophy of mind.

Related Pages

• al-Kindi
• On First Philosophy
• Aristotle
• al-Farabi
• Islamic Falsafa
• Aristotelianism
• Neoplatonism