62. The Soul Is Not a Body: Refuting Materialist Theories

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Lecture Notes

Main Topics #

The Fundamental Question: Is the Soul a Body? #

• Thomas Aquinas definitively answers: No
• The soul is not a body but the act (ἐντέλεχεια) or form (μορφή) of a living body
• Living and non-living bodies are composed of identical material elements, yet differ in fundamental ways—the difference lies in form, not matter
• This requires understanding the distinction between form and matter, act and potency

Historical Context: Ancient Philosophers and Materialism #

• Ancient Greek philosophers investigated the soul through two primary operations: motion and knowing
• Inability to transcend imagination led them to posit the soul as a body
• Atomists (Democritus): conceived soul as mobile atoms in constant motion
• Empedocles: believed the knower must materially contain what is known; thought soul composed of earth, air, fire, water
• They confused act with potency, thinking that to move something one must oneself be moved

Key Arguments Against the Soul Being a Body #

The Form vs. Matter Argument #

• When a body dies, the material elements remain unchanged
• Yet the body is no longer alive—proving the difference is not material but formal
• Example: A wooden chair remains wooden whether it is a chair or broken into pieces; its form (shape/arrangement), not its matter (wood), makes it a chair
• Living and non-living bodies differ not in what they are made of but in how the matter is organized
• Therefore, what makes something alive (the soul) cannot itself be a body

The Principle of Life Argument #

• Not every cause of life is the soul; the heart is a cause of life but is not the soul
• The soul is the first cause of life (πρῶτον ἀρχὴ ζωῆς)
• A body cannot be the first cause of life in a body, just as a tool cannot be the primary principle of its own operation
• Every living body is alive through something that actualizes it—this cannot itself be body (matter in potency)

The Unmoved Mover Objection and Response #

Objection: The soul moves the body; but only things that are themselves moved can move other things; therefore the soul must be a body

Response:

• Not every mover must be moved per se; there exist unmoved movers (as Aristotle proved in Physics VIII)
• The soul is moved per accidens (accidentally) when the body moves, not per se (essentially)
• Analogy: An engine pulls wagons; wagons are “moved movers” but an unmoved mover must exist to initiate motion
• If all were moved movers with nothing pulling the first, there would be no motion at all

The Knowledge Objection and Response #

Objection: The knower must materially contain what is known; the soul knows bodies; therefore the soul must be a body

Response:

• The knower need not actually possess the nature of what is known, only the ability to receive it
• Example: The pupil of the eye is not actually colored but able to receive color
• Example: The tongue is not actually sweet but able to taste sweetness
• Ancient philosophers confused act (actual possession) with potency (ability/capacity)

Important Definitions #

Form (μορφή/forma) #

• Not merely shape or external appearance
• The act or actualizing principle of matter
• Can refer to: shape, arrangement, order, ratio (proportio), disposition of matter
• Example: In a Manhattan cocktail, the 2:1 ratio of whiskey to vermouth is the form; the ingredients are the matter
• Example: In the word “cat” vs. “act,” the order of letters is the form; the letters themselves are the matter
• Example: Carbon monoxide (1:1 ratio of carbon to oxygen) vs. carbon dioxide (2:1 ratio)—same elements, different forms

Substantial Form vs. Accidental Form #

• Accidental form (forma accidentalis): exists in another, not subsistent (e.g., health, shape, color)
• Substantial form (forma substantialis): makes something to be what it is fundamentally; gives being to matter
• The soul is a substantial form (made explicit in Article 2)

Act (ἐντέλεχεια/actus) vs. Potency (δυνάμει/potentia) #

• Potency/Ability: the capacity to be or do something
• Act: the realization or actualization of that capacity
• A living body is matter in potency; the soul is the act that makes it actually alive
• Every body that is alive is alive through something that actualizes it

Per Se vs. Per Accidens Motion #

• Per se (ἐξ αὑτοῦ): by itself, essentially
• Per accidens (κατὰ συμβεβηκός): accidentally, incidentally
• The soul moves the body per se (as its essential function) but is moved per accidens (when the body it animates moves)

Examples & Illustrations #

The Wooden Chair #

• Wood is the matter; chair-shape is the form
• A wooden table has identical matter but different form
• The chair is a chair because of its form, not its matter
• Similarly, a living body and corpse have the same matter but differ fundamentally in form (presence/absence of soul)

The Cocktail Analogy (Manhattan) #

• Matter: rye whiskey and sweet vermouth
• Form: the ratio 2:1 (two parts whiskey to one part vermouth)
• The ratio is not a body; it is an arrangement of bodies
• Without proper ratio, the ingredients fail to constitute a Manhattan

Carbon Monoxide vs. Carbon Dioxide #

• Both made from identical material elements (carbon and oxygen)
• CO: 1:1 ratio (one carbon to one oxygen) — toxic, lethal
• CO₂: 2:1 ratio (two oxygen to one carbon) — harmless
• The form (the ratio) makes the difference, not the matter

The Letters: Cat vs. Act #

• Same three letters (C, A, T) arranged differently
• “Cat” vs. “Act” — different words because of different order (form)
• The order is not itself a body; it is an arrangement of bodily elements
• Demonstrates that form is not identical to matter

The Train (Engine and Wagons) #

• The engine is an unmoved mover
• The wagons are moved movers—they move other wagons but are themselves moved by the engine
• If all were moved movers, nothing would initiate motion (like trying to move one giant object with no external mover)
• Therefore, an unmoved mover is necessary
• The soul is like the engine: it moves the body without being moved per se

The Handkerchief Mouse #

• Berquist’s great-aunt wrapped a handkerchief to resemble a mouse
• It appeared to move itself (self-motion)
• This apparent self-motion is what we recognize intuitively as life
• True self-motion (not mere appearance) indicates the presence of a soul

The Eye Receiving Color #

• The pupil is not actually colored but able to receive all colors
• The eye is not sweet, but the tongue receives sweetness
• Similarly, the soul is not composed of material bodies but able to receive likenesses of them immaterially
• The knower receives form without receiving matter

Notable Quotes #

“The soul is the first beginning or first cause of life in those things which among us live.”

“It is manifest that not just any principle of a living operation is a soul. Because then the eye, for example, would be a soul, since it is in some way a cause of vision.”

“The soul is said to be moved per accident because it’s moved when the body, which it is, is moved.” — Berquist, clarifying the relationship between soul and body’s motion

“Using form there, you don’t mean just shape, right? … It could be the disposition of the matter. It could be the ratio of the matter.” — Berquist, expanding the meaning of form beyond common usage

Questions Addressed #

Q: How can the soul move the body if it is not itself in motion? #

A: The soul is an unmoved mover in the strict sense. It moves the body without being moved per se, though it is moved per accidens (accidentally) when the body moves. Not all movers must be moved; Aristotle proved in Physics VIII the necessity of unmoved movers. This principle applies analogously to the soul.

Q: If living and non-living bodies have identical material composition, what makes something alive? #

A: Not the matter but the form (the organizing principle). The soul is this form—the act that actualizes the body’s potential to be alive. When the soul departs, the same material remains but is no longer alive because the form that made it alive is absent.

Q: How can the immaterial soul know material things? #

A: The knower need not materially possess what is known. The soul has the ability to receive likenesses of things in an immaterial way—it receives form without receiving matter. The eye receives color immaterially (not by becoming colored); the tongue tastes sweetness without becoming sweet.

Q: Why did ancient philosophers wrongly conclude the soul is a body? #

A: They could not transcend imagination. Since imagination always involves the continuous (length, width, depth—characteristics of bodies), they could not conceive of anything non-bodily. They also confused act with potency, thinking that to move something one must oneself be moved, leading them to posit the soul as a mobile body (like atoms).