15. The Third and Fourth Ways: Necessity and Perfection

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Lecture Notes

Main Topics #

Two Meanings of ‘Able’ (Potentia) #

Berquist distinguishes between:

• Natural Philosophy Usage: Ability as the beginning of motion or change; can be active (fire is able to burn) or passive (paper is burnable)
• Logical/Mathematical Usage: Compatibility of subject and predicate; whether statements are possible without contradiction (e.g., “a triangle is able to be green” vs. “a triangle is able to be a figure”)

The distinction is crucial because “able to be and not to be” in the third way uses the logical sense—compatibility between things that necessarily or contingently belong together.

The Third Way: From Possibility and Necessity #

The Argument Structure:

1. Observable fact: Some things are found to be generated and corrupted; they are “able to be and not to be”
2. Principle: What is possible not to be, at some time is not (grounded in Aristotle’s Physics I)
3. Implication: If all things could possibly not be, then at some point nothing would exist
4. Problem of the Series: One contingent being cannot cause the perpetuity of others because it doesn’t exist forever; all contingent beings together cannot be the cause because they don’t exist simultaneously
5. Conclusion: There must exist something necessary—something that must exist
6. Further Problem: Not all necessary things can have their necessity caused by another (infinite regress impossible)
7. Final Conclusion: There must be something necessary through itself (not having a caused necessity)

Objection Addressed: The objection that contingency could extend infinitely (fathers begetting sons forever) fails because:

• The series of generations itself is not eternal
• Outside the series must be something causing its perpetuity
• This parallels the need for God’s grace to sustain human perseverance

Connection to Grace and Perseverance #

Berquist draws an extended analogy between:

• The impossibility of contingent beings causing eternal continuation
• The impossibility of human will (renewed daily) being the sufficient cause of perseverance to death

Just as contingent beings require something outside the series for perpetuity, the human will requires God’s special assistance for perseverance. This connects to Augustine’s dictum “only perseverance is crowned” and the necessity of praying for perseverance.

Prayer Examples:

• Anima Christi: Imitates the Our Father but adds explicit petitions for perseverance; traditionally attributed to John XXIII
• The Our Father: “Thy kingdom come” implicitly asks for perseverance, as God’s kingdom does not come unless we persevere

The Fourth Way: From Grades of Perfection #

Principle: Things are found to possess qualities (goodness, truth, nobility) in varying degrees. More and less are predicated of diverse things according as they approach something that is most of all such.

The Causality Principle: What is said most of all to be such in some genus is the cause of all things in that genus (e.g., fire, being hottest, causes all hot things).

Key Aristotelian Maxim: Propter quod unum quodque et illud magis (“On account of which each is more so, that is more so”)

• When the same attribute belongs to two things but to one of them because of the other, it belongs more to the cause than to the effect
• Example: If sweet is said of both sugar and coffee, but the coffee is sweet because of the sugar added, then sweetness belongs more truly to sugar
• Application: If good and being belong to effects because of the cause, the cause is more good and more being

The Transcendentals: Good (bonum) and true (verum) are transcendentals—the most universal predicates. Thomas will later discuss six most universal concepts following Avicenna:

1. Being (ens)
2. Thing (res) - what something is
3. One (unum) - undivided in itself
4. Another thing (aliquid) - distinct from other things
5. True (verum) - knowable
6. Good (bonum) - desirable

Conclusion: There must be something most true, most good, most noble, and consequently most being—which is God.

Connection Between Being, Goodness, and Truth #

Following Aristotle’s principle from Metaphysics II: “Things which are most true are most beings.” This establishes that:

• The cause (being most true and most good) is the cause of effects being true and good
• Perfect being, perfect truth, and perfect goodness are identical in God

Key Arguments #

Argument from Contingency #

Necessity of a Necessary Being:

• Not all beings can be contingent (able to be and not to be)
• Contingent beings do not have ability to exist forever
• If all beings were contingent, nothing would exist now
• Therefore, there must be something necessary

Necessity of Necessity-in-Itself:

• Necessary beings can have their necessity caused (like angels—they necessarily are but have a cause of necessity)
• Not all necessary beings can have caused necessity (infinite regress impossible)
• Therefore, there must be something necessary in itself—God

The Principle of Grades and Causality #

Sensible Examples:

• Fireplace: As one approaches fire, things become warmer; fire is hottest and causes warmth in others
• Geometry: Later theorems are less known than earlier ones; premises are more known than conclusions; axioms are most known and cause knowledge of all else
• Health and Medicine: Medicine is good because it leads to health (the end); health is the ultimate good and cause of medicine being good

The Structure:

• If something belongs to a thing through itself, it belongs perfectly (not in diminished way)
• If it belongs in diminished way, it is not “through itself” but through something more perfect
• This requires tracing back to what possesses the perfection through itself

Important Definitions #

Contingent Being (ens contingens): Something that is able to be and not to be; whose existence is not necessary in itself

Necessary Being (ens necessarium): Something that must be; whose non-existence is impossible

Necessity Caused vs. Necessity in Itself: Necessary beings like angels have their necessity caused by another (God); only God’s necessity is uncaused

Potentiality/Potency (potentia): In the logical sense used here, the compatibility or possibility of predicates belonging together without contradiction

Transcendentals (transcendentalia): The most universal predicates that apply to all being—being, thing, one, another, true, good

Perfection (perfectio): An act or quality that is purely positive, like being, goodness, truth, or nobility

Through Itself (per se): Belonging to something as essential to its nature

Through Another (per aliud): Belonging to something because of dependence on another

Examples & Illustrations #

The Fireplace and Warmth #

As you approach a fireplace, things get progressively warmer. The fire itself is warmest and is the cause of other things being warm. This illustrates how what is most of a quality causes that quality in others.

Geometry and Knowledge #

In geometry, premises are more known than conclusions; early theorems are more known than later ones; axioms and postulates are most known. Working backward through any chain of theorems, you must eventually reach axioms, which are the cause of all other geometric knowledge and are most known.

Health and Medicine #

Medicine is good and desirable, but its goodness is derived from health. Health is the end and ultimate good. Therefore, health is “more good” than medicine, and health is the cause of medicine being good at all.

Fathers and Sons (Infinite Series Problem) #

One generation of fathers and sons might extend indefinitely, but the series itself is not eternal. For the series to perpetually generate, something outside the series must sustain it. Similarly, human choice renewed daily cannot be the sufficient cause of perseverance to death; God must sustain perseverance.

Priority and Modern Language #

Berquist notes that contemporary use of “priorities” obscures the original meaning of prior (before). People speak of “getting priorities straight” without recognizing different senses of “before”—temporal, causal, essential, and evaluative.

Notable Quotes #

“Only perseverance is crowned.” — Augustine and Thomas Aquinas

“What is possible not to be, at some time, is not.” — Aristotle, Physics I (cited by Thomas)

“On account of which each is more so, that is more so.” — Aristotle, Metaphysics II (cited as propter quod unum quodque et illud magis)

“Things which are most true are most beings.” — Aristotle, Metaphysics II

“God is altogether simple, and the closer one gets to God, one becomes something simple.” — St. Teresa of Avila (paraphrased by Berquist)

“We have to get back to the simple understanding of Thomas.” — De Connick (cited by Berquist)

Questions Addressed #

How can contingent beings exist if they are not necessary? #

Contingent beings are sustained by something necessary—ultimately by God. Just as a series of contingent generations requires something outside the series for perpetuity, so contingent beings require a necessary being for their existence and continuation.

Can an infinite series of contingent beings explain existence? #

No. An infinite series of contingent beings, however long, would still be contingent. The series itself would be contingent, requiring a cause outside itself. The perpetuity of the series cannot be explained by members within the series.

What is the difference between necessary beings with caused necessity and God? #

Angels and other created necessary beings have their necessity caused by God. Their necessity is not intrinsic but depends on God’s willing them to be. God alone is necessary through himself, without any external cause.

How does the fourth way differ from earlier ways? #

The third way emphasizes being (something must be necessary). The fourth way emphasizes perfection (something must be most perfect). While both conclude God exists, the fourth stresses God’s nature as possessing all perfections supremely.

How does this connect to human perseverance? #

Just as contingent beings cannot cause eternal perpetuity, human will—even renewed daily—cannot cause perseverance to death. Both require a cause outside the series: God’s conservation of being, God’s grace for perseverance. This is why prayer for perseverance is essential, as the Anima Christi prayer explicitly requests.