81. Life as Being and Self-Motion

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Lecture Notes

Main Topics #

Life and Self-Motion #

• Life belongs manifestly to animals through their capacity to move themselves
• Life is “hidden” in plants; sometimes unclear whether a plant is alive until it revives after being watered
• Life is absent entirely in inanimate bodies (stones, water)
• The defining characteristic of living things is that they move themselves rather than being moved only by external causes

Life as Being vs. Operation #

• Life can be understood in two ways: (1) as the being or existence of a living thing, and (2) as the operations through which a living thing manifests its nature
• Thomas argues that life is primarily the being of a living thing, though it is named from and known through operations
• The distinction matters: we come to know life through external manifestations (motion, growth, sensation, understanding), but these operations signify an internal substantial reality

Motion and Life #

• Motion in general (change of place, change of quality, growth) has only a likeness to life, not life properly
• The connection between motion and life is metaphorical when applied to inanimate things
• Change of place is the most fundamental kind of motion because all other changes presuppose it

Key Arguments #

Objection 1: All Natural Things Are Alive (Because Motion = Life) #

Argument: Aristotle says motion is a certain life. All natural things partake of motion. Nature is defined by motion. Therefore, all natural things are alive.

Response:

• Motion is called “life” only by likeness, not properly
• The motion of inanimate bodies (like stones falling) proceeds from an external mover, not from the thing itself
• When a stone is in its natural place, it is at rest, showing it does not move by its own nature
• Heavy and light bodies move only when displaced from their natural position; plants move by their own living motion according to their natural disposition

Objection 2: Heavy and Light Bodies Move, So They Live #

Argument: Locomotion is more perfect than growth. All natural bodies have some cause of locomotion. Therefore, all natural bodies are alive.

Response:

• Heavy and light bodies are always moved by an outside mover (the generator of their form, or whatever removes the impediment)
• They do not move themselves; thus they lack the essential characteristic of living things
• Plants build themselves up through their own internal principle; stones do not

Objection 3: Living Waters Are Alive (Because They Move) #

Argument: Waters that flow continuously are called “living,” while stagnant waters are called “dead.” Therefore, motion constitutes life.

Response:

• This is a metaphorical use of “life” based on the appearance of self-motion
• Flowing waters move not from themselves but from an external cause (the spring generating them)
• Like heavy and light bodies, their motion comes from outside, not from an intrinsic principle

Objection 4: Life Is an Operation #

Argument: We distinguish living things by operations (using food, sensing, locomotion, understanding). Therefore, life is a certain operation.

Response:

• While we come to know and distinguish living things through their operations, life is not the operation itself
• The name “life” is imposed to signify the substance or being of a living thing, not the operation
• Analogy: “Body” is imposed to signify a kind of substance, though it can also name a species of quantity; similarly, “life” is imposed for the being of a living thing, though it can secondarily name operations
• Because we know things from the outside first, we name things from external properties, then refer the name to the inward nature

Important Definitions #

Vivum (Living Thing) #

• The primary meaning: a substance whose nature it is to move itself or act according to its own operation
• The name is taken from the external property of self-motion but is imposed to signify the internal substance or nature
• Not an accidental part of the being (which would make it a property) but a substantial division (like dividing substance into living and non-living)

Movere Seipsum (To Move Oneself) #

• In the strict sense: motion as the act of what exists in potency (imperfect act)
• In the extended sense: any operation that proceeds from the agent itself, including understanding, willing, and sensing (perfect acts)
• The higher the grade of self-motion, the more perfect the life

Vivere (To Live) #

• For living things, to live is to be (vivere eventibus esse)
• To live = to have the being or existence of a living thing
• Can also mean to exercise the operations proper to that living thing (secondary meaning)

Self-Motion in Perfect Acts #

• Understanding, willing, and sensing are actions that “remain in the agent” (manere in agente) rather than passing into external matter
• These perfect acts are more properly called life because they constitute the being and perfection of the agent itself
• God’s understanding and willing are perfect self-acts that constitute His eternal life

Examples & Illustrations #

The Stone vs. the Leg #

• When you kick a stone and it rolls, you do not say the stone is alive
• If you step on an insect and it shoots across the path, you might say “it’s alive”
• The difference: the stone is moved by an external cause; the insect moves itself

The Plant and Winter #

• A plant’s life can be hidden during severe winter
• When spring comes and the plant blossoms, we realize it was still alive
• This shows that life is not identical to visible operation; it is the underlying being that was present all along

Living vs. Dead Waters #

• Waters that flow continuously from a source are called “living” (living waters)
• Standing waters in cisterns and ponds that do not flow are called “dead”
• This is a metaphorical use: flowing waters appear to move themselves, but the motion comes from the external source

The Early Automobiles #

• When automobiles first appeared, people wondered, “Where is the horse concealed inside?”
• The name “automobile” (self-moving) seemed strange because moving yourself is what a living thing does
• This shows that self-motion was so closely associated with life that the very concept of a self-moving machine was puzzling

Oysters and Sensation #

• Some creatures in the ocean (oysters) seem almost like plants but react when pricked with a pin
• They appear to have sensation but lack the higher senses like sight and hearing
• They lack local motion (movement from place to place), which requires distant sensory perception

Notable Quotes #

“To live belongs manifestly to animals. It is said sometimes that life is hidden in the plants. But life in the animals is manifest.” —Thomas Aquinas (discussed in lecture)

“For the motion of the heavens is in the universe of natural bodies, something like the motion of the heart in the animal.” —Thomas Aquinas, illustrating the likeness of motion to life

“For the name of life is taken from something outside, appearing about the thing, which is that it moves itself, but nevertheless it is not placed upon [imposed to signify] this, but to signify the substance to which it belongs according to its very nature to move itself.” —Thomas Aquinas, on the distinction between naming life and imposing the name

“To live is for living things to be.” —Aristotle (vivere eventibus esse), cited by Thomas

“Nature loves to hide.” —Heraclitus, cited by Berquist to explain why the inner nature of things is not immediately known

Questions Addressed #

Does life belong to all natural things? #

Resolution: No. Life properly belongs only to things that move themselves. All natural things partake of motion, but this motion is either (1) internal self-motion (as in living things) or (2) external motion caused by something else (as in inanimate bodies). Only the former constitutes true life. Motion in general may be called a “likeness” of life metaphorically, but this is not life properly speaking.

Is life an operation or a being? #

Resolution: Life is primarily the being or existence of a living thing (vivum est substantiale), but it is named from and known through operations. The name “life” is imposed to signify the substance of a living thing, not its operations, though it can be used secondarily to refer to operations. We come to know things through external manifestations first, so we name things from what appears outward, then refer that name to the inward substantial nature.

Why is this distinction important? #

• In creatures, there is a real distinction between being and operation
• In God, being and operation are identical (God’s existence is His understanding and willing)
• This explains why God’s life is eternal and unchanging: it is not an operation superadded to His being but is identical with His very existence

How do we know things are alive? #

Answer: We distinguish living things and non-living things by observing self-motion. In animals, this is manifest. In plants, it is hidden but present. In inanimate things, there is no intrinsic principle of self-motion. We recognize a thing as alive when it moves itself; we recognize it as dead when it no longer has any self-motion and is moved only by external causes.