107. The Agent Intellect and the Necessity of Abstraction

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Lecture Notes

Main Topics #

The Problem: Why Understanding Requires an Active Power #

Understandable forms do not exist actually outside the soul in the way sensible things do. Forms existing in matter are only potentially understandable, not actually understandable. Since nothing is reduced from potency to act except by something already in act, an active intellectual power—the agent intellect—must exist in the soul to make potentially understandable things actually understandable.

The Agent Intellect and Images (Phantasms) #

The agent intellect does not act directly on the possible intellect. Rather, it requires:

• Phantasms (φάντασμα): images or likenesses from sensation and imagination containing particular, material conditions
• Proper disposition of the internal sense powers
• Experience (experientia): a collection of many memories of similar things, formed through the cogitative power or particular reason

The agent intellect abstracts the universal from these singular, material conditions in the phantasms. The content and determinacy of understanding comes from the phantasms; the perfection of judging comes from the agent intellect.

Imagination vs. Understanding: A Critical Distinction #

English philosophers (particularly Locke) confuse the image of a triangle with the understanding of what a triangle is:

• Image: Always singular (isosceles, scalene, or equilateral)
• Understanding: Universal (grasps what is common to all triangles independently of type)

One cannot imagine a triangle that is neither isosceles, scalene, nor equilateral. Yet one understands that the interior angles of any triangle equal two right angles—a universal truth independent of which type of triangle. This distinction shows understanding and imagination are fundamentally different acts.

Third Act vs. Second Act of Thinking and Imagining #

Aristotle distinguishes thinking from imagining by showing:

• One can imagine a terrorist without any reason to think one exists
• One cannot think a terrorist is present without having a reason to think so
• Imagination can be arbitrary; thinking requires rational grounds

Example: One can imagine winning the Massachusetts sweepstake without having bought a ticket, but one cannot rationally think one has won without purchasing a ticket. Imagination does not necessarily involve emotion or judgment; thinking does.

The Agent Intellect as Not a Separated Substance #

Thomas defends the agent intellect as a power of the human soul against the Averroist position that it is a separated substance (like an angel). The analogy of light clarifies this:

• Light is “separated” from the eye (not the act of a bodily organ)
• Yet light is not a separated substance; it emanates from the sun
• Similarly, the agent intellect is “separated” from bodily organs but is a power of the soul, not a separated substance
• Since souls are multiplied according to the multiplication of men, there are many agent intellects

Divine Illumination and the Light of Reason #

The agent intellect participates in God’s illuminating power. James 1:17 states: “Every good giving and every perfect gift is from above, coming down from the Father of lights.” This text explicitly emphasizes that:

• God is called the “Father of lights” (not coincidentally)
• The lights descending from Him include at least three: the light of reason (natural intellect), the light of faith, and the light of glory
• The light of reason—the agent intellect—is a perfect gift and good giving from God
• This light enables us to be “a kind of first fruits of his creatures”

God illuminates as a universal cause through the Word (John 1:9: “the Word enlightens every man”). The human soul participates in this divine light through the agent intellect, which flows from God through the soul’s essence.

Key Arguments #

Objection 3: If Agent and Possible Intellect Suffice, Why Not Always Understand? #

Response: The agent intellect does not contain within itself the likenesses of all sensible things. It requires:

• The presence of phantasms (images from sense and imagination)
• Good disposition of the sense powers
• Exercise and practice in forming images

Berquist’s example: When learning solid geometry, his imagination was not forming the necessary images naturally. He constructed cardboard models and hung them from the kitchen light for months to train his imagination. Only then could his agent intellect work effectively with properly disposed phantasms.

Further, understanding flows from one thing to another—as through terms propositions become known, and through first principles conclusions become known—following the three acts of reason. This discursive process takes time and depends on prior understanding.

Objection 4: How Can the Soul Be Both in Act and in Potency to the Same Thing? #

Response: The soul and phantasms are in opposite states regarding the same perfections:

• The soul: in act regarding immateriality but in potency to determinate forms/likenesses
• The phantasms: in act regarding particular likenesses of species but in potency to immateriality and universality

Therefore, one power of the soul (the agent intellect) can actualize what is in potency in the phantasms without contradiction. The understanding has actual immateriality but lacks the actual determinate forms; the images have the actual likenesses but lack universality and immateriality.

Objection 5: Agent Intellect Comes from God, Not the Soul #

Response: This is not a true objection. Since the soul itself is created by God and powers flow from the soul’s essence, receiving the agent intellect either directly from God or through the soul’s creation by God amounts to the same thing. The soul is immaterial and created by God; nothing prevents the power that abstracts from matter (the agent intellect) from proceeding from the soul’s immaterial essence, just as other powers do.

Important Definitions #

Phantasm (φάντασμα / phantasma) #

An image or sensible likeness retained in the imagination. It contains a particular, material likeness of sensible things. The phantasm is in act regarding the particular likeness but in potency to immateriality and universality.

Agent Intellect (Intellectus Agens) #

The active intellectual power of the soul that makes potentially understandable forms actually understandable by abstracting universal natures from the material and singular conditions in which they exist in phantasms. It is compared by Aristotle to light (φῶς / lux), which illuminates without being a separated substance.

Possible Intellect (Intellectus Possibilis) #

The passive intellectual power of the soul that receives intelligible forms. It is in potency to all understandable things and in act regarding immateriality but in potency to determinate forms.

Experience (Experientia) #

A collection of many memories (retentiones) of the same kind of thing, formed through the cogitative power. It is intermediate between simple memory and universal knowledge. Aristotle compares it to an army forming from fleeing troops: individual soldiers stand, then more stand, until a firm line is established.

Cogitative Power (Vis Cogitativa) / Particular Reason (Ratio Particularis) #

The highest internal sense power that brings together individual phantasms. It functions like reasoning but operates on particulars rather than universals. Through the cogitative power, many similar memories coalesce into experience.

Abstraction (Abstractio) #

The process by which the agent intellect makes universal forms actually intelligible by separating them from material and individual conditions. This does not mean physically removing something from matter but rather actualizing the intelligible aspect that was only potential in the material condition.

Examples & Illustrations #

The Triangle Problem #

When studying geometry, one cannot imagine a triangle that is neither isosceles, scalene, nor equilateral. Yet Euclid proves that the interior angles of any triangle equal two right angles—a universal theorem independent of which type. This shows understanding grasps what imagination cannot: the universal nature common to all triangles.

Solid Geometry and Imagination #

Berquist struggled to form the necessary phantasms (images) for solid geometry. He constructed cardboard models and suspended them from his kitchen light for months to train his imagination to properly form the required complex figures. This illustrates the agent intellect’s dependence on well-disposed phantasms.

Recollection and the Cogitative Power #

When trying to remember what one was doing yesterday at 4 PM, one might not recall directly. But by working backward through memories (“I went to chapel at 2, then came out…”), one reconstructs the memory. This shows how the cogitative power (particular reason) functions almost like reasoning, collecting and ordering individual images.

The Familiar Stranger #

Berquist encountered someone who looked familiar but he could not place. It turned out to be a former student from Anna Maria College. This illustrates how the cogitative power recognizes particulars through experience, though not always successfully.

The Terrorist Imagination #

One can imagine a terrorist without any reason to suppose one exists. But one cannot rationally think a terrorist is present without evidence. Imagination is free from rational constraint; thinking requires grounds.

The Sweepstake Example #

One can imagine winning the Massachusetts sweepstake without having purchased a ticket. But one cannot think one has actually won without having bought a ticket. The intellect is bound by reason; the imagination is not.

Aristotle’s Army Metaphor #

Aristotle compares experience (experientia) to an army forming: troops are fleeing, one soldier stands firm, then another stands, then another—until suddenly there is a firm, standing army. Similarly, individual memories pass through imagination, one becomes fixed, another becomes fixed, until finally experience is established.

Notable Quotes #

“Nothing is reduced from potency to act except by something already in act.” — Thomas Aquinas, defending the necessity of the agent intellect

“The understanding is a certain undergoing… the understanding is a passive power.” — From the response to a prior objection, establishing the possible intellect’s passivity

“Every good giving and every perfect gift is from above, coming down from the Father of lights.” — James 1:17, cited by Berquist as scriptural basis for respecting the three lights: natural reason, faith, and glory

“I can imagine myself winning the Massachusetts sweepstake and getting ten million dollars. I can imagine that. But I can’t think that I won ten million dollars when I haven’t even bought a ticket. I have no reason to think I won ten million when I haven’t even bought a ticket.” — Berquist, illustrating the distinction between imagination and thinking

“There’s really kind of a tricky thing there to see: the role that the images play in giving the determinate likenesses of things, and the immateriality and universality of them that the agent intellect is responsible for.” — Berquist, on the complementary roles of phantasms and the agent intellect

Questions Addressed #

Why Is an Agent Intellect Necessary if We Have a Possible Intellect? #

Answer: Because forms in matter are only potentially understandable, not actually understandable. An active power is required to actualize them. Sensible things exist actually outside the soul (so no active sense is needed), but understandable forms do not. Therefore, the soul must contain an active power to make them actually understandable.

How Does the Agent Intellect Work? #

The agent intellect does not directly illuminate the possible intellect. Rather, it abstracts universal forms from phantasms (images in imagination). This requires proper phantasms and good disposition of the sense powers. The agent intellect makes the content of phantasms (particular likenesses) actually intelligible and universal.

Is the Agent Intellect a Separated Substance? #

Answer: No. It is a power of the human soul, not a separated substance like an angel. Though “separated” from bodily organs (not their act), it exists as a power of the soul, flows from the soul’s essence, and is multiplied according to the multiplication of souls.

Why Can’t We Always Understand Everything If We Have Both Powers? #

Answer: The agent intellect requires the presence of phantasms (images from sensation and imagination) and proper disposition of the internal sense powers. Without experience and trained imagination, the agent intellect cannot act. Further, understanding proceeds discursively—through terms to propositions, through principles to conclusions—requiring time and prior knowledge.

What Is the Relationship Between the Agent Intellect and God’s Illumination? #

Answer: The agent intellect is a participation in divine light. God, the “Father of Lights,” is the universal cause of all illumination. The agent intellect, as a power of the soul, flows from the soul’s immaterial essence (which is created by God) and represents a particular participation in God’s universal illuminating action. This does not make the agent intellect God or a separated substance; rather, it shows that natural reason itself is a divine gift.