21. The Nutritive Soul and Generation in Living Things

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Lecture Notes

Main Topics #

The Nutritive Soul as First and Most Common Power #

• The nutritive (feeding) soul is first in the order of being among all life principles
• Present in all living things: plants, animals, and humans
• Cannot be absent in mortal living things, though other powers may be absent without it
• Three operations flow from the nutritive soul:
  • Feeding/Nutrition - preservation of the individual substance
  • Growth - quantitative increase of the living body
  • Reproduction/Generation - production of another like itself

The Soul as Cause in Three Ways (Not Four) #

Aristotle identifies the soul as a cause in three of the four classical causes:

1. Form (Substance) - The soul is the substantial form of the living body

   • Through the soul, the body is alive and has the being of a living thing
   • The form is that through which something has being
   • Examples: geometry is the form of the mind of a geometer; health is the form by which one is healthy

2. Mover (Efficient Cause) - The soul is the principle from which motion originates

   • “Whence is motion itself”
   • Living things move themselves; what is in act can move what is in potency

3. End (Final Cause) - The soul is that for the sake of which the body exists

   • Just as the mind acts for the sake of something, so does nature
   • The form is the end of generation; generation aims at form
   • Example: Michelangelo chipping away marble aims at a certain form in the matter

NOT Material Cause: The soul cannot be a material cause because:

• Matter is essentially passive potentiality
• The soul is act, not potentiality
• Only what is in act can cause; only actuality gives being to potency

Why Generation is the Most Natural Operation #

Generation (producing another like itself) is the most natural work for complete, mature living things:

• Common to all actual things: Even non-living fire generates fire and spreads itself
• The mortal striving to be immortal: Since individual creatures cannot persist forever, they perpetuate their kind and thereby strive to be like God (immortal and eternal) so far as possible
• Natural without consciousness: All things have this appetite/desire naturally, even plants that do not know they’re trying to be like God
• The good is what all desire: Everything seeks its own good; ultimately all seek to be like God, the universal good
• The form as end: Reproduction aims at perpetuating the form/species, not just the individual

Generation vs. Feeding and Growth #

• Feeding: Uses food to preserve the substance of the individual (“I feed myself to remain myself”)
• Growing: Uses food to increase quantity (adding matter to the body)
• Reproduction: Distinguished from both; sometimes understood as the use of excess food beyond what is needed for maintenance and growth

The Immortality of the Soul and Generation of the Human Soul #

• The human soul does not come from the parents (following Aristotle’s Generation of Animals)
• The soul is not dependent on matter; therefore it cannot be produced by transformation of matter
• Parents provide only a suitable body to receive the soul; the soul itself is not brought into existence through bodily generation
• This is why Aristotle saw both the immortality of the soul and its immateriality

Key Arguments #

Refutation of Empedocles’ Materialist Error #

The Problem: Empedocles claimed that plants grow upward because of fire (naturally rising) and downward because of earth (naturally falling)—reducing life to blind physical forces.

Aristotle’s Response:

• This ignores the unity of the living thing as a single nature
• The plant’s roots (reaching downward) function like the animal’s head (reaching upward)—both are organs of nutrition, properly ordered to the soul’s form
• Up and down are relative to the organism’s nature, not absolute directions
• The soul, not blind mechanical forces, maintains the contrary elements in unity

Fire Cannot Explain Living Growth #

Difference between fire and life:

• Fire: Grows without limit (as long as fuel exists); grows in random directions wherever fuel is present
• Living things: Grow to a definite limit (species form); grow in an ordered shape according to the organism’s nature

Example: A mature oak tree has thousands of leaves, all roughly the same characteristic shape. This coordinated order cannot be explained by blind chemical processes or by the action of fire. The soul’s form accounts for this organized development.

Conclusion: Fire may be an instrument the soul uses, but it is not the principal cause of life.

The Soul as End of the Natural World #

• The human soul appears to be the end of the whole natural world
• Hierarchical ordering:
  • Plants use non-living elements (water, soil, elements) to build their bodies
  • Animals use plants for food
  • Humans use both animals and plants naturally for their needs
• This suggests a greater mind directing nature toward the understanding soul
• When understanding souls (and ultimately angels) can attain God Himself through understanding and love, we see nature directed toward union with God

Important Definitions #

The Nutritive Soul (ψυχή θρεπτική / anima nutritiva) #

• The power by which living things are alive with the life of nutrition, growth, and reproduction
• First in the sense that it cannot be absent in mortal living things; other powers require it but it does not require them
• Common to all living things: what all share in the most basic way
• Most universal principle of the being of living things

Generation (γένεσις / generatio) #

• The production of another individual like the parent
• Distinguished from feeding and growth, which preserve and increase the individual
• The most natural operation of complete, mature living things
• A form of striving to be immortal like God through perpetuating the species

Food (τροφή / alimentum) #

• That which is taken in by a living thing to preserve its substance and enable growth and reproduction
• The object of the nutritive power
• Characterized by being:
  • Contrary/unlike before digestion (undigested food is unlike the living body)
  • Like after digestion (becomes part of the living body)

Form (εἶδος / forma) and Substance (οὐσία / substantia) #

• The soul is the substantial form of the living body
• Form = the shape, order, and principle of being in matter
• Substance (in the sense of form) = what makes a thing what it is; the definition of being
• Form is prior in causality: it is for the sake of which matter is prepared

Examples & Illustrations #

The Oak Tree’s Coordinated Growth #

• An oak tree displays thousands of leaves, all of roughly the same characteristic shape
• This remarkable order and coordination cannot be explained by blind chemical processes alone
• The soul’s form accounts for this organized, determinate growth pattern

Fire Jumping Across Roads #

• During large forest fires in Colorado and California, fire sometimes becomes so hot it jumps across roads and ignites new areas
• This illustrates the difference between fire’s growth and living growth
• Fire grows without limit and in random directions wherever fuel exists; living things grow to definite limits in ordered shapes

The Candle Flame Demonstration #

• If you extinguish a candle and hold a match above the smoking wick, the flame will jump down from the match to the candle
• The heat from the match causes the smoke/vapor to ignite
• Illustrates how fire propagates through heat transfer (unlike the ordered growth of living things)

Insects with One-Day Lifespans #

• Some insects (like mayflies) have lifespans of only one day
• Yet they go through their entire cycle—feeding, growth, reproduction—in that single day
• Shows that the operations of the nutritive soul are accomplished even in very brief lives

The Farmer’s Wagon: Hierarchical Ordering of Arts #

• Berquist’s father’s company manufactured farm wagons (“Grain King” wagons)
• Three arts correspond to three principles:
  • Art of using (farmer) → corresponds to use (the end)
  • Art of forming (wagon maker) → corresponds to form (the end of matter)
  • Art of preparing materials (steel producer) → corresponds to matter (for the sake of form)
• Hierarchical command:
  • The art of using commands the art of forming (end commands form)
  • The art of forming commands the art of preparing materials (form commands matter)
• This concrete example manifests how form is the end of matter: matter is prepared for the sake of form
• The farmer’s use of the wagon corrects the wagon maker’s design; the wagon maker’s design determines the steel producer’s work

Notable Quotes #

“The unity of soul and body is so profound that one has to consider the soul to be the form of the body.” — Catechism of the Catholic Church, 365

“For the most natural of the works for living things, which are complete… is making another like themselves.” — Aristotle, De Anima II.4 (as cited by Thomas Aquinas)

“For all things have an appetite for this [immortality], and do whatever they do according to nature for the sake of this.” — Aristotle, De Anima II.4

“From fairest creatures we desire increase, that thereby beauty’s rose might never die.” — William Shakespeare, Sonnet 1 (illustrating the desire to perpetuate beauty through reproduction)

“The stability of the living organism doesn’t make much sense from the point of view of physical principles alone.” — Werner Heisenberg, Gifford Lectures

Questions Addressed #

Why is the nutritive soul called the “first” soul? #

• First in the order of being: It cannot be absent in mortal living things; all other powers require it, but it does not require them
• First in time/generation: In the development of an organism (from fertilized egg), growth (nutrition) appears first, then sensation, then reason
• First in commonality: All living things have it; not all have sensation; not all have reason
• Note: The understanding soul is “first” in a different sense—as the ultimate end and most perfect form of life

Why does the soul have three causes but not four? #

• Matter is essentially passive potentiality; the soul is act (actuality)
• Only actuality can cause: What is in act moves what is in potency; only what is actual gives being
• Form, mover, and end are all based on actuality; matter is based on potentiality
• Therefore, the soul cannot be a material cause, though it is form, mover, and end

How is food both contrary and like what is fed? #

• Before digestion: Food is undigested matter, unlike the living body—seemingly contrary
• After digestion: Food becomes assimilated into the living body, becoming like it
• Resolution: Both ancient philosophers were partially correct; the distinction lies in whether we consider food before or after digestion
• Parallel to knowledge: A new idea initially seems foreign (unlike our existing thoughts); once understood and assimilated, it becomes our own

Why does all life naturally desire to be like God? #

• The desire for immortality: Individual mortal creatures cannot exist forever individually, so they perpetuate themselves through generation
• Perpetuation as quasi-immortality: By making another like itself, the mortal thing strives to be immortal “so far as possible”
• The drive toward form/perfection: When nature forms things and perfects them, it strives toward God, who is universally perfect
• The good as what all desire: Everything naturally seeks its own good; ultimately, all seek to be like God (the universal good)
• Universal natural appetite: This appetite is natural in all things—plants, animals, humans—even though only rational creatures consciously understand it

How does sexual attraction relate to the desire for immortality? #

• Beauty as object of attraction: The beautiful pleases when seen; we naturally enjoy how beautiful things look
• The deeper reason for sexual attraction: Beyond visual pleasure, we are naturally drawn to reproduce with the beautiful in order to perpetuate beauty (Plato’s insight from the Symposium)
• From bodily to spiritual beauty: Plato shows that this desire naturally ascends from perpetuating beauty of the body to perpetuating beauty of the soul (virtue, knowledge)
• The teacher’s transmission of knowledge: Just as a man who plays violin wants to teach others violin so the art persists in history, teachers desire to pass on their knowledge to students

Why can’t we use sexual organs however we wish? #

• Organs ordered to a greater good: Sexual organs are made for reproduction, which is ordered to the common good of the species
• Beyond individual freedom: We are not free to interfere with organs ordered to goods greater than ourselves
• Contrast with hands: We can walk on our hands (contrary to their purpose) without much wrong, because hands are not ordered to so great a good
• The comparison to truth: Just as truth is the common good of the universe and we’re not free to think whatever we want (must seek truth), reproduction is ordered to the common good of the species