143. Plato, Aristotle, and the Problem of Understanding Images

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Lecture Notes

Main Topics #

Historical Positions on Knowledge #

Plato’s Position:

• The understanding is immaterial and operates independently of bodily organs
• Knowledge does not come from sensible things acting upon the intellect, but from partaking in separated, immaterial forms (ideas)
• The senses are themselves spiritual powers; they are not changed by sensible things, but the soul uses sensory change to form species internally
• Both intellect and sensation operate by themselves without bodily causation

Pre-Platonic Greeks:

• Denied that the soul has any operation independent of the body
• Sense and reason both work through the body only

Aristotle’s Position (the Mean):

• The intellect differs from sense and has an operation not in the body
• Sensing and imagining are bodily operations, not immaterial
• Only the understanding and willing are not in the body
• This position captures truth from both extremes

Augustine’s View:

• The body does not sense; rather, the soul senses through the body, which acts as a messenger
• The soul forms in itself what is announced externally
• Distinguishes between knowledge of understanding and knowledge of imagination

The Problem of Understanding Material Things #

The Core Issue:

• Material things require matter in their essential nature
• Yet the intellect must understand universals, which are immaterial
• How can the intellect, being immaterial, come to understand when sensible bodies cannot act upon it?

Aristotle’s Solution:

• The agent intellect (intellectus agens) is required—a higher and more noble power than passive reception
• The agent intellect makes phantasms (images) actually intelligible through abstraction
• Sensible things act upon the senses; the agent intellect makes images intelligible; the possible intellect receives the intelligible species
• Sense knowledge is not the whole cause but rather the matter upon which the agent intellect acts

The Role of Images (Phantasms) in Understanding #

Images Are Necessary for Human Understanding:

• Even after acquiring knowledge, the intellect must turn to images to think in act
• When injury to the brain impedes imagination, understanding of particular things is impeded
• Everyone experiences this: when trying to understand something, one forms images; when teaching, we propose examples

Images as Object, Not Organ:

• The proper object of human intellect is the quidditas (what-it-is) of something sensed or imagined
• A material thing’s nature cannot be known completely except as existing in the particular
• Therefore, the intellect must turn to images to contemplate the universal nature existing in the particular
• Images are to the intellect as exterior sensible objects are to sight—they are on the side of the object, not the organ

Illustration: The Light Bulb Example

• In a dark room, striking the light bulb stops seeing
• This does not prove the bulb is the organ of sight (the eye is the organ)
• The bulb is the object providing light; interference with it prevents seeing as object-interference, not organ-interference
• Similarly, brain injury stops thinking by impairing image-formation (the object of thought), not by being the organ of thought

The Problem of Brain Injury and Thought #

Common Confusion:

• Many conclude that because brain injury interferes with thinking, the brain must be the organ of thought
• This reasoning confuses two types of causal connection: organ-causation vs. object-causation

Logical Analysis of the Argument:

• Form 1: “If brain is organ of thought, then brain injury interferes with thinking. Brain injury does interfere. Therefore, brain is organ of thought.” (Affirming the consequent—INVALID form)
• Form 2: “If brain injury interferes with thinking, then brain is organ of thought. Brain injury does interfere. Therefore, brain is organ of thought.” (Valid form but FALSE premise: the if-then statement assumes what must be proven)
• The if-then statement is not necessarily true because interference with object can have the same effect as interference with organ

Why Aristotle Shows Intellect Is Not Bodily:

• The intellect is not a bodily power and cannot be an organ using a bodily organ
• Therefore, bodily things acting upon the brain do not act upon the intellect directly as an organ
• The connection is on the side of the object (images) which the brain helps produce, not on the side of the organ of intellection

Key Arguments #

Against the Necessity of Images (Objection 7) #

1. The Species Argument: Once the intellect has intelligible forms within itself, it should suffice to understand without turning to phantasms

2. The Imagination Independence Argument: Imagination can operate in act even when sensible things are absent; therefore, intellect should operate without images

3. The Bodiless Things Argument: We can understand bodiless things (truth, God, angels) for which there are no images; therefore, images cannot be necessary

For the Necessity of Images (Thomas’s Response) #

Two Signs/Indications:

1. Experience of Impediment: Brain injuries, fatigue, or sleep impair the imagination and thereby impair understanding. This shows that actual use of imagination is required, not just possession of intelligible species

2. Experience of Use: Everyone experiences forming images when trying to understand; we teach others by proposing examples from which they form images

The Proportion Argument:

• The knowing power is proportional to the knowable
• An angel’s intellect (separated from body) has separated substances as its proper object
• The human intellect’s proper object is the quidditas of something in bodily matter
• Because material natures exist only in particulars, and particulars are known by sense and imagination, the intellect must turn to images to know its proper object

Why the Intelligible Species Is Not Sufficient:

• Species conserved in the possible intellect exist habitually, not in act
• To understand in act requires using these species according to what they are—forms of natures existing in particulars
• Without the particular represented in imagination, the universal cannot be contemplated

Important Definitions #

Phantasm (phantasma): An image or representation in imagination; particular and singular; the material object upon which the agent intellect acts to produce intelligible species

Agent Intellect (intellectus agens): The active power of the intellect that makes potentially intelligible things actually intelligible by abstracting from phantasms; described as “light which enlightens every man”

Possible Intellect (intellectus possibilis): The passive power that receives intelligible species and understands in act; conserves species habitually

Intelligible Species (species intelligibilis): The form produced by the agent intellect from phantasms; universal and immaterial; informs the possible intellect making it understand in act

Quidditas/What-it-is: The essential nature of a thing; the proper object of human intellect; universal and intelligible though existing in particulars in reality

Conjunction (conjunctum): The combination of soul and body; the subject of sensitive operations (sensing, imagining) which are not operations of soul alone but of the soul-body composite

Examples & Illustrations #

The Triangle Example #

• To understand what a triangle is, one must form an image of a triangle
• The imagination presents a particular triangle (equilateral, isosceles, or scalene)
• The intellect understands the universal nature—three sides—from that image
• Without the imagined triangle, the universal cannot be contemplated

The Bookmark Color Example #

• To see the color of a bookmark, the bookmark must be present
• Yet the bookmark is not the organ of sight; the eye is
• The color is the object of sight, and removing the object prevents seeing
• Similarly, the imagined dog is the object of understanding what-it-is-to-be-a-dog; removing imagination prevents understanding

The Geometry Construction #

• When studying solid geometry in Euclid, imagination can fail
• Berquist constructed cardboard geometric figures to help his imagination
• This shows that when imagination is insufficient, external aids help, proving imagination’s necessity for understanding

The Accident Testimony Example #

• After an accident, sworn testimony is collected immediately
• Agreements about details are greater immediately than a month later
• This shows images persist from sensation and degrade over time, confirming they are passions of sense

The House Memory Game #

• Looking at a house for a few seconds, then closing eyes to answer questions
• Demonstrating that images formed by sensation in act persist and can be examined
• Shows the activity and nature of phantasms in memory

Gold Mountain Example #

• A composite image of gold and mountain, neither of which one ever sensed together
• Shows imagination combines and separates images into new forms
• Distinguishes between passive reception of sensible impressions and active manipulation of images

Notable Quotes #

“The question of the immortality of the human soul depends upon the answer to another question: Does the human soul have some operation or activity by itself?” — Aristotle, On the Soul (cited by Berquist)

“The soul understands nothing without an image.” — Aristotle, Book III, On the Soul (cited by Thomas)

“The images have themselves to the understanding soul as colors to sight.” — Aristotle, Book III, On the Soul

“It is more divine to give than to receive.” — Aristotle (on why agent intellect is more honorable than possible intellect)

“What a man is is common to all men…What’s common to them doesn’t exist as common to them except in the mind.” — Berquist, paraphrasing Aristotle and Thomas

“The danger is that he may see a part of the truth and through pride or other human weaknesses boast that he has seen the whole.” — Berquist, on Empedocles’s warning about philosophers

Questions Addressed #

Q: Does the fact that brain injury interferes with thinking prove the brain is the organ of thought? #

A: No. The interference is on the side of the object (images), not the organ. Just as taking away a colored object prevents seeing the color without proving the object is the organ of sight, impairing image-formation prevents thinking without proving the brain is the organ of intellect.

Q: Can we understand without turning to images if we already possess intelligible species? #

A: No. Intelligible species exist in the intellect habitually (potentially), not in act. To use them in act requires considering the universal as existing in particulars, which requires imagination.

Q: How can we understand bodiless things like God if images are necessary? #

A: We understand them through negation or relation to sensible things, not through positive understanding of what they are. True vision of God (beatific vision) will not require images.

Q: Is imagination passive or active? #

A: Both. It is first a passion of sense (passive reception of sensible impressions), but then becomes active when the soul divides and combines images to form new compositions not directly sensed.

Q: What is the connection between objects of sense and objects of intellect? #

A: The proper object of intellect is the what-it-is of something sensed or imagined. Therefore, imagination functions similarly to exterior objects in sensation—as the object-side of intellectual knowing, not as the organ-side.