99. The Three Powers of the Vegetative Soul and Their Theological Significance

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Lecture Notes

Main Topics #

The Three Powers of the Vegetative Soul #

Thomas distinguishes three powers:

• Generative Power (virtus generativa): Produces another living thing like itself
• Growing/Augmentative Power (virtus augmentativa): Gives suitable quantity to the living body
• Nutritive/Feeding Power (virtus nutritiva): Conserves the body in being and suitable quantity

These powers operate on a living body united to a soul. The feeding and growing powers have their effect in that in which they are (the organism itself), while the generative power has its effect in another (a different organism), since nothing generates itself.

The Perfection of the Generative Power #

Thomas argues that the generative power is the most perfect and principal of the three because:

• It approaches the dignity of the sensitive soul by extending to another body, not merely one’s own
• The highest of the lowest nature attains that which is lowest in the higher (Dionysian principle)
• The other powers (feeding and growing) serve the generative power
• It belongs to a thing “now perfect” to make another as itself is

Natural Appetite vs. Sensory Desire #

Thomas clarifies the distinction from the preceding article:

• Natural appetite (appetitus naturalis): Inclination following from a thing’s nature, without knowledge (e.g., plant inclining toward sunlight)
• Sensory/animal appetite (appetitus sensitivus): Follows some form apprehended by sense or reason; requires a special power of the soul beyond mere apprehension

Generation in Living vs. Non-Living Things #

A key objection concerns whether generation can be a power of the living soul, since non-living things also generate:

• In inanimate things, generation comes wholly from outside (extrinsic)
• In living things, generation involves a seed or internal principle that is formative of the body
• The seed is small in size but great in power—a principle of philosophy (ἀρχὴ ἡ ἥμισυ παντός: “the beginning is half of all”)
• Because living generation begins from a small seed, the organism must have a power (growing power) to attain suitable quantity

The Role of Moisture and Heat in Life #

Thomas employs Aristotelian natural philosophy:

• The operation of the living principle is completed through heat, which tends to consume moisture
• Restoration of lost humidity requires the nutritive power
• Food is converted into the substance of the body
• The nutritive power is necessary for the acts of both growing and generative powers

Reproduction as Striving for Immortality #

Following Plato’s Symposium and Aristotle:

• The mortal seeks to be like the immortal so far as possible
• Individual mortal organisms cannot be immortal, but their kind achieves a kind of immortality through reproduction
• This explains natural sexual attraction toward the most beautiful—from fairest creatures we desire increase
• Examples from Shakespeare’s Sonnets (e.g., Sonnet 1: “From fairest creatures we desire increase, / That thereby beauty’s rose might never die”)
• Spencer’s Amoretti and Epithalamion: immortalizing the beloved through poetry
• Even plants resist destruction and seek to perpetuate themselves (dandelions as example)

Names and Ultimate Operations #

Aristotle names the soul by its ultimate operation:

• Man has an “understanding soul” (sensus intellectivus) because understanding is his highest act, though he also senses
• The vegetative soul can be called the “reproducing soul” (generativus) because reproduction is its most perfect operation
• This reflects the principle that we name things by what they can ultimately do

Key Arguments #

Against Calling These Powers “Natural” #

Objection: These powers are called “natural” powers, but powers of the soul should transcend mere nature.

Response:

• Nature and soul can be distinguished: nature is determined to one of two opposites; the soul rises above this
• A plant grows in contrary directions (up and down); reason can cause opposite effects (cure or kill)
• These powers are called “natural” because they have effects like nature (giving existence, quantity, conservation)
• However, they exercise these actions in a higher way and act instrumentally through active and passive qualities
• In Aristotle’s chemistry, the soul digests food using properties of fire; in modern science, through isolable chemicals
• These powers are closest to nature while still rising above it

Against Distinguishing Generative Power from Nutritive Power #

Objection 1: Generation is common to both living and non-living things, so it should not be a power of the living soul specifically.

Response: Living generation differs fundamentally:

• Non-living generation comes wholly from outside
• Living generation proceeds from an internal seed that contains a formative principle
• This internal principle necessitates a distinct power (generative power) in living things

Objection 2: Each thing is conserved through that by which it acquires being. Since the generative power gives being, it should also conserve being.

Response:

• The generative power gives existence to another, not to itself
• The feeding power conserves the body both in being and suitable quantity
• The feeding power is ordered to the conservation of the living thing
• Therefore, nutritive and generative powers must be distinguished

Against Distinguishing Growing Power from Generative Power #

Objection: Non-living bodies receive both species (kind) and suitable quantity from a single extrinsic power. Why should the living soul need two powers for these?

Response:

• Living things generate from a seed, necessarily beginning with small quantity
• The organism requires a power by which it can grow to suitable quantity
• Inanimate bodies are generated from matter determined by extrinsic agent, receiving species and quantity simultaneously
• Living things, beginning from seed, must have a distinct power (growing power) to achieve proper size

Important Definitions #

Generative Power (virtus generativa): The power of a living thing to generate another like itself; most perfect of the three vegetative powers because it extends beyond one’s own body to another

Growing/Augmentative Power (virtus augmentativa): The power by which a living body arrives at suitable quantity

Nutritive Power (virtus nutritiva): The power by which food is converted into the substance of the body, conserving it in being and suitable quantity

Natural Appetite (appetitus naturalis): Inclination of each thing to something from its own nature, requiring no knowledge

Sensory/Animal Appetite (appetitus sensitivus/animalis): Desire following from sensible or rational apprehension; requires a special power of the soul distinct from mere perception

Seed (semen): A principle small in size but great in power; contains a formative principle that shapes the body in living generation

Examples & Illustrations #

Natural Appetite vs. Sensory Desire #

• A plant “likes” sunlight: it tends toward sun and flourishes there, but this follows from nature, not knowledge
• A plant “likes” moist soil, but again this is natural inclination without apprehension
• An animal smelling dinner does not merely smell it; it desires to eat it—requiring a power beyond smell alone
• If the soul needed things perceived only for the act of sensing itself, a separate desiring power would not be necessary

Hunger and Thirst #

• The inclination of the nose to smell does not suffice to explain wanting to eat what is smelled
• If one only wanted to smell dinner, the powers of hunger and thirst would be unnecessary

Screw Assembly Analogy #

• When assembling something and trying to fit a screw where it doesn’t belong, we say “it doesn’t want to go there”
• This is a different sense of “wanting” from “I want my dinner” or “I want to know”
• The screw’s resistance reflects its nature, not appetite

The Cat Seeing the Bird #

• The cat sees a bird and desires to eat it
• The cat’s sight and desire move it to pursue the bird
• This exemplifies sensory perception followed by appetite and motion

The Stroke Patient #

• A person who has suffered a stroke and struggles to walk exemplifies how a power (motive power) requires suitable bodily members to execute its command
• When bodily members are removed from their natural disposition through injury, they no longer obey the appetite of the moving soul

Reproduction and Mortality #

• A beautiful man or woman ages and loses beauty; they have a duty to reproduce so that “when they’re old, there’s someone that’s pretty”
• The beautiful child resembles the parent, perpetuating beauty across generations
• Plants like dandelions persistently reproduce despite human attempts at eradication—demonstrating the natural drive for immortality
• The last words of a neighbor: “It’s a losing battle, though”—about weeds returning year after year

Shakespeare’s Sonnets and Spencer’s Poetry #

• Sonnet 1: “From fairest creatures we desire increase, / That thereby beauty’s rose might never die”
• The poet immortalizes the beloved through verse, preserving beauty in words even as the person ages
• Amoretti and Epithalamion: Spencer’s courtship and marriage poetry to Elizabeth, immortalizing both the courtship and the marriage celebration

Spencer Writing on Sand #

• A friend of Spencer writes his beloved’s name in sand by the ocean
• The wave washes it away, but the poet can immortalize her through his verse

Pregnancy and Gender Recognition #

• The old nurse at the hospital could determine the baby’s sex by listening to heartbeat
• Mothers often report that babies behave differently in utero based on sex
• The claim that girls are carried in back, boys in front is a folk observation some women report

Theological Application: The Three Sacraments #

The Principle #

God understands we are animals with reason. Therefore, under the likeness of bodily life, we receive the elements of spiritual life through the sacraments.

Correspondence #

• Generative Power ↔ Baptism: An indelible seal giving spiritual birth (“born again of water and the Holy Spirit”); parallel to physical birth from mother
• Growing Power ↔ Confirmation: Gives spiritual maturity; the kitten becomes a cat, the boy becomes a man; the Church gives the candidate ability to “stand and fight for the Church”
• Nutritive Power ↔ Eucharist: Under the likeness of bread and wine (most commonly used for food), we receive the body and blood of Christ; Christ’s presence gives life

The Living Bread #

In contrast to ordinary material food:

• Material food is not alive; we give life to it through digestion
• The Eucharist is panis vivus (living bread), vitam praestans hominibus (bestowing life upon us)
• Material food: lower nourishes higher (plants nourish animals, animals nourish humans)
• Spiritual food: higher nourishes lower (higher angels are food for lower angels; Scripture and teaching nourish the mind)
• When we eat material food, it becomes part of us; when we receive Christ, we become Him

Nicodemus’s Confusion #

• Christ speaks to Nicodemus about being “born again of water and the Holy Spirit”
• Nicodemus asks how a man can enter his mother’s womb again
• This shows the analogy: physical birth from mother → spiritual birth through baptism; Church as mother

Breaking the Bread #

• Scripture speaks of “breaking bread and distributing it”
• The bread of Scripture must be broken into bite-sized pieces for consumption
• Thomas divides the text for students as a mother bird feeds worms to chicks
• Teaching and commentary distribute spiritual nourishment

Notable Quotes #

“That to which it has being, being is acquired by the living thing, therefore through that same thing the living thing is conserved.”

“The highest of the lowest nature attains to that which is lowest in the higher.” (Dionysian principle governing the relationship between generative and sensitive powers)

“From fairest creatures we desire increase, that thereby beauty’s rose might never die.” (Shakespeare, Sonnet 1)

“It’s a losing battle, though.” (Neighbor on persistent weeds—exemplifying nature’s drive to immortality)

“The beginning is half of all.” (Greek proverb: ἀρχὴ ἡ ἥμισυ παντός—the seed as small in size but great in power)

“It’s true of knowledge and the same knowledge of opposites, huh? You transcend that being determined to one of two opposites, huh?” (On the soul’s transcendence of nature’s determination)

“When we eat material food, it becomes part of us. When we take in Christ, we become Him.” (Student observation on spiritual vs. material reception)

“Panis vivus, vitam praestans hominibus.” (The living bread bestowing life upon us—contrast with non-living material food)

“When it says in Scripture, you know, there’s no one to break the bread and distribute it, huh? Well, the bread of Scripture, so to speak, you have to break it into something that’s bite-sized, you can eat, right? You distribute it, huh?” (On teaching Scripture as spiritual nourishment)

Questions Addressed #

Why Are These Powers Called “Natural” If They Belong to the Soul? #

• These powers are called natural because they operate through the principles of natural action (active and passive qualities like heat and moisture)
• Yet they exercise these operations in a higher way than non-living nature does
• They are the closest to nature while still rising above it through the soul’s form

How Can Generation Be a Power of the Living Soul If Non-Living Things Also Generate? #

• Living generation differs from non-living generation: it proceeds from an internal seed containing a formative principle
• Non-living generation comes wholly from an external agent
• The internal principle in the seed necessitates a distinct generative power in living things

Why Distinguish Growing Power from Generative Power? #

• Living things generate from a seed, beginning with very small quantity
• They require a distinct power (growing power) to achieve suitable mature size
• Non-living things receive both being and quantity simultaneously from an external agent; living things require sequential development

Why Does the Generative Power Approach the Dignity of the Sensitive Soul? #

• The sensitive soul has a more universal object than the nutritive soul (perceiving external bodies, not just one’s own)
• The generative power extends beyond one’s own body to another body
• Both transcend concern with the individual organism alone
• This illustrates the principle that the highest of the lowest nature attains what is lowest in the higher

How Do These Three Powers Relate to the Sacraments? #

• The sacraments communicate grace under sensible signs appropriate to animal/bodily life
• Baptism mirrors generative power (spiritual birth)
• Confirmation mirrors growing power (spiritual maturation)
• Eucharist mirrors nutritive power (spiritual nourishment)
• This application shows how theological mysteries are rooted in natural philosophy

Connections to Broader Themes #

Aristotelian Philosophy #

• The principle that things are named by their ultimate operation
• The distinction between powers (potentiæ) and operations (operationes)
• Natural philosophy’s account of heat, moisture, and material principles

Thomistic Metaphysics #

• The soul as the form of the living body
• Powers as distinct faculties of a unified soul
• The transcendence of the soul over mere material nature

Platonic and Aristotelian Ethics #

• The concept of becoming like God so far as possible
• Reproduction as participation in immortality
• The role of reason in distinguishing human from animal life

Medieval and Renaissance Literature #

• Shakespeare’s emphasis on reproduction and beauty’s preservation
• Spencer’s use of poetry to immortalize the beloved
• Scriptural imagery of nourishment and growth