74. The Soul as Form of the Body: Thomas's Demonstration

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Lecture Notes

Main Topics #

The Problem and Its Context #

• In Aristotle’s time, there was universal agreement on the existence of the soul but disagreement on its nature
• Contemporary usage of the word “soul” often reflects a narrow (spiritual/immortal) understanding, obscuring the broader meaning: that by which living things are alive
• The problem is linguistic and conceptual, not about the reality itself—similar to Molière’s Mr. Jourdan speaking prose without knowing it

The Core Definition #

• The soul is that by which we first live, sense, move, and understand
• This definition is grounded in immediate human experience: we are aware of performing these operations
• The soul is not the body itself but that by which the body has these operations

Aristotle’s Demonstration (Second Figure Syllogism) #

• Major Premise: That by which a being first accomplishes an action is its form
• Minor Premise: The soul is that by which we first live, sense, move, and understand
• Conclusion: The soul is the form of the body
• This argument employs multiple parallel examples: health as the form that makes a body healthy; the shape of a ball as what makes it a ball; the order of letters as what makes them the word “cap”; the spherical form that makes a bowling ball roll
• Key Principle: Form, not matter, accounts for the characteristic operation of a thing

Thomas’s Argument from Experience #

• Man experiences that he himself understands—not that understanding happens to him
• The same man also experiences sensory pain in his body and himself thinking about relief
• Conclusion: The same subject (the unified man) must both sense (bodily operation) and understand (immaterial operation)
• This contradicts pure Platonism (which would separate understanding soul from body) because:
  • If the understanding soul were entirely separate, it would be “understood” rather than understanding
  • The urgency and unity of experience (pain in body + thought about pain) shows the same subject acts in both ways

The Problem of Immaterial Operations #

• Understanding cannot be a bodily operation (Aristotle, De Anima III)
• Yet understanding must be attributed to the same man who has a body
• Solution: The soul is the form of the body (so it is united to matter), but the soul is not entirely immersed in matter, allowing some of its operations to transcend bodily limitations

Refutation of Alternative Explanations #

The Platonist Position (Soul ≠ Form) #

• Claims man is only the understanding soul, not a composite of soul and body
• Refutation: The man who perceives himself to understand also perceives himself to sense, and sensation is intrinsically bodily
• Since the same subject both understands and senses, the understanding principle cannot be entirely separate from the body

The Averroist Position (Separated Intellect) #

• Claims a separated, angelic-like intellect enables our understanding through intelligible forms
• Connection: We imagine; the separated intellect understands what we imagine; thereby we “understand”
• Refutation (via Aristotle’s proportion): Images relate to the intellect as external sensibles relate to sight
  • External colors don’t see; the wall doesn’t see despite having the colors seen by the eye
  • Similarly, images don’t understand; we don’t understand by being understood through our images
• The intelligible form must be actually separated from the particular image for actual understanding to occur
• Thomas’s diagnosis: Averroes was deceived by the fallacy of accident (taking what is accidental to a thing as essential)

The Cartesian Position (Soul as Mover) #

• Claims the understanding soul is united to the body as a mover to the moved
• Refutation (four-fold):
  1. Understanding moves the body only through desire, which itself presupposes understanding—thus understanding cannot be explained by being moved
  2. Understanding is an immanent action (remaining in the agent), not a transient action like building; thus cannot be attributed to Socrates merely because he is moved
  3. If attributed through motion, understanding would be attributed only instrumentally (like the saw to the carpenter), but understanding is not exercised through a bodily instrument
  4. The action of one part cannot be attributed to another part except accidentally; if soul and body were merely mechanically connected, understanding could not be attributed to the whole man

The Argument from Species #

• The proper operation of man (qua man) is to understand—this distinguishes him from all other animals
• Each thing acquires its species through its form (species derives its name from form; difference comes from form)
• Conclusion: The understanding principle is man’s own form

The Doctrine of Non-Immersion #

• Principle: As a form becomes more noble, it dominates matter more and is less immersed in it
• Application to the human soul:
  • The vegetable soul: minimally transcends matter (merely gives life)
  • The sensitive soul: more transcendent (sensation appears almost immaterial—we carry images of many things without physical replicas)
  • The intellectual soul: the noblest form, transcending matter to the greatest extent
• Unique consequence: The human soul has operations in which bodily matter has no participation: understanding and willing
• Crucial distinction: The soul’s essence is to be the form of a body; but the soul’s existence is not entirely absorbed by the body’s existence

Thomas’s Three-Fold Refutation of Incorrect Positions #

1. Repeats Aristotle’s demonstration (form-based argument)
2. Refutes alternative modes of union (showing they fail to account for man’s actual operations)
3. Argues from the nature of human species (understanding as the distinctive human operation)

The Fifth Reply: Soul as Subsistent #

• The human soul is unique in being subsistent: it has existence (esse) by itself, not merely as an accidental property
• This existence is shared with the body but not fully comprehended by the body
• Consequence: When the body dies, the soul remains in its being (explaining immortality)
• This distinguishes the human soul from all other forms:
  • Animal and plant souls have existence only in and through their bodies (no separate existence)
  • The human soul has existence which the body participates in, but incompletely

The Sixth Reply: Soul’s Natural Inclination to Union #

• The soul belongs to the body “by itself” (secundum se), not accidentally
• Analogy: A light body naturally inclines upward; even when separated from its natural place, it retains this inclination
• Similarly, the soul has a natural aptitude and inclination to union with the body even when separated
• Theological implication: This explains why resurrection is reasonable—the soul’s very nature tends toward reunion with body

Key Arguments #

The Argument from Unified Experience #

• Premise 1: “I experience that I understand”
• Premise 2: “I experience that I sense pain in my body and I think about how to relieve it”
• Premise 3: The same subject cannot be purely immaterial (understanding without body) and simultaneously bodily (sensing with body)
• Conclusion: The understanding soul must be united to the body; it cannot be entirely separate

The Argument from Matter and Form #

• That which first causes an operation is the form (not the matter)
• The soul causes the operation of living
• Therefore, the soul is the form of the body
• Supporting principle: Nothing acts except insofar as it is in act; that by which something is in act is that by which it acts

The Argument from the Nobility of Forms #

• More noble forms are less immersed in matter and transcend matter more
• The human soul is the noblest form in the material order
• Therefore, the human soul transcends matter sufficiently to have operations independent of matter
• These operations are understanding and choosing

The Proportion Argument (Aristotle’s) #

• Images relate to intellect as external sensibles relate to sight
• External sensibles don’t perform the act of sight; the wall doesn’t see though it is seen
• Therefore, images don’t perform understanding; we don’t understand merely by being vehicles of understood forms
• Application: Averroes’s explanation fails; there must be another way the soul is united to the body

Important Definitions #

Forma (Form) #

• That by which a thing is what it is (its actual being)
• That by which a thing has its characteristic operations
• Examples: the shape of a ball (by which it rolls), the arrangement of letters C-A-P (by which they form a word), the order of a table (by which wood becomes a table)

Anima (Soul) #

• That by which we first live, sense, move, and understand
• The form of a living body
• Not itself a body, but that by which a body becomes alive and operative

Subsistens (Subsistent) #

• Having existence (esse) by itself, not merely as an accident or form in matter
• The human soul is unique among material forms in being subsistent
• Allows the soul to exist and operate independently of the body (though naturally inclined to union with it)

Immersus in Materia (Immersed in Matter) #

• Completely determined and comprehended by matter
• Having operations only in and through bodily organs
• Animal and plant souls are entirely immersed in matter; the human soul is not

Immanens (Immanent Action) #

• An action that remains in the agent and perfects the agent (e.g., understanding, sensing)
• Distinguished from transient action (building, heating), which passes into another
• Understanding is immanent, so it must be the act of the understanding subject itself

Fallacia Accidentis (Fallacy of Accident) #

• Treating what is accidental to a thing as if it were essential
• Example: Averroes treated the fact that intelligible form inheres in phantasms as if this were essential to understanding itself

Examples & Illustrations #

The Cookie Cutter / Dough #

• Metal cutter has actual tree-shape; dough has only potential to receive it
• Cookie cutter gives the form it possesses to the dough
• Application: Soul gives the form of life to the body

The Word “CAP” #

• Same letters C, A, T appear in other words elsewhere
• They form the word “cap” only through their arrangement (form)
• Application: The body (matter) is the same as other bodies; it becomes a human body through the soul (form)

The Bowling Ball #

• Rolls because of its spherical form, not because of the material (plastic, rubber, etc.)
• Same material in different form would not roll
• Application: Living things act according to their form (soul), not merely their matter

The Table #

• Is a table by its form (shape/structure), not by being wood
• Same wood could be shaped into a chair
• Application: The body is a human body because of the soul, not because of the matter itself

The Body Floating on Water #

• Part in water, part above water
• Application: The human soul is partly in matter (as form of body) and partly above matter (in immaterial operations)
• Further application: St. Thérèse of Lisieux near death—no longer able to breathe in this world, not yet able to breathe in the next

Sensation and Imagination #

• We carry images of many things (cat, dog, man, table) in our head
• Yet our brain is not filled with miniature statues of everything we know
• Even sensation seems to rise above the limitation of matter
• Application: Even animal sensation transcends pure material determination; human intellection transcends it far more

The Virtuous Person’s Judgment #

• Someone with the virtue of chastity rejects certain things as wrong simply by inclination of virtue
• Does not need to reason; the virtue itself is an inclination to judge rightly
• Application: Knowledge and virtue operate through inclination and participation, not external addition

Molière’s Mr. Jourdan #

• Told he has been speaking prose his whole life but never knew it
• Never had to know the name to speak prose or use it correctly
• Application: We all know the soul exists (we experience ourselves living, sensing, understanding); the problem is merely the name and concept, not the reality

Shakespeare on the Soul’s Freedom #

• Beatrice: “as sure that the hero is innocent as I am that I have a soul”
• Hamlet: “Since my dear soul was mistress of her choice, and could have distinguished, her election has sealed thee for itself”
• Application: The soul exercises choice through understanding and distinguishing; choice requires knowledge

Notable Quotes #

“That by which we first live, sense, move, and understand is the form of the body.” — Aristotle’s principle (via Thomas Aquinas)

“The one who is feeling pain in his body is the one who is thinking about what to do about it.” — Berquist, on the unity of the human subject

“It’s me reading and understanding what I’m reading, right? Or not understanding what I’m reading—but it’s the same me.” — Berquist, on the unified human subject in all its operations

“The soul is that by which we first live, sense, move, and understand.” — Definition encapsulating the entire doctrine

“The human soul is the last word in the nobility of forms.” — Thomas Aquinas (referenced in lecture)

“Since my dear soul was mistress of her choice, and could have distinguished, her election has sealed thee for itself.” — Shakespeare, Hamlet, cited on the soul’s capacity for understanding and choice

Questions Addressed #

How can the soul be the form of the body if understanding is not bodily? #

• Resolution: The soul is not entirely immersed in matter. While the soul’s essence is to be the form of the body (ensuring unity with the body), the soul’s existence is not wholly comprehended by the body. Thus it can have operations that transcend bodily limitations.

If Aristotle says the understanding is “separated” from the body, how can it also be the form of a body? #

• Resolution: The understanding is separated in its operation (not exercised through a bodily organ) but not separated in its being (the soul that understands is the form of a body). This is unique to the human soul.

Why does Averroes’s explanation (understanding through separated intellect) fail? #

• Resolution: If our only connection to understanding is that a separated substance understands what we imagine, then we are not understanding—rather, we are being understood. The proportion of Aristotle shows that images do not themselves understand, just as external sensibles do not themselves see.

Why is the Cartesian explanation (soul as mover) inadequate? #

• Resolution: (1) Movement by understanding presupposes understanding, so it cannot explain understanding. (2) Understanding is immanent action, remaining in the agent, not a transitive action. (3) Understanding is not exercised through a bodily instrument. (4) The action of a mover is attributed to the moved only instrumentally, but understanding is attributed essentially to man.

What explains how the same subject both senses (bodily) and understands (immaterial)? #

• Resolution: Both operations belong to the same soul by different modes: sensing requires bodily organs (soul is immersed in body for this); understanding does not require bodily organs (soul transcends body for this). The soul is not entirely immersed in matter.

How can the soul have existence by itself when it is the form of a body? #

• Resolution: The soul is subsistent (has being by itself) but this being is naturally shared with the body. When the body dies, the soul retains its own being because it is subsistent—unlike animal and plant souls which have no being apart from their bodies.

What does it mean that the soul has a “natural inclination” to union with the body? #

• Resolution: Even when separated from the body (after death), the soul’s nature remains ordered to embodied existence. This is analogous to a light body’s natural inclination to move upward; the inclination persists even if the body is held below. This explains why resurrection is not unnatural but restores the soul to its natural state.

Critical Distinctions Established #

Essence vs. Operation #

• By essence: The soul is the form of the body (united to matter)
• By operation: Some powers of the soul (understanding, willing) are not in the body
• This is the resolution to the apparent contradiction

Complete vs. Partial Immersion #

• Some forms are entirely immersed in matter and have all their operations through matter
• The human soul is not entirely immersed; it is partly above matter
• This allows it to be the form of a body while having immaterial operations

Separation in Being vs. Separation in Operation #

• The understanding is “separated” in its operation (not bodily)
• But not separated in its being (the soul that understands is the form of a body)
• This refutes both pure Platonism and pure materialism

Individual Soul vs. Separated Intellect #

• Each man has his own understanding soul (contra Averroes’s monopsychism)
• This is because the soul is the form of this body, individuating it
• Unlike Platonic forms or Averroes’s separated intellect, which cannot be multiplied in the same species