Bad Reasons To Believe In God: Aquinas’ Argument From Motion

I was rightly called out by a believer the other day on Twitter – he asked me for my arguments against St. Thomas Aquinas’ proofs for god and I couldn’t direct him to any single post that addressed them. I mean, I’ve touched on each of these five arguments before but they were short paragraphs buried in posts about other things. I’d never actually tackled them head-on. When I started blogging as Godless Mom, I had never before thought about any of these arguments. My first attempt at taking down any sort of argument for God was when I posted about Pascal’s Wager in 2014. Where I grew up, god wasn’t really a topic that came up all that much.

Despite the fact that I’d literally never considered it before, I think I did alright knocking down Pascal’s Wager, but let’s be real for a sec: that’s no accomplishment. All it takes is a moment’s thought to see the flaws in Pascal’s Wager. So, I figure it’s about time to tackle a new argument and where better to start than with St. Thomas Aquinas?

Aquinas outlined the Five Ways or five proofs for God in his book Summa Theologica, written sometime in the 1200s. Yes, it would appear that the middle ages produced the best arguments for god, and I use the term “best” loosely because, as many of you already know, these proofs would have more use written as limericks – at least then they’d be entertaining.

The five proofs for god, according to Aquinas, are:

  1. The Argument From Motion
  2. The Argument From Causation
  3. The Argument From Contingency
  4. The Argument From Degree
  5. The Argument From Final Cause Or Ends

Today, we’re going to take a look at the first proof, the argument from motion. It goes something like this:

1: We can observe that some things are in motion.
2: Whatever is in motion is put in motion by something outside of itself (a mover).
3: There cannot be an infinite string of movers causing motion.
4: So, there must be a first, unmoved mover.
5. That unmoved mover is what we know as god.

Now, when theists approached me asking how I could possibly take down the arguments for god by St. Thomas Aquinas, I admit, I was a little bit intimidated. As we’ve covered before, I’m no philosopher or scientist nor any sort of scholar. Sure, I took a philosophy class in college, but I wouldn’t ever even begin to suggest I am in any way knowledgeable on the subject. So, yeah, I was a little anxious about taking on such a noted name in philosophy as Aquinas. I was expecting a real test of my wetware; at least a stronger argument for god than Pascal had offered up.

So, I guess you can imagine my disappointment when I actually sat down and read this first argument. It’s so holey, Jesus is jealous of it.

I mean, sure, the argument works…if you accept each and every premise and are willing to take a giant leap at the end. But I doubt there are many clear-thinking people willing to do that. There are problems with just about every premise and the conclusion itself ignores tons of possibilities. Let’s go through it, line by line, and take a look at all of these problems. The first premise, we can observe that some things are in motion, is something I think we can all agree on, so let’s move onto the second premise:

Whatever is in motion is put in motion by something outside of itself (a mover).

This premise presupposes that the natural state of the universe and everything in it is rest – that motion must be caused. This is not something we know. It’s not something any of us need to believe or accept. We do not know that all motion requires a mover outside of that which is being moved. Two steps in and we’re already being forced to accept something that cannot be demonstrated. However, if we did accept this premise and we moved on to premise three, we encounter even more problems there.

There cannot be an infinite string of movers causing motion.

My first question here is, how do you know? How can this be demonstrated to me? Why must we accept this? Do we know for sure that infinite causal regression is impossible? For argument’s sake, let’s pretend that we do; let’s accept this premise and move onto the next:

So, there must be a first, unmoved mover.

If there is a mover that didn’t need to be moved, then not everything that moves requires a mover. If everything in motion requires a mover, then there cannot be an unmoved mover – the existence of such would break the rule that everything that moves requires a mover. This premise cancels out the second premise, that whatever is in motion is put in motion by something outside of itself (a mover). We cannot accept both premises at the same time, unless, of course, we’re talking about an unmoved mover that does not move. Unfortunately for Aquinas, that cannot be the god of the Bible, because we know the god of the Bible is said to have moved. Once again, for the sake of moving forward, let’s just fake like we can accept all of these problematic premises and move to the conclusion:

That unmoved mover is what we know as god.

If we’re extra generous and we accept all the failing premises that lead to this conclusion, all we’ve discovered is that there is an unmoved mover. It is a giant leap to go from unmoved mover to the Judeo-Christian God of the Bible. The best we have done here if we accept the faulty premises leading to the conclusion in Aquinas’ first way, is give a good reason for deism. Hypothetically, we’ve proven a faceless, featureless, nameless mover about which we know nothing. We don’t even know that this mover is intelligent; we have no idea if this mover has desires or plans or rules. We don’t know if this mover is merciful or wrathful or omniscient. We certainly do not know that this mover transformed into a human, came down to earth to be crucified and turned a bit of water into wine while he was here.

As such, St. Thomas Aquinas’ argument from motion can just as easily be an argument for the Big Bang, Shiva or the Flying Spaghetti Monster. Aquinas has failed to show how he got from “unmoved mover” to Yahweh.

Aquinas’ first way, therefore, is a huge failure from beginning to end. It has failed to lead us to any sort of knowledge whatsoever, let alone the knowledge of a creator god who deeply cares about whether or not you touch your own naughty bits. It is a self-debunking argument, as it proposes first that all things that move require a mover and then goes on to propose an unmoved mover. In short, this argument is sheer nonsense and can easily be tossed into the same pile as the massively flawed wager put forth by Blaise Pascal.

Next week, we’ll take a look at St. Thomas Aquinas’ second way, the argument from causation which, as you might be able to predict, will go the same way as the first. He didn’t seem like the most creative fella in the middle ages, that’s for sure. Make sure you’re subbed to my newsletter (top right of the sidebar) to be notified when I post that. You can also follow me on Twitter, @godless_mom, and I will post it there, too.

What do you think of Aquinas’ argument from motion? Let me know where you object and where you agree. I’d also like to know what you think of my response? Did it miss the mark? Do you agree with me? Let me know in the comments and we can discuss!

Image: Creative Commons/Pixabay

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What Are Your Thoughts?leave a comment
  • Priya Lynn

    Way to go Courtney 🙂

    The best they’ve got really is pathetic, isn’t it?

    Well done!

  • If I understand his ‘argument’ realizing that this was a long time before Issac Newton. God = gravity.

    Once again science and faith can coexist??

  • Michael Neville

    Aquinas liked the Special Pleading fallacy so much that he used it at every opportunity.

  • ThaneOfDrones

    The way religion works:
    Christianity’s greatest theological thinker lived over 700 years ago. Apologists have been rehashing and regurgitating his arguments ever since.

    The way science works:
    There are several candidates for science’s greatest thinker (Newton, Einstein, et al.). Once they shared their ideas, other scientists were able to verify them and then build on them to discover new things that would totally amaze that thinker if he were still around.

  • Milo C

    I’ll happily share this.

  • Raging Bee

    He didn’t seem like the most creative fella in the middle ages, that’s for sure.

    I think just about all serious thinkers at that time — and several centuries after as well — were under the constraint of a religious establishment that feared and hated all forms of independent inquiry; therefore any philosopher or scientist who wanted to get published and keep any academic freedom, had to make a show of using his formidable genius to prove the existence of God (their god, not the other guy’s god, mind you), otherwise he and whatever “school of thought” built up around him be suspected of potential heresy or apostacy. So here we have Aquinas jumping through the necessary hoops, just as other great thinkers did before and after. It didn’t have to be convincing, since no one was going to step up and debunk it.

  • Raging Bee

    Yes, as long as faith is retconned as necessary to conform to science.

  • JohnCalla

    Reading your analysis it seems that maybe you are midwit IQ or thereabouts?

    Generally, midwits believe themselves to be a lot more intelligent than they actually are. That’s why they believe they can so easily dismiss the Summa with 15 minutes of thinking and a blog post.

  • Gustavo Rodríguez

    Aquinas’ argument clearly fails at premise number 2. In order to talk about start of motion, we need an absolute frame of reference where “rest” makes sense. If we look at a tree, we could say it is at rest. The problem is that it isn’t, since the Earth is moving around the Sun, and the Sun moves around the Milky Way’s center, and the Milky Way is moving with respect to other galaxies, and so on. So, an object that is at rest for an observer is at motion for another. Thus, “start of motion from rest” is a concept that make no sense, at least in Galileo’s (and now, in Einstein’s) principle of relativity, since the concept of “rest” cannot be objectively defined. Also, Aquinas assumed that motion must require a mover because we observe (on Earth) that moving bodies come to rest (with respect to Earth itself). Of course, Aquinas didn’t know anything about friction forces and energy dissipation. Newton’s first law (and afterwards, momentum conservation principle) states that a moving object will remain moving at constant velocity unless a force acts on it. Thus, bodies at motion can be in this state literally forever. Newtonian mechanics show then that a prime mover is not needed to understand motion at all.

  • Gustavo Rodríguez

    The summary of this post could essentially be: “Aquinas’ arguments were basically special pleading fallacies”. So, yes, a blog post and 15 minutes of thinking dismiss the Summa.

  • disciple_of_sithrak

    Would you like to point out where she went wrong?

  • Jim Jones

    I have terrible trouble getting believers to define ‘god’.

    Often, they go away once they have tried for a while and realize it’s way harder than expected.

  • Jim Jones

    Why is it that so many people CAN easily dismiss apologist arguments?

  • Ficino

    You are a Russian troll?

  • Ficino

    Hi Courtney, it’s great that you are tackling Aquinas’ Ways. As an atheist who knows a good deal about Aristotle and Aquinas but by no means everything, I’ll throw out a couple of thoughts. To explain in detail would wind up too long, aargh.

    1. By “motion” Aquinas does not mean only locomotion. He means basically any change, including alteration and growth/decay.
    2. Aquinas’ focus is on a series of movers, not going back in time, but operating all at once in one system directed by a first mover. It’s not a series going back in time like one car hitting another car hitting another car back to infinity. Aquinas means a series like a feather moved by a stone moved by a stick moved by a hand moved by a human … all the way up to God, all operating at once.
    3, By “move” Aquinas does not mean “be in motion.” He means, “move something else.” I.e. Aquinas uses “move” only transitively, not intransitively. That goes back to Latin. In Latin, “hoc movet” means “this moves [something else].” “Hoc movetur” means “this is moved/is in motion.” So when Aquinas says that the first mover moves something else, he also says that the first mover itself is not in motion. It is the Unmoved Mover. He cares about this because, following Aristotle, he holds that anything in motion is not wholly actual. Instead, it has some potentiality, because it’s potentially at its destination but not actually there yet. But the UM has no potentiality at all. It is only actual. So it cannot be in motion, only moving other things.
    So when you write: “If everything in motion requires a mover, then there cannot be an unmoved mover – the existence of such would break the rule that everything that moves requires a mover.” I think you’re getting tricked by English’ failure to represent Latin accurately. The existence of an unmoved mover does not break Aquinas’ own rule, because the UM is not in motion. The rule translated more accurately states, “everything that is in motion requires a mover.” The UM does not require a mover because it is not in motion, but on this rule it can still move other things, i.e. cause them to change from potentially F to actually F.

    Well, this is already too long. If you’d like to discuss further, I’ll do my best and will welcome your and others’ insights.

  • se habla espol

    It’s even worse than you explain. Some 600 years after quinas, people started measuring things in the universe, in order to find this absolute frame of reference that the first premise would require. They failed to find it.
    Einstein studied their measurements and realized that not only was there no absolute frame in which ‘rest’ could exist, but that the only absolute of the universe is the speed of light—motion, not rest, is the natural state of everything. Let me correct the statement in the article:

    We do not know that all motion requires a mover outside of that which is
    being moved. Two steps in and we’re already being forced to accept
    something that cannot be has been demonstrated false.

    So much for the second premise, and the whole argument.

    Edited to fix markup.

  • Cozmo the Magician

    Cozmo’s Proof of His Dragon Fluffy:
    Anything named Fluffly must be loved
    To love something you must know something
    To know something, it must exist
    Therefore Fluffy the Imaginary Invisible Pet Dragon exists.. Q.E.D (Quality Excrement Delivered)

    BTW, Fluffy DOES do Birthday Parties… (But only when I’m along as the assistant).
    Edit: I was born way too late.. Back then I woluld been considered and absolute GENIUS of lojik and filosify … Mine would be the most downloaded books on thinkins that people gots from project guttenberb O_o

  • Cozmo the Magician

    When you sleep on a bed of nails, every tool becomes a hammer… or umm. something like that.

  • Cozmo the Magician

    Ohhh look. A troll.. And Fluffy just woke up. Guess it is breakfast time.

  • Cozmo the Magician

    Because unlike their target audience, everybody else can actually think?

  • Brian Curtis

    It’s amazing that Aquinas was taken seriously for so long. And in some cases, he still is.

  • Brian Curtis

    That’s the only hope religion has, but far too many zealots are fighting it tooth and nail. How long did it take the Catholics to acknowledge that Galileo was right?

  • ORAXX

    Assigning god to a cause, in no way validates the existence of any particular god. As much as theologians would like it to. Mostly, it’s just mental masturbation.

  • ORAXX

    Additionally, when science advances ideas it does not threaten anyone with eternal damnation for not accepting them.

  • Raging Bee

    Some Catholics are still not on board with that. I remember Pope Palpadict (or maybe one of his underlings?) mumbling something about how “relativity” meant the Church wasn’t really wrong to insist the Earth stood still.

  • wolfypuppy

    My first reaction was “#5 makes numbers 1-4 irrelevant. It’s the same argument still used today: ‘I don’t know, thus God.” But then I looked again: “what we know as god.” Ah ha. So I would just flip the definition around to “If you want to define ‘god’ as ‘stuff I can’t explain,’ then I’m down with it. But then you can’t define ‘God’ as ‘supernatural being.'” Unless you’re also willing to admit that “God” = ‘the anthropomorphization of the stuff I don’t know.” Then you’re no longer a Christian but a Unitarian Universalist who likes to appropriate religious language by taking the supernatural out of it and call these feelings of awe just part of being human. I like this argument, again, because it makes gods irrelevant and unnecessary. I haven’t yet come across a religious person who’s willing to take that step lol. -Sarah

  • Kevin K

    I’ll let the real physicists chime in, but according to Sean Carroll, the first premise is wrong. Aquinas and Aristotle (they’re really Aristotle’s ideas) thought that motion had to be continually impelled, like a car needing a steady accelerator. That’s wrong. An object in motion will stay in motion, unless acted upon by an outside force (in the case of the car, friction tries to stop the car from moving).

    The thing is … everything is in motion, all the time. It’s baked into the laws of physics.

    And there is no evidence to suggest that the initial conditions of this space-time we call the “universe” was stationary, either. So, you can’t regress to an initial “shover of everything” — unless you want to bring the math, in which case the Nobel Prize committee awaits.

    This argument should have been abandoned as soon as Newton published his Principia.

  • Kevin K

    Have you actually read the Summa? What’s your favorite part?

    I couldn’t get through the whole thing because it got to be laughably inane.

    I love the part where Aquinas explains that women were meant to be subservient to men because God made them second and out of a man’s rib.

  • I have not read the whole thing, admittedly. I found the bits I did read fairly silly.

  • Thanks and yeah, they are.

  • It would appear so.

  • Yep.

  • Thank you!

  • Great point and one I hadn’t considered. Thanks!

  • This is a fantastic rebuttal. Lots to think about there.

  • Thank you, Gustavo. This is excellent! I n ow have new points to make should this argument come up again.

  • Really, I had to struggle to stretch it out.

  • In my experience, people who respond with personal insults often have nothing else to offer, else they wouldn’t resort to that.

  • I suspect many of them had never considered how they might define god. Getting them to think about that is halfway to causing doubt, in my opinion.

  • I’d read your book, especially if there is more about Fluffy.

  • I am genuinely dumbfounded that anyone still offers his arguments as actual reasons to believe in god.

  • Cozmo the Magician

    I think you made Fluffly blush (; Hard to tell for sure.

  • Kevin K

    It’s 3 million words! Who has time for that?

  • Tom Hanson

    I would also add that Aquinas never expected to, or tried to prove the Christian God. In this instance about mover and unmoved mover, he felt he could prove what he would call the God of the philosophers (the other guys–per Raging Bee below), and that any actual knowledge of God’s attributes must be taken on faith and that faith can only know it through Revelation and God’s Church through its teaching.

  • David Cromie

    If any one of the premises can be shown to be false, then the whole argument fails, and the conclusion is necessarily false.

  • Tom Hanson

    “I think just about all serious thinkers at that time — and several centuries after as well — were under the constraint of a religious establishment that feared and hated all forms of independent inquiry; therefore any philosopher or scientist who wanted to get published and keep any academic freedom, had to make a show of using his formidable genius to prove the existence of God (their god, not the other guy’s god, mind you), otherwise he and whatever “school of thought” built up around him be suspected of potential heresy or apostacy.”

    You have it precisely backwards, I think. I will quote myself from my comment to Ficino above : “I would also add that Aquinas never expected to, or tried to prove the Christian God. In this instance about mover and unmoved mover, he felt he could prove what he would call the God of the philosophers (the other guys) and that any actual knowledge of God’s attributes must be taken on faith and that faith can only know it through Revelation and God’s Church through its teaching.”
    Aquinas’s others, besides other Catholic Christians, were Byzantine, Jewish, and Islamic philosophers.

  • David Cromie

    The religiot’s BS apologetics usually need lots of qualifying words and nonsequiturs because of a need to confuse the unwary by attempting to sound intelligent and reasonable, thereby hoping to deceive.

  • Cliff

    For someone who is not a philosopher you seem a bit smug about your ability to easily demolish their arguments…And of course, Aquinas is not present to answer or enter into debate with you….And I am not a fan of Aquinas, having read even less of him than your “bits’….

  • Alan

    Ok, I’ll bite.

    This is a poor understanding of the argument from motion. In fact, Thomas isn’t even arguing for a few of the points you tried to make. I can help to make this a little more clear.

    First, “motion” to Thomas is not just a general moving, as in, a baseball moving from one’s hand to another’s glove. Rather, think of a banana on a kitchen counter that moves from green to yellow. Or, think of hot coffee cooling down over time, say.

    Thomas, here, takes his cue from the Aristotelian concept of potency/act. That is, there is potentiality in the coffee to become cool and thus be actualized into being actually cool. In other words, there is an element of potential reality in the hot coffee to actually cool down.

    Now, the hot coffee can only be actualized by something that is already actual. For instance, say the air conditioner in the room caused the potential coolness of the coffee to become actually cold. That is, only things which are already actual can cause a potential to become actualized. Why is the air conditioner something that is actualized? Because, prior to it being turned on, it had the potential to cool the room down, thus needing something already actualized to turn it on, namely myself.

    Why is this concept important to understand? Because if we reject this, as Parmenides did, then our conclusion is that change comes from nothing. Aristotle, in wanting to avoid this irrational conclusion that change comes from nothing, posits that there are potential realities, which is not nothing, extrinsically and intrinsically that cause change.

    Okay, now we need to distinguish between derivative causal power and inherent causal power. Derivative causal power is simply that which is not the first cause. That is, the coolness of the air conditioner contains derivative causal power to cool down the coffee from myself who turned on the air conditioner. Each element in the linear chain has derivative causal power received from things that are already actual. Inherent causal power, on the other hand, is that which has built-in causal power. That is, in a hierarchical chain of events, the infinite regress of derivative causes must be actualized by an unactualized actualizer, i.e. an Unmoved Mover.

    Now it’s precisely this hierarchical series in which Thomas is making his argument from motion about. It’s NOT a linear series of elements that goes all the way back to a first cause in temporal sequence that Thomas is arguing. Rather, it’s a hierarchical series of events that Thomas is arguing. That is, how do these changes we observe in the world exist in the here and now?

    Let’s stay with the coffee example. Obviously, in order for coffee to become cold, the coffee needs to exist in the here and now. That is, in any particular moment it must be true the coffee exists. Why? Why does it exist in the here and now? Why does it exist in the present moment? It is easy here for the non-theist to give me an explanation on how the coffee got here, but that’s not what Thomas is asking. He’s asking what makes it true that finite things that come into being exist in any particular moment. Is it it’s own essence that keeps it in existence? That is, does coffee in and of itself hold itself in existence? If you say, yes it keeps itself in its own existence, then it’s completely irrational. If you say that water was poured through coffee beans, pressurized through heat, and so on, then you would only be telling me how it got here. But we can take this further: how does the water that made the coffee come into existence exist at any moment? How the does the hydrogen and oxygen that make up the water hold itself in existence? How do the sub-atomic particles that hold the hydrogen and oxygen together hold itself in existence? What is keeping all of the changes in existence?

    Therefore, the potential of the coffee to exist at any particular moment is being actualized by the existence of water, which follows its existence from the potential of the atoms being actualized, where these atoms are in existence because of the potential of subatomic particles being actualized. This is the hierarchical series that Thomas is arguing. If you answer that it comes from nothing, then that is illogical and irrational. If you say that an infinite amount of these series of changes is what is keeping it in existence, that would be like saying that a paintbrush that is infinitely long is painting a picture. That is illogical and irrational. You need something that has inherent causal power to use the paintbrush to paint. It can’t do it on its own, even if it is infinite. BTW, Aquinas didn’t care if there were an infinite amount of causes, it would still require an Unmoved Mover, because it’s NOT a linear chain of events that stretches back to the first temporal sequence of a cause. These are only derivative causes that must receive its existence from something that has inherent causal power. This is God.

    Furthermore, Thomas does NOT argue that everything has a cause. He argues that all finite things that come into being through change must require a cause. This can only be accounted to God (by all of the above). God, by definition, is that which does not change and is the totality and wellspring of everything, keeping and holding it all in existence. He is not a being among other beings; he is not something you put under a microscope and say “ah I see his finger. God does exist”. His essence and existence coincide. He is not a being, but being itself; the Unactualized Actualizer.

    Now, finally, Thomas in this section of his Summa is not arguing for the existence of the Christian God. He’s demonstrating the existence, from natural and objective reasoning, that a god does exist.

    I hope this helps. I have to go because my coffee is getting cold

  • Clayton Gafne Jaymes

    No, sorry, those points don’t dismiss the points of which you look to argue against. All you did was say ‘can you demonstrate it??’ and then said well, if you can’t then it isn’t true. Really?? Did you demonstrate that they wren’t true?

    You also fail to understand that to say that ‘god moved’ doesn’t mean that he was moved from His place. As a matter of fact His moving is what put other things into motion. And His first ‘movement’ could have been as simple as a thought in His mind that gave Him ‘want’ to ‘create’ ‘bring into existence’ something else which He could also ‘move’ toward ‘in love’.

  • You don’t need to be a philosopher to recognize a terrible argument.

  • You don’t need to demonstrate that something is not true to dimiss it. If you cannot demonstrate it is true, there is no reason to believe it. Otherwise, you’d have to accept every claim ever made that cannot be disproven, in which case, I’d like to tell you about my gnome. He lived in my garage and has plans to end the world in five days if you don’t transfer $10,000 to me today. You can’t prove he doesn’t exist so if you want to drop me an email, I’ll give you my PayPal address.

  • David Cromie

    Magic, that is the answer!

  • Polytropos

    For Aquinas’ argument from motion to work the universe has to be a kind of enormous orrery that needs to be wound up by some external person. Presumably that’s what Aquinas thought the universe was, which is understandable enough considering he lived in the 13th century and had no knowledge of modern cosmology, gravity, electromagnetic forces, relativitiy etc. Even then his argument doesn’t prove the existence of the Christian god, but perhaps Aquinas, being a 13th century friar, was unable to conceive of any first mover other than the Christian god.

    I think this explains why the middle ages produced the best arguments for god: the god hypothesis only appears persuasive if you have a pre-scientific understanding of the universe.

  • Yes, we’ve come a long way and learned a lot that get in the way of his arguments.

  • Loren Petrich

    Another problem: is there only one unmoved mover? Aquinas got his arguments from Aristotle, and Aristotle proposed that there are 47 or 55 unmoved movers that keep the celestial spheres moving.

  • Fantastic point – Aquinas’ argument leaves so many questions.