# Thomas Aquinas: Logical Flaws? **URL:** \ **Category:** Great Debates\ **Created:** [February 12, 2016, 5:58pm UTC](https://boards.straightdope.com/t/thomas-aquinas-logical-flaws/745954 "2016-02-12T17:58:45Z")\ **Posts on this page:** 20\ **Page:** 2
**Author:** ![leahcim](https://avatars.discourse-cdn.com/v4/letter/l/b4bc9f/32.png) [@leahcim](https://boards.straightdope.com/u/leahcim)\ **Post date:** [February 12, 2016, 9:01pm UTC](https://boards.straightdope.com/t/thomas-aquinas-logical-flaws/745954/21 "2016-02-12T21:01:31Z")
> [@Charlie\_Thomas](#): > > There has to be a cause for all that exists. God does not have a cause. Therefore by your premise, God does not exist. QED. ---
**Author:** ![Thudlow\_Boink](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/thudlow_boink/32/320_2.png) [@Thudlow\_Boink](https://boards.straightdope.com/u/Thudlow_Boink)\ **Post date:** [February 12, 2016, 9:03pm UTC](https://boards.straightdope.com/t/thomas-aquinas-logical-flaws/745954/22 "2016-02-12T21:03:02Z")
> [@MrDibble](#): > > Really? How did he define God. _Not_ prove such a thing exists, mind you, just how did he define the concept he was setting out to prove. I think this is Aquinas’s answer (though I’m not sure I understand all the terminology): [QUOTE=St. Thomas Aquinas] When the existence of a cause is demonstrated from an effect, this effect takes the place of the definition of the cause in proof of the cause’s existence. This is especially the case in regard to God, because, in order to prove the existence of anything, it is necessary to accept as a middle term the meaning of the word, and not its essence, for the question of its essence follows on the question of its existence. Now the names given to God are derived from His effects; consequently, in demonstrating the existence of God from His effects, we may take for the middle term the meaning of the word “God”. [/QUOTE] (I’m quoting from the text of the _Summa Theologica_ I found [here](http://www.newadvent.org/summa/1002.htm).) ---
**Author:** ![Czarcasm](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/czarcasm/32/4050_2.png) [@Czarcasm](https://boards.straightdope.com/u/Czarcasm)\ **Post date:** [February 12, 2016, 9:05pm UTC](https://boards.straightdope.com/t/thomas-aquinas-logical-flaws/745954/23 "2016-02-12T21:05:55Z")
Is it possible to boil that down and _not_ make it sound like circular logic? ---
**Author:** ![Lobohan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lobohan/32/79_2.png) [@Lobohan](https://boards.straightdope.com/u/Lobohan)\ **Post date:** [February 12, 2016, 9:10pm UTC](https://boards.straightdope.com/t/thomas-aquinas-logical-flaws/745954/24 "2016-02-12T21:10:09Z")
> [@Charlie\_Thomas](#): > > He proved it in the Five Proofs: > > [ol] > [li]The Unmoved Mover.[/li][li]First Cause[/li][li]Argument From Contingency[/li][li]Argument From Degree[/li][li]Teleological Argument[/li][/ol] > > Now, one by one. > > The Unmoved Mover goes like this: Some things are in motion. Things can’t move themselves. An infinite chain of movers is impossible. Therefore, there must be an unmoved mover who moves all things. This is what we understand to be God. What moved to create God? Why is there only one God? Why is that God the one Aquinas believes in, and not, Larry, the God of Anal Sex? > [@](#): > > The First Cause: Kinda the same thing, but with causation. All things have a cause. Infinite chain of causes? (imitate “wrong” buzzer from “Family Feud”) Can’t happen. Therefore, there must be a chain of causes that is the cause of all causes. This cause is understood as God. What created God? Saying that there must be a first cause, and then saying that God doesn’t need one is goofy. > [@](#): > > Contingency Argument: Things in the universe either exist or don’t. The things that exist are either contingent or they aren’t. It is impossible for everything in the universe to be contingent, otherwise we end up with a time where nothing existed, and nothing could bring forth existence. This is obviously false because we know we exist. Therefore, there must be a necessary being to bring forth existence. You guessed it: God, or who we understand to be God. The thing necessary to bring fort existence needn’t be an intelligent spirit. It might be the dumb, unthinking laws of the universe. > [@](#): > > Degree Argument: Different kinds of perfection may be found in varying degrees across the universe. These degrees factor in a sort of ultimate standard of perfection. Perfection, therefore, must have a pinnacle. One guess what this pinnacle is. There is no need for a most perfect something. And a most perfect something, if it existed, needn’t be an intelligent spirit. > [@](#): > > And, finally, the Teleological Argument: All natural bodies follow laws of conduct. Some of these are unintelligent (but others not). Laws of conduct are characteristic of intelligence. Therefore, there exists an intelligent being that created these laws. One guess… Water obeys laws when it runs down a mountain into a lake. There is no intelligence at work there. > [@](#): > > Now, this makes sense based on what we have learned since Aquinas’ day. We know for a fact that there was indeed a beginning for the universe. There are indeed bodies that follow laws of conduct. (Think about animals in the forests and the jungles, or, for something more inanimate, rock formations and their erosion.) Can a rock formation move itself? Of course not! Can we move ourselves? Of course not. We require muscle and bone and a functioning brain in order to do so. There are things that don’t exist or do exist. “Cognito ergo sum,” to borrow from Rene Descartes. Therefore, it stands to reason that there must be a First Cause, otherwise existence itself cannot exist. There is nothing whatsoever you’ve said that is in the slightest a strong argument for the existence of any God, much less the psychopath with impulse control issues that is depicted in the Bible. ---
**Author:** ![crowmanyclouds](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/crowmanyclouds/32/19884_2.png) [@crowmanyclouds](https://boards.straightdope.com/u/crowmanyclouds)\ **Post date:** [February 12, 2016, 9:26pm UTC](https://boards.straightdope.com/t/thomas-aquinas-logical-flaws/745954/25 "2016-02-12T21:26:22Z")
> [@Charlie\_Thomas](#): > > There has to be a cause for all that exists. > > > [@leahcim](#): > > > > God does not have a cause. Therefore by your premise, God does not exist. QED. [William Lane Craig] That which [DEL][COLOR=“Black”]exists[/DEL][/COLOR] begins to exist must have a cause! [/William Lane Craig] > [@Czarcasm](#): > > Is it possible to boil that down and _not_ make it sound like circular logic? [Sye Ten Bruggencate] My logic is _virtuously circular_, your logic is is _viciously circular_, because . . . God told me! [/Sye Ten Bruggencate] CMC fnord! ---
**Author:** ![Charlie\_Thomas](https://avatars.discourse-cdn.com/v4/letter/c/77aa72/32.png) [@Charlie\_Thomas](https://boards.straightdope.com/u/Charlie_Thomas)\ **Post date:** [February 12, 2016, 10:34pm UTC](https://boards.straightdope.com/t/thomas-aquinas-logical-flaws/745954/26 "2016-02-12T22:34:54Z")
> [@Lobohan](#): > > What moved to create God? Why is there only one God? Why is that God the one Aquinas believes in, and not, Larry, the God of Anal Sex? > > What created God? Saying that there must be a first cause, and then saying that God doesn’t need one is goofy. > > The thing necessary to bring fort existence needn’t be an intelligent spirit. It might be the dumb, unthinking laws of the universe. > > There is no need for a most perfect something. And a most perfect something, if it existed, needn’t be an intelligent spirit. > > Water obeys laws when it runs down a mountain into a lake. There is no intelligence at work there. > > There is nothing whatsoever you’ve said that is in the slightest a strong argument for the existence of any God, much less the psychopath with impulse control issues that is depicted in the Bible. Well, the laws of the universe had to have a cause in order to exist, otherwise, they could not, and we’d be floating away in space right now. They exist because they have a cause. Remember Newton’s constant? 6.7 times 10^-23? You’re telling me that such a precise number as the universal gravitational constant just popped up outta nowhere? God has always been. Remember that Futurama episode where Bender was God to a tiny race of aliens and then ran into the Big Man Himself? Water and wind erodes rock formations because all things obey a natural law of conduct as Aquinas said. I never said there was an intelligence at work there. There still has to be a Prime Mover, otherwise nothing moves and nothing exists. At the very beginning of all existence, there had to be a Creator. ---
**Author:** ![Little\_Nemo](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/little_nemo/32/3120_2.png) [@Little\_Nemo](https://boards.straightdope.com/u/Little_Nemo)\ **Post date:** [February 12, 2016, 10:35pm UTC](https://boards.straightdope.com/t/thomas-aquinas-logical-flaws/745954/27 "2016-02-12T22:35:00Z")
> [@Charlie\_Thomas](#): > > The Unmoved Mover goes like this: Some things are in motion. Things can’t move themselves. An infinite chain of movers is impossible. Therefore, there must be an unmoved mover who moves all things. This is what we understand to be God. > > The First Cause: Kinda the same thing, but with causation. All things have a cause. Infinite chain of causes? (imitate “wrong” buzzer from “Family Feud”) Can’t happen. Therefore, there must be a chain of causes that is the cause of all causes. This cause is understood as God. I’d say these these arguments illustrate what’s wrong with Aquinas. He follows a ling of reasoning until the point where he reaches a paradox and then he declares that God lies just beyond that paradox. The two arguments you cite start with the premises that everything in motion must have something that set it in motion and anything that exists must have a cause that made it exist. After juggling with some supposed logic, Aquinas concludes that God is the thing which is in motion that nothing set in motion and is the thing that exists without anything causing it to exist. But wait…if you go back to the premises these arguments were built on, they were that nothing can exist with these attributes. Therefore if God must have these attributes in order to be God and nothing can exist with these attributes, then God cannot logically exist. The alternative is that the premises were incorrect. But if that’s the case then you can’t use these premises as the foundation of a logical line of deduction. ---
**Author:** ![The\_Other\_Waldo\_Pepper](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/the_other_waldo_pepper/32/12370_2.png) [@The\_Other\_Waldo\_Pepper](https://boards.straightdope.com/u/The_Other_Waldo_Pepper)\ **Post date:** [February 12, 2016, 10:42pm UTC](https://boards.straightdope.com/t/thomas-aquinas-logical-flaws/745954/28 "2016-02-12T22:42:10Z")
> [@Charlie\_Thomas](#): > > God has always been. Remember that Futurama episode where Bender was God to a tiny race of aliens and then ran into the Big Man Himself? > > Water and wind erodes rock formations because all things obey a natural law of conduct as Aquinas said. I never said there was an intelligence at work there. > > There still has to be a Prime Mover, otherwise nothing moves and nothing exists. At the very beginning of all existence, there had to be a Creator. You believe there is a god “who has always been.” Do you believe there could be _other_ entities who’ve always been? Dozens? Hundreds? You believe there had to be an unmoved mover, an uncreated creator. Do you believe there could have been ten of them? Maybe twenty? Thousands? Millions? ---
**Author:** ![Czarcasm](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/czarcasm/32/4050_2.png) [@Czarcasm](https://boards.straightdope.com/u/Czarcasm)\ **Post date:** [February 12, 2016, 10:45pm UTC](https://boards.straightdope.com/t/thomas-aquinas-logical-flaws/745954/29 "2016-02-12T22:45:00Z")
In other words, how does the argument lead to _your_ god, and your god _only_? ---
**Author:** ![The\_Hamster\_King](https://avatars.discourse-cdn.com/v4/letter/t/8edcca/32.png) [@The\_Hamster\_King](https://boards.straightdope.com/u/The_Hamster_King)\ **Post date:** [February 12, 2016, 10:45pm UTC](https://boards.straightdope.com/t/thomas-aquinas-logical-flaws/745954/30 "2016-02-12T22:45:31Z")
> [@Charlie\_Thomas](#): > > You’re telling me that such a precise number as the universal gravitational constant just popped up outta nowhere? Sure. If things can just pop into existence it’s more likely a single number would pop into existence than a complicated intelligent being. Imagining God just popping into existence is like imagining a very complicated pocket watch just spontaneously assembling itself. ---
**Author:** ![crowmanyclouds](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/crowmanyclouds/32/19884_2.png) [@crowmanyclouds](https://boards.straightdope.com/u/crowmanyclouds)\ **Post date:** [February 12, 2016, 10:51pm UTC](https://boards.straightdope.com/t/thomas-aquinas-logical-flaws/745954/31 "2016-02-12T22:51:40Z")
> [@Charlie\_Thomas](#): > > Well, the laws of the universe had to have a cause in order to exist {…} No, they don’t. The “laws of the universe” simply describe what we observe. They are descriptive not proscriptive. CMC fnord! ---
**Author:** ![Thudlow\_Boink](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/thudlow_boink/32/320_2.png) [@Thudlow\_Boink](https://boards.straightdope.com/u/Thudlow_Boink)\ **Post date:** [February 12, 2016, 11:05pm UTC](https://boards.straightdope.com/t/thomas-aquinas-logical-flaws/745954/32 "2016-02-12T23:05:14Z")
> [@Little\_Nemo](#): > > I’d say these these arguments illustrate what’s wrong with Aquinas. He follows a ling of reasoning until the point where he reaches a paradox and then he declares that God lies just beyond that paradox. Well, he’s arguing by _reductio ad absurdum_, and he considers an infinite backwards chain (of causes, or movers) to count as an _absurdum_. > [@](#): > > The two arguments you cite start with the premises that everything in motion must have something that set it in motion and **anything that exists must have a cause that made it exist**. After juggling with some supposed logic, **Aquinas concludes that God is the thing which is in motion** that nothing set in motion and is the thing that exists without anything causing it to exist. > > But wait…if you go back to the premises these arguments were built on, they were that nothing can exist with these attributes. Therefore if God must have these attributes in order to be God and nothing can exist with these attributes, then God cannot logically exist. If you’re critiquing **Charlie Thomas** ’s formulation of the arguments, you may have a point. But I think you, and/or he, may be changing Aquinas’s words in subtle but important ways. Specifically, I don’t think Aquinas does say that God is in motion (in the sense in which he is using the term). And Aquinas never says “anything that exists must have a cause that made it exist.” What he says is that **nothing causes itself to exist**. ---
**Author:** ![Subterraneanus](https://avatars.discourse-cdn.com/v4/letter/s/a183cd/32.png) [@Subterraneanus](https://boards.straightdope.com/u/Subterraneanus)\ **Post date:** [February 12, 2016, 11:13pm UTC](https://boards.straightdope.com/t/thomas-aquinas-logical-flaws/745954/33 "2016-02-12T23:13:07Z")
> [@The\_Hamster\_King](#): > > … his conclusion contradicts his premises. If everything in motion requires a mover then\* there can be no prime mover\*… The standard response to this criticism comes from Augustine: God is not a causal link _in_ the chain of causes (that would indeed lead to a contradiction between premise and conclusion), but an event _outside_ the chain of causes that causes the _chain as a whole_. Hume clearly explains the problem with this line of reasoning: To explain a chain of causes one need only explain each link in the chain, such that explaining the “chain as a whole” is redundant. We do not need to invoke a cause for the chain as a whole (God) in order to explain the causal chain, only a cause for every event in the chain (perhaps in an infinite regress). Asking after a cause for the “chain as a whole” is like asking where the “house as a whole” is after someone has just shown you the entire house one room at a time. ---
**Author:** ![Subterraneanus](https://avatars.discourse-cdn.com/v4/letter/s/a183cd/32.png) [@Subterraneanus](https://boards.straightdope.com/u/Subterraneanus)\ **Post date:** [February 12, 2016, 11:14pm UTC](https://boards.straightdope.com/t/thomas-aquinas-logical-flaws/745954/34 "2016-02-12T23:14:57Z")
> [@Charlie\_Thomas](#): > > St. Thomas Aquinas, the guy who wrote the Summa Theologica and reconciled religion and logic (hell, even _combining critical aspects of the two_) he was attempting to prove the existence of God, by logic alone, at a time when logic and religion appeared incompatible. I just read the Summa Theologica. If you ask me, he proved the doubters wrong and then some. > > Are there any particular flaws in his reasoning, i.e. the Five Proofs? Feel free to rip it to shreds and grind it into oblivion and then nuke the oblivion. > > (Don’t limit yourselves to the Five Proofs either.) > > As usual, civil responses, please. Now read Hume’s _Dialogues Concerning Natural Religion_, and then get back to us. ---
**Author:** ![Thudlow\_Boink](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/thudlow_boink/32/320_2.png) [@Thudlow\_Boink](https://boards.straightdope.com/u/Thudlow_Boink)\ **Post date:** [February 12, 2016, 11:17pm UTC](https://boards.straightdope.com/t/thomas-aquinas-logical-flaws/745954/35 "2016-02-12T23:17:15Z")
> [@Czarcasm](#): > > In other words, how does the argument lead to _your_ god, and your god _only_? Aquinas never says it does. [After giving arguments for God’s existence, he goes on to discuss God’s nature/properties.](http://www.newadvent.org/summa/1.htm) ---
**Author:** ![The\_Other\_Waldo\_Pepper](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/the_other_waldo_pepper/32/12370_2.png) [@The\_Other\_Waldo\_Pepper](https://boards.straightdope.com/u/The_Other_Waldo_Pepper)\ **Post date:** [February 12, 2016, 11:18pm UTC](https://boards.straightdope.com/t/thomas-aquinas-logical-flaws/745954/36 "2016-02-12T23:18:47Z")
> [@Subterraneanus](#): > > The standard response to this criticism comes from Augustine: God is not a causal link _in_ the chain of causes (that would indeed lead to a contradiction between premise and conclusion), but an event _outside_ the chain of causes that causes the _chain as a whole_. Which, again, raises the question: could there be dozens or hundreds of such events “outside” the chain of causes? ---
**Author:** ![Subterraneanus](https://avatars.discourse-cdn.com/v4/letter/s/a183cd/32.png) [@Subterraneanus](https://boards.straightdope.com/u/Subterraneanus)\ **Post date:** [February 12, 2016, 11:26pm UTC](https://boards.straightdope.com/t/thomas-aquinas-logical-flaws/745954/37 "2016-02-12T23:26:42Z")
> [@The\_Other\_Waldo\_Pepper](#): > > Which, again, raises the question: could there be dozens or hundreds of such events “outside” the chain of causes? The argument itself presupposes that every event has a cause, and so is part of a causal chain. A cause outside of the chain is invoked only to accommodate the concept of an uncaused cause/unmoved mover. I’m not sure what your question even means, let alone how to answer it. ---
**Author:** ![The\_Other\_Waldo\_Pepper](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/the_other_waldo_pepper/32/12370_2.png) [@The\_Other\_Waldo\_Pepper](https://boards.straightdope.com/u/The_Other_Waldo_Pepper)\ **Post date:** [February 12, 2016, 11:31pm UTC](https://boards.straightdope.com/t/thomas-aquinas-logical-flaws/745954/38 "2016-02-12T23:31:17Z")
> [@Subterraneanus](#): > > The argument itself presupposes that every event has a cause, and so is part of a causal chain. A cause outside of the chain is invoked only to accommodate the concept of an uncaused cause/unmoved mover. > > I’m not sure what your question even means, let alone how to answer it. I wonder whether – if we can invoke a cause outside of the chain to accommodate the concept of an uncaused cause or an unmoved mover – we can invoke a cause outside of the chain to accommodate the concept of nine uncaused causes, or ten unmoved movers. If we can so accommodate _one,_ can we thusly accommodate _sixty?_ ---
**Author:** ![Little\_Nemo](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/little_nemo/32/3120_2.png) [@Little\_Nemo](https://boards.straightdope.com/u/Little_Nemo)\ **Post date:** [February 13, 2016, 12:43am UTC](https://boards.straightdope.com/t/thomas-aquinas-logical-flaws/745954/39 "2016-02-13T00:43:04Z")
> [@Thudlow\_Boink](#): > > Well, he’s arguing by _reductio ad absurdum_, and he considers an infinite backwards chain (of causes, or movers) to count as an _absurdum_. > > If you’re critiquing **Charlie Thomas** ’s formulation of the arguments, you may have a point. But I think you, and/or he, may be changing Aquinas’s words in subtle but important ways. Specifically, I don’t think Aquinas does say that God is in motion (in the sense in which he is using the term). > > And Aquinas never says “anything that exists must have a cause that made it exist.” What he says is that **nothing causes itself to exist**. Quibbling over the terms doesn’t invalidate my point. Aquinas’ argument is that nothing can exist without something external to it. But then he creates a special case for God and says God can exist without something external to God. It doesn’t hold up. If Aquinas’ premise is correct then the premise proves God can’t exist. And if God exists then the premise is disproven by God’s existence. Either the premise disproves God or God disproves the premise. And that means you can’t use the premise to prove God. ---
**Author:** ![Charlie\_Thomas](https://avatars.discourse-cdn.com/v4/letter/c/77aa72/32.png) [@Charlie\_Thomas](https://boards.straightdope.com/u/Charlie_Thomas)\ **Post date:** [February 13, 2016, 1:25am UTC](https://boards.straightdope.com/t/thomas-aquinas-logical-flaws/745954/40 "2016-02-13T01:25:38Z")
**Little Nemo** , you said this: “And Aquinas never says “anything that exists must have a cause that made it exist.” What he says is that nothing causes itself to exist.” There’s no fundamental difference between those two statements whatsoever. Just like the movie Grease, at the drive-in, when Danny’s trying to console Sandy: “Sandy, we didn’t go together. We just went together.” “Nothing causes itself to exist” is the same statement as “everything that exists must have a cause that made it exist.” It’s just using 11 words as opposed to 5. It’s the same thing. [Previous page](https://boards.straightdope.com/t/thomas-aquinas-logical-flaws/745954.md?page=1) [Next page](https://boards.straightdope.com/t/thomas-aquinas-logical-flaws/745954.md?page=3)