"The Five Ways" | Aquinas's Proofs for the Existence of God | Summa Theologica I, q. 2, a. 3
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- Опубліковано 21 жов 2020
- What are Aquinas's Five Ways? What's the difference between an ontological and a cosmological argument? How does Aquinas answer the problem of evil?
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The first way 15:25
The second way 38:49
The third way 45:46
The fourth way 56:53
The fifth way 1:04:35
Very cool! Can't wait to see more content. Love the work. Becoming one of my favorite channels!
These videos are remarkable! Do you have plans to do any more in the future?
Yes, thank you for the feedback. Video production is on hold for the moment, but I do plan to make more in the future.
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Here is an attempt to symbolize some of the key problems with each of Aquinas' Five Ways using symbolic logic:
First Way (Motion)
1. Everything that is moved is moved by another (premise)
1. There cannot be an infinite regress of movers (premise)
1. ∴ There must be an unmoved mover (from 1 and 2)
Problem:
4\. ◇∃x(~Mx & ~∃yMyx) It is possible that there exists some x that is unmoved and yet there is no y that moves x
In other words, premise 2 is questionable because it is possible for there to be an infinite regress of moved movers, without any unmoved mover.
Second Way (Causation)
1. Everything that is caused is caused by another (premise)
1. There cannot be an infinite regress of causes (premise)
1. ∴ There must be an uncaused cause (from 1 and 2)
Problem:
4. ◇∃x(~Cx & ~∃yCxy) It is possible that there exists some x that is uncaused and yet there is no y that causes x
As with the First Way, premise 2 is doubtful because an infinite causal regress is possible.
Third Way (Contingency)
1. Contingent beings exist (premise)
1. Contingent beings require a necessary being (premise)
1. ∴ A necessary being exists (from 1 and 2)
Problem:
4. ~□∃xNx It is not necessary that a necessary being exists
The move from contingent beings to a necessary being is invalid. The existence of contingency does not necessitate the existence of necessity.
Fourth Way (Gradation)
1. Finite goods exist (premise)
1. Finite goods require a maximum good (premise)
1. ∴ An absolute maximum good exists (from 1 and 2)
Problem:
4. ~□∃x(Mx & ∀y(My → x≥y)) It is not necessary that there exists some x that is maximally good such that x is greater than or equal to any other good y.
An infinite regress of greater and greater finite goods is possible, without any absolute maximum good.
Fifth Way (Teleology)
1. Non-intelligent things act towards ends (premise)
1. Non-intelligent things require an intelligent director (premise)
1. ∴ There exists an intelligent director of things (from 1 and 2)
Problem:
4. ~□∃xDx It is not necessary that there exists some intelligent director x of things.
The move from the apparent functionality of nature to a cosmic intelligent designer is invalid, since there may be naturalistic explanations for biological teleology.
An infinite regress of the type Aquinas is speaking of is logically impossible. It follows from premisses 1 and 2. Such a series would result in no movement, not movement.
I thought “Whatever is in motion was put in motion by another” was actually “whatever is in motion is in motion by another” which I then couldn’t reconcile with Newton’s laws. Like I thought the agent had to be present and currently acting for motion to be according to Aristotle’s physics. Was I reading a bad translation or missing something? This may not be the place for such a technical question. Thanks for the talk anyways good stuff
These are good questions, and a mountain of secondary literature has been written on the topic. A good place to start is the debate between William Wallace, OP, and James Weisheipl, OP. See Weisheipl's book, Nature and Motion in Middle Ages, (Washington DC: CUA Press, 1985), which has several pertinent essays. Wallace's essay "Saint Thomas and the Pull of Gravity" in Science and the Liberal Concept, (West Hartford, CT: St. Joseph College, 1964) is a good essay. He also has an essay "Newtonian Antinomies Against the Prima Via," The Thomist, vol. 19, no. 2 (1956): 151-192. I don't think either author really resolves the problem. But Weisheipl believes that there does not need to be a conjoined mover. Wallace believes there does need to be a conjoined mover.
Now, on the point of translation: “Whatever is in motion was put in motion by another” and “whatever is in motion is in motion by another” mean the same exact thing. Both ways of translating are acceptable. The first way makes the sense clearer to beginners. The second formulation is a bare bones, minimalist translation that is preferable to someone more advanced.
Can you prove that whatever is unmoved mover is omnipotent, omniscient, omnibenevolent, unique, simple, and perfect?
Not demonstratively from natural reason. You can get part of the way there, however. You can show that the unmoved mover is simple with regard to quantitative and essential parts (i.e., doesn't have body parts or matter-form composition). You can also show that the unmoved mover is perfect in itself, though I'm not sure you can show it is infinitely perfect in the way Christianity claims. Aquinas explicitly says omnipotency is an article of faith, not something proved through natural reason.
Is the word "exist" proper? What does "Ex" here mean. And what does "ists" like "status" or "state". Wouldn't this expression mislead? I mean there are young adults who argue against notion of God by speaking about "teacups" and "speghetti monster"? God is "in" and the sound "ex" impresses the mind the notion of being "out". So I heard someone "when scientists finally find God then I'll believe".
With a lot of words, it is important not to conflate the etymology with the words meaning.
"Existere," from which English gets the word "existence," is equivalent to "To be" (Esse) in Latin, except stylistically. "Existentia" was invented as a technical term in philosophy to translate the Greek "hyparchein," which, for Aristotle, signified the belonging of a predicate to a subject. For instance, he would say the sentence "A is B" means "B belongs to [hyparchein] A."
This meaning is very different from the etymology of "hyparchein" and "existere." In Greek, "hyparchein" etymologically means the unintended or subtle principle of some event or change ("hypo" [under] + "arche" [principle/ source/ origin]). In Latin, "existere" etymologically suggests standing out ("ex" [out] + "stare" [to stand]). The etymology of is interesting and suggestive, but it is certainly not a safe guide to the actual significance of the word as used in philosophy.
In any case, in ST I, q. 2, a. 3, Aquinas does not use the word "existere." I use "exist" to translate "est." The actual title of the article is Utrum Deus est [whether God is].
Here is a comprehensive philosophical critique of the arguments for God's existence in Summa Theologica:
First Way (Motion)
- The argument relies on an outdated Aristotelian physics that viewed motion as a transition from potentiality to actuality. Modern physics rejects this framework. Motion can occur without external causes.
- Even if we grant the principle that whatever is moved is moved by another, it does not logically follow that there must be an unmoved mover. There could be an infinite regress of moved movers, each moved by a prior cause. Aquinas gives no justification for rejecting such a series.
- The argument illicitly moves from observable motions to an unobservable first mover. We have no empirical evidence of a first uncaused cause of motion. It is a metaphysical assumption.
- The argument assumes that the first mover must be God. But even if we grant an unmoved mover, it need not have all the properties of God such as perfection, goodness, infinity etc.
Second Way (Causation)
- As with the first way, the argument relies on an outdated Aristotelian view of causation that is no longer accepted in modern science. Causes do not have to temporally precede effects.
- There are credible modern cosmological theories, like eternal inflation, that posit infinite causal regresses. Aquinas gives no good reason to reject such theories out of hand.
- The argument illicitly moves from observable chains of causation to an unobservable first cause. We have no empirical evidence of a first uncaused cause. It is a metaphysical assumption.
- Even granting a first cause, it need not have the properties of God. It could simply be an impersonal necessary being.
Third Way (Contingency)
- The argument relies on an Aristotelian cosmology of necessity and contingency that does not match our modern understanding of the universe.
- The argument illicitly moves from the existence of contingent beings to a necessary being. We have no empirical evidence of any non-contingent entities. It is a metaphysical assumption.
- The argument equivocates between ontological necessity and causal necessity. Something may be necessary causally but still contingent ontologically.
- Even granting a necessary being, it need not be God. It could simply be an impersonal ground of being.
Fourth Way (Gradation)
- The argument relies on an Aristotelian metaphysics of degrees of perfection that is questionable. There are other explanations for degrees besides exemplar causality.
- The move from finite goods to an infinite good is invalid. Infinite regresses are possible, so no maximum is necessarily implied.
- The maximum being inferred need not be God. It could simply be an impersonal absolute. The properties of goodness, knowledge, power are assumed rather than proven.
Fifth Way (Teleology)
- The argument relies on empirically questionable teleological explanations in biology. Most adaptation is explained by natural selection, not intentional design.
- Even granting the analogy of design, at most this proves a designer, not necessarily God. We have no warrant to assign properties like perfection, infinity or creativity to the designer.
- The argument illicitly moves from particular cases of apparent design in nature to a cosmic designer. Local adaptation does not imply cosmic teleology.
In summary, Aquinas' five ways are based on Aristotelian metaphysics, science and logic that is outdated and empirically dubious. They rely on illicit moves from the observable world to unobservable metaphysical assumptions. And even granting their dubious premises, they do not lead specifically to the God of classical theism. At best, they point to an impersonal first cause, necessary being, maximum goodness or intelligent designer. Aquinas' arguments are ingenious products of their time, but they do not provide compelling reasons to believe in God from the perspective of modern philosophy and science.
Well written but I disagree that the dialectic regarding the 5 ways has been resolved-which seems to be what you are claiming.
The interpretations of the 1st way I’ve heard read motion as the actualization of potential. Here it’s argued that even the continued existence of an x from time t to time t+1 is a change reflecting the continuous underlying dependence of x on forces outside of x itself to bring x from t to t+1.
Regarding the 2nd way & causation, there are numerous “grim reaper” type contradictions when you assume an infinite causal series for a finite effect.
Regarding contingency arguments, many would argue if you accept the PSR you’ll need a necessary foundation if you want to avoid brute facts. As to your claim this foundation doesn’t need to be God, well the divine attributes follow from an analysis of the characteristics of such a foundation. But I’d like to set that aside. By my lights, Rejecting the PSR puts both science & reason on shaky ground.
The fourth way has been interpreted as way of presenting the de Ente argument and is about actuality. That existence is held in a per se causal series. So just as the fire transfers heat to objects that don’t retain heat in themselves so too does God grant acts of existence to beings who don’t have it in their nature to bring about or explain their own existence.
The 5th way interpretation I’m most familiar with has to with innate teleology, not exterior imposed teleology. The whole idea of the law like behavior of the natural world supports this view. That down to whatever scientific level you want to go: chemical, biological, physical, you see predictability (not necessarily determinism) & pattern, Not absolute & utter randomness. sub atomic particles, atoms, molecules, cells, biological parts, whole living things, and non living material exhibit their natures, powers, & characteristics in predictable ways-flowing from the type of substance they are. When you strike a match a flame is created not lilacs. That’s teleology.
(Fine tuning arguments are also used to support a more exterior teleological argument. )
And to make a blatant appeal to authority id recommend the works of Pruss, Kerr, koons , and others.
I’m sure my presentation of these interpretations of the 5 ways has flaws, but to act like there’s still not an ongoing dialectic here is inaccurate by my lights.
Cheers
The rejection of an infinite regress is a logical coclusion from premisse 1 and 2. It can not happen.