52. Ability and Act: Refuting the Megarian Error

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Lecture Notes

Main Topics #

The Five Senses of Ability #

Berquist distinguishes five meanings of ability (potentia/dunamis):

1. Active ability: The fundamental sense—the power to act upon another or move another
2. Passive ability: The power to be acted upon or moved by another (refers back to active ability)
3. Resistant ability: The capacity to resist corruption or undergo hardship well
4. Ability to act well: The capacity to perform an action excellently
5. Ability to undergo well: The capacity to be acted upon beneficially

All secondary senses refer back to the primary active sense. The ability to be burned refers to fire’s ability to burn; the piano’s playability refers to the pianist’s ability to play.

Natural vs. Rational Abilities #

Natural Abilities:

• Determined by nature to one of two opposites
• Fire necessarily heats (does not cool)
• Found in soulless things and non-rational soul parts
• Limited and fixed in their operations

Rational Abilities:

• Open to contraries or opposites
• The doctor can heal or harm through medical knowledge
• The logician can construct valid or sophistical arguments
• The same knowledge encompasses both opposites
• Found in the rational soul

Critical Point: This distinction does NOT mean reason lacks natural determination. Rather, rational ability = natural ability + capacity for choice among contraries. This is a compositional distinction (like 3 = 2 + 1), not an absolute one (like sweet vs. bitter).

Modern Misunderstanding of the Nature/Reason Distinction #

Modern philosophers (Mill, Sartre) treat the distinction as absolute:

• They claim reason is determined to nothing
• They deny that the will has any natural orientation
• This leads to radical skepticism: “we never really know anything”
• They misunderstand that reason and will CONTAIN natural determination PLUS additional freedom

Berquist shows this stems from custom: accustomed to the experimental method, moderns treat all ideas as hypotheses, never recognizing that they naturally know certain truths (like the axiom of non-contradiction) without testing them.

The Axiom of Non-Contradiction as Naturally Known #

Modern scientists use the axiom of non-contradiction in their experimental method:

• When experimental predictions are contradicted, they reject hypotheses
• They cannot test this axiom without assuming it (self-refuting)
• Yet they claim to treat ALL knowledge as hypothesis
• This reveals they DO naturally know this axiom, even while denying it

The Megarian Error and Its Refutation #

The Megarian Position: “A thing is able to act only when it is actually acting; when not acting, it is not able.”

Examples: “He who is not building is not able to build, but only he who is building, when he is building.”

Four Absurdities Follow:

1. Loss and Acquisition of Arts: A builder would lose the art of building whenever he stops building and instantly reacquire it upon resuming. But arts take considerable time to acquire and lose through forgetfulness or sickness—not instantaneous transitions.

2. Sensible Properties Disappear: Sugar would not be sweet when no one tastes it; birds would not sing when no one hears; nothing would be hot, cold, or sensible at all when unperceived. This forces acceptance of Berkeley’s idealism (“To be is to be perceived”), denying objective properties.

3. Blindness and Death Multiply: A person would become blind whenever not seeing and would die whenever not living. This multiplies miracles throughout the day, making the miraculous commonplace.

4. Elimination of Motion and Becoming: If nothing can be other than it actually is, all change and motion become impossible. The sitting person could never stand up because standing up would require an ability the person lacks (not currently standing). This denies the very possibility of change itself.

Conclusion: The Megarian position denies real potentiality and thus eliminates motion, becoming, and contingency from reality.

Act as Motion: The Most Known But Least Actual #

Aristotle shows that motion is the act most known to us through sensation, yet it is the least actual of all acts:

Why Motion Seems Most Real:

• “Things in motion sooner catch the eye than what not stirs”
• Children want to go where the action is
• Moderns emphasize process, history, and flux (Hegel, Marx, existentialism)
• A philosopher reading a book seems to be “doing something” more than one thinking while looking up from the page

Why Motion Is Actually Least Actual:

• When walking from point A to point B, no part of the motion is ever fully actual
• The past part is no longer actual; the future part is not yet actual
• Only an infinitesimal present moment exists, which is not a real part of motion
• Therefore, motion is perpetually incomplete and never fully realized

This paradox explains the modern philosophical tendency toward denying substance and permanence, treating reality as pure flux and process.

Ability and Act as Fundamental to Being #

When dividing being according to ability and act:

• Being is said of act BEFORE ability (act is more fundamental)
• Ability is said always in reference to act, not vice versa
• This is not equal predication (like “animal” said of dog and cat)
• Act is the primary meaning; ability is secondary

Example: We say “I am sitting,” not “I am standing” (even though able to stand). The actual state takes precedence in our speech and understanding.

Key Arguments #

The Self-Refutation of Modern Determinism/Skepticism #

1. The Experimental Method Assumes Non-Contradiction: Modern scientists predict consequences and reject hypotheses when predictions are contradicted by observation
2. But This Assumes the Axiom: To say “no eclipse occurs” contradicts “an eclipse occurs”—which assumes something cannot both be and not be
3. They Treat the Axiom as Hypothesis: Yet they claim to test all ideas as hypotheses
4. Logical Impossibility: You cannot test whether the axiom of non-contradiction is true or false—testing it already assumes it
5. Revelation of Natural Knowledge: Therefore, they MUST naturally know the axiom, even while denying that anything is naturally known

The Analogy of Euclid’s Sixth Theorem (Proof by Contradiction) #

Berquist illustrates the structure of natural knowledge through geometric proof:

• Given: Two angles of a triangle are equal
• Assume opposite: The sides are not equal
• Derive contradiction: One side is longer; cut off an equal segment; the resulting smaller triangle equals the larger
• Apply axiom: The part cannot equal the whole
• Conclusion: The assumption must be false; the sides must be equal

This shows how we naturally know that the whole is always greater than the part, and use this natural knowledge to judge things we don’t naturally know.

Why Rational Ability Encompasses Contraries #

1. Knowledge is Reflexive: In understanding one contrary, one necessarily understands the other (e.g., blindness is defined through sight)
2. Knowledge is Not Determined: The same medical knowledge enables both healing and harming
3. But Contraries Cannot Occur Simultaneously: A doctor cannot both heal and harm the same patient at the same time
4. Therefore Choice Determines Action: What determines which contrary is actualized must be something additional—the doctor’s will or choice
5. Without This, Rational Ability Would Be Irrational: The ability would simultaneously actualize incompatible acts

The Distinction as Compositional, Not Absolute #

The distinction between natural and rational ability is:

• NOT like sweet vs. bitter (absolutely different; no sweetness in bitter)
• NOT like virtue vs. vice (opposites; one does not contain the other)
• BUT like 2 vs. 3 (3 = 2 + 1; 3 contains 2 plus something more)

Therefore:

• Rational ability contains natural ability plus something more (capacity for choice)
• Reason naturally knows certain truths plus has freedom to think about contraries
• The will naturally wills happiness plus can choose among different goods

Important Definitions #

Ability (potentia/dunamis): A principle or source of change in another thing or in the same thing as other; the capacity to act or be acted upon.

Act (actus): The realization or actualization of ability; the exercise of a capacity; what is actually so, as opposed to what is merely possible.

Natural Ability: An active power determined by nature to produce one specific effect; characteristic of soulless things and non-rational soul parts.

Rational Ability: An active power open to contraries; found in the rational soul; requires an additional determining factor (will, choice, desire) to actualize one contrary rather than another.

Passive Ability (passiva potentia): The capacity to be acted upon or moved by an active ability; always refers back to an active ability in another subject.

Examples & Illustrations #

The Pianist and Piano #

• The pianist has the active ability to play
• The piano has the passive ability (playability) to be played
• These are two distinct abilities in two distinct subjects
• When the pianist pauses, he does not lose the ability (contra Megarians)

The Doctor #

• Medical knowledge enables healing or harming
• The same art encompasses both contraries
• Choice determines which act occurs
• Nazi doctors demonstrate how medical knowledge can be perverted to harm

The Logician/Sophist #

• The same knowledge of logic enables valid or sophistical arguments
• Example sophism: “Happiness is the end of life. The end of life is death. Therefore, happiness is death”
• The logician’s ability encompasses both good and bad use

The Poet/Musician #

• Shakespeare by poetic art can write tragedy or comedy
• Mozart can write happy or sad melodies
• The same rational ability is open to contraries

The Fire and Paper #

• Fire necessarily heats paper (determined to one contrary)
• Fire does not deliberate whether to heat or cool
• Moist paper is not burnable well (passive ability limited by matter)
• Natural ability is fixed and determinate

The Blind Person #

• A person who is not seeing is not blind (can see; has the ability)
• A person who lacks the ability to see is blind (lacks the power)
• This distinguishes lack (privatio) from mere non-functioning

The Pianist Who Pauses #

• When the pianist pauses, he still has the ability to play piano
• The Megarian view would say: “He is not able to play when not playing”
• But the pianist can resume immediately, showing the ability persists
• This contradicts the Megarian position

Notable Quotes #

“Things in motion sooner catch the eye than what not stirs.” — Shakespeare, cited by Berquist on why motion seems most real

“Use almost can change the stamp of nature.” — Shakespeare, on the tremendous force of custom in shaping thought

“To be is to be perceived.” — Berkeley (S-E-S-P-R-C-P), representing the modern denial of objective properties that follows from the Megarian error

“The accident of Mr. Smith have no more need of a substance to exist in than the earth has need of an elephant to rest upon.” — Bertrand Russell, on modern rejection of substance

“It is not hard to see the absurd things that follow upon such opinions.” — Aristotle, introducing the refutation of the Megarian position

Questions Addressed #

How can natural ability and rational ability both exist? #

Answer: Rational ability is NOT opposed to natural ability but includes it. The rational soul is a nature (naturally determined to know truth, will good) PLUS has the capacity to think about contraries. The distinction is compositional: rational ability = natural ability + capacity for choice.

Why do moderns deny natural knowledge? #

Answer: Custom. Accustomed solely to the experimental method, they treat all ideas as hypotheses to be tested. This custom becomes a second nature, leading them to deny anything is naturally known. But their own method self-refutingly assumes natural knowledge (the axiom of non-contradiction).

How can the axiom of non-contradiction not be an hypothesis? #

Answer: To test the axiom by observation, you would need to observe something both being and not being. But the very act of saying “the prediction contradicts the observation” assumes the axiom. Therefore, you cannot test it—you must naturally know it.

What determines which contrary a rational ability will actualize? #

Answer: Something beyond the ability itself—the will, choice, or desire of the agent. Without this determining factor, the rational ability would simultaneously actualize incompatible opposites (impossible).

Why is motion seemingly most real yet actually least actual? #

Answer: Motion catches the senses and dominates modern thought. But motion is perpetually incomplete: its past is no longer actual, its future is not yet actual, and only an infinitesimal present moment exists. Therefore, motion is the least actual of all acts, even though it appears most real to us.

How does understanding ability and act lead to God? #

Answer: Ability is always said in reference to act; act is more fundamental. Following this distinction through all being, one arrives at something that is pure act with no unrealized potential—which is God. This is the foundation of the first way (from motion) to God’s existence.