Fr. Robert Barron Revisits the Argument from Motion

October 21, 2014 by 16 Comments

I love his Thomism for Joe SixPak stuff:

Revisiting the Argument from Motion

By Very Rev. Robert Barron

Father Robert Barron is the founder of the global ministry, Word on Fire, and the Rector/President of Mundelein Seminary. He is the creator of the award winning documentary series, “Catholicism”  and “Catholicism:The New Evangelization.” Learn more at www.WordonFire.org 

One of the unintended but happy consequences of the emergence of the new atheism is a renewed interest in the classical arguments for God’s existence. Eager to defend the faith that is so vigorously attacked today, Catholic apologists and evangelists have been recovering these rational demonstrations of the truth of God; and the atheists, just as eager to defend their position, have entered into the fray. In the process, these ancient arguments, long thought by many to be obsolete, have found a new relevance and have been brought to greater clarity through the give and take of both critics and advocates.

Thomas Aquinas famously laid out five arguments for the existence of God, but he characterized one of them as “the first and more manifest way.” This is the proof from motion, which can be presented simply and schematically as follows. Things move. Since nothing moves itself, everything that is moved must be moved by another. If that which causes the motion is itself being moved, then it must be moved by another. This process cannot go on to infinity. Therefore, there must exist a first unmoved mover, which all people call God.

In order to avoid misunderstanding (and it’s fair to say that this argument has been misunderstood for centuries), several observations are in order. When Aquinas speaks of motion, he means change of any kind, not simply change of location. Growth in wisdom, fluctuation in temperature, birth, death, etc. are all examples of motion, or in his more technical language, the transition from potency to actuality. Once we grasp what Aquinas means by motion, it is relatively easy to understand why he insists that nothing can move or change itself. Whatever is in motion must be in potency, while that which causes change must be in actuality, just as the one learning French doesn’t yet possess the language and the one teaching it does. Now since the same thing cannot be potential and actual at the same time in the same respect, nothing can be, simultaneously, both mover and moved. No one, strictly speaking, teaches himself French.

But let us suppose that the cause which is putting something in motion is itself being put in motion; then by the same principle, its change must be prompted by another. But this chain of moved movers cannot be indefinite, since the suppression of a first element would imply the suppression of every subsequent mover and hence, finally, of the motion that is evident to our senses. In regard to the negation of this sort of infinite causal series, the twentieth century philosopher Bertrand Russell had a particularly unhelpful observation. Russell opined that Thomas Aquinas couldn’t imagine such a series, because medievals hadn’t yet come to terms with the idea of infinite sets. Nothing could be further from the truth. Aquinas had absolutely no problem imagining infinite series, since he speculated about them all the time. What he is denying is the possibility of an infinite causal series in which each element in the chain is here and now dependent upon the influence of a higher cause. Think of a pen which is here and now being moved by a hand, which is here and now being moved by muscles, which are here and now being moved by nerves, which are here and now being stimulated by the brain, which is here and now being sustained by blood and oxygen, etc. If we suppress the first element in this sort of chain, the entire causal nexus would collapse and the motion under immediate consideration would not be adequately explained. Therefore it follows that a prime mover exists, which is to say, an unactualized source of actualization, an unenergized energizer, an ultimate source of all of the change in the cosmos.

Now there are many atheists and agnostics who acknowledge that this demonstration is logically airtight but who quarrel with the association that Aquinas makes, almost casually, at the very end:  “and this all people call God.” There might indeed, they say, be a prime mover or uncaused principle but this first element in the causal chain might be matter or energy or some such physical element. Many point to the famous law of the conservation of energy and conclude that the fundamental stuff of the universe just undergoes continual change of form throughout time.

In order to answer this objection, we have to examine the nature of the unmoved mover a bit more carefully. That which is truly the uncaused or unmoved source of energy must be fully actualized (actus purus in Aquinas’s pithy Latin), which means that it is not capable of further realization. But energy or matter is that which is capable of undergoing practically infinite change. Energy or matter is endlessly malleable and hence about as far from actus purus as can be imagined. A rather simple thought experiment shows that such primal physical elements cannot be the unmoved mover. Neither matter nor energy exists as such but always in a particular form or configuration. In regard to either, one could always ask, what color is it, at what velocity does it move, under what conditions does it exist? A given piece of matter is one color, but it could be any other color; energy is at one quantum level, but it could be at any other. Therefore, we are compelled to inquire about the cause that made it to exist this way rather than that. We can appeal, of course, to some other material cause, but then we are compelled to ask the same question about that cause, and having recourse indefinitely to similarly material movers won’t get us anywhere closer to an ultimate explanation. The philosophical dictum that sums up this state of affairs is “act precedes potency.” The first cause of change cannot be itself subject to change.

The unmoved mover is that which exists in a state of pure realization, that which cannot be improved in its being, that which simply is, that which is utterly in act. Do you see now why Thomas Aquinas equated it with God?

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  • http://hjg.com.ar/ Hernán J. González

    > When Aquinas speaks of motion, he means change of any kind, not simply change of location.

    Well, then he should have said “change” instead of “motion”, no?

    > Aquinas had absolutely no problem imagining infinite series, since he speculated about them all the time.

    Baseless hyperbole. Give me three examples.

    > But this chain of moved movers cannot be indefinite, since the suppression of a first element would imply the suppression of every subsequent mover and hence [… ] If we suppress the first element in this sort of chain, the entire causal nexus would collapse

    Begs the principle. Of course, if we postulate that there is “third” element in the chain, then we must conclude that there is a “first” one. “There must be a first element” because “if we supress it”…. Cannot you see the reasoning circle?
    With that argument, the mathematical concept of the integer (positive and negative) numbers without a “first number” if absurd: “if there were not a first integer number, then there would not be a second, a third, etc…” Good grief.

    > The first cause of change cannot be itself subject to change.
    Efficient cause? The argument does not follow. Formal cause? Ok, let’s call it “laws of physics” and “laws of logic” – they don’t change.

    I appreciate Fr. Barron, but al this -include those mappings of medieval concepts to modern physics concepts- looks desperately weak to me.

    I personally believe that any revisitation of Aquinas proofs that refuses to admit the enormous changes in mindset that we have with respect to the c. XIII (scientific, yes, but not “merely” scientific – and not only scientific – think of the grave critiques of Hume to the foundations of “cause” concepts, and Kant, and … etc etc …), and the great difficulties that this implies when we want to actualize the demonstration for us (without a priori deciding if it can be saved or not)… al this causes more harm than good.
    And, in particular, I believe that this kind of “proof” should be left completely out of popular catholic apologetics. It not only fails to convince unbelievers, it even causes uneasiness and confusion in believers. This simply does not help anynone.

    • James H, London

      Thank you for your wonderful illustration of someone who just doesn’t understand the argument.

      “Well, then he should have said “change” instead of “motion”, no?”
      Why? This is needless nitpicking. We have a slightly different use for the term, but the point remains.

      “mathematical concept of the integer… if absurd [sic]”

      Irrelevant. Integers do not cause each other to exist. Let’s translate things a bit for you: if the chain of events was to be broken, would the events continue? Obviously not, therefore the reasoning is not circular. As a simplified illustration, imagine a universe comprising nothing but a series of interlocking cogs, one meshing with the next. Assume that these cogs, when discovered, are moving. Now, how can these cogs start moving by themselves? They can’t. That which causes their motion is by definition not another cog, and if you think it is, you have to consider what caused *that* to move – and we’re back where we started. We call that which started the cogs moving the Prime Mover.

      Hume’s ‘grave’ critique was no slam dunk. He seems not to have even read Aquinas (which isn’t really surprising, since Hume was Protestant).

      For a withering critique of the daft ‘So who created God?’ argument, proceed to Edward Feser’s posting:
      http://edwardfeser.blogspot.co.uk/2014/09/the-straw-man-that-will-not-die.html

      • Newp Ort

        Feser is condescending and rude in his writing. He gives a poor explanation of the Four Causes and then follows it with put-downs to those who don’t immediately understand or agree with his reasoning. (My opinion about The Last Superstition, anyway.)

        He seems more focused on withering than critique.

        • Be polite

          His criticisms (in The Last Supperstition) are aimed at the “expert” analysis offered by the best “New Atheism” has to offer. Which isn’t much really. If you have a problem with condescension and rudeness, you must hate Dennett, Harris, Dawkins, and the late Christopher Hitchens. Granted one does expect such behavior from those four. Perhaps you’re right and we should hold Dr. Feser to a higher standard. Then again, I found TLS to be quite tame. Some snark and harshness? Sure.

          Now, as far as rudeness goes. A quick glance at your comment history demonstrates how quick you’re willing to descend into the pit of rude. For all I know you might’ve been justified in your rudeness. I’m sure you believe you were. Doesn’t matter really. One must demand others bear a burden they aren’t willing to bear themselves though.

          • Newp Ort

            Oh yeah, well screw you too!
            😉

    • Greg Brown

      > Well, then he should have said “change” instead of “motion”, no?

      Aquinas wrote in Latin. The correct translation of ‘motus’ is ‘change’, not ‘locomotion’ or ‘movement’.

      > Baseless hyperbole. Give me three examples.

      I won’t bother finding three examples, but he admits the particular sorts of series (those on the other side of the distinction relevant to the First Way) can contain infinitely many elements here:

      “In efficient causes it is impossible to proceed to infinity “per se”–thus, there cannot be an infinite number of causes that are “per se” required for a certain effect; for instance, that a stone be moved by a stick, the stick by the hand, and so on to infinity. But it is not impossible to proceed to infinity “accidentally” as regards efficient causes; for instance, if all the causes thus infinitely multiplied should have the order of only one cause, their multiplication being accidental, as an artificer acts by means of many hammers accidentally, because one after the other may be broken. It is accidental, therefore, that one particular hammer acts after the action of another; and likewise it is accidental to this particular man as generator to be generated by another man; for he generates as a man, and not as the son of another man. For all men generating hold one grade in efficient causes–viz. the grade of a particular generator. Hence it is not impossible for a man to be generated by man to infinity; but such a thing would be impossible if the generation of this man depended upon this man, and on an elementary body, and on the sun, and so on to infinity.”
      http://www.newadvent.org/summa/1046.htm#article2

      Strictly speaking, the quantity of ‘infinity’ is not the problem here. The problem would arise also if, somehow, a per se series went in a circle without any ‘first mover’ (where ‘first’ here means that the cause is not dependent on anything else, not necessarily that it stands at the front of some linear queue).

      > Begs the principle. Of course, if we postulate that there is “third” element in the chain, then we must conclude that there is a “first” one.

      Nothing rides on the numerical terms employed here. Typically Thomists speak of every contingent, created cause being a “secondary” cause whereas God is a “primary” cause; this can sometimes give the appearance of begging the question. But it only anticipates the conclusion without assuming it; one could alternatively call the causes with which we are familiar “dependent” causes (in the sense that they depend on something else for their causal efficacy), and it follows that a “non-dependent” cause of a certain sort would be required if the dependent causes act at all.

      > Efficient cause? The argument does not follow. Formal cause? Ok, let’s call it “laws of physics” and “laws of logic” – they don’t change.

      The reason that the first cause cannot be subject to change is that, if it were, it would be dependent in the relevant sense and would not actually explain what (it is claimed) it explains. So assuming that the change of contingent things has an explanation, it does follow.

      I am not sure what the laws of physics are, rather than empirical generalizations of the dispositions of matter. They don’t themselves _explain_ anything; one can’t explain why the table is attracted gravitationally to the ground by the fact that matter always behaves that way, or has in all other circumstances. One has to posit actual dispositions in the matter to explain the regularity. The laws of physics are not entities in some Platonic third realm that ‘make’ things behave ‘according to the laws of physics.’ Likewise, I am not sure what appealing to ‘the laws of logic’ will do, since they are not causally active and don’t explain why things happen. (They are also highly interest-dependent. One might use quantificational logic in mathematical contexts but hold that it does not properly translate natural language.)

    • Dan13

      ” I believe that this kind of “proof” should be left completely out of popular catholic apologetics. It not only fails to convince unbelievers, it even causes uneasiness and confusion in believers. This simply does not help anynone.”

      I agree that it fails to convince unbelievers (with a few exceptions) but how does it create uneasiness in believers? I’m not convinced by any of Aquinas’ proofs (or Anslem’s for that matter), but it doesn’t really make much of a difference for me. Unless you think that teaching them would be a waste of catechists’ time?

    • jroberts548

      Aquinas didn’t write in English. He didn’t call it “motion” or “change.” It’s too bad you’re so much more knowledgeable than people were in the 13th century, or you might have known that.

      • http://hjg.com.ar/ Hernán J. González

        Do I really need to state that I already knew that, that I don’t consider myself “much more knowledgeable than people were in the 13th century”, that I consider Aquinas the greatest mind in theology, that I admire his work so much that I spent a month (full time) of my life converting the Summa to html so that it could be freely acccesible in the web (in spanish)?
        Is all that contradictory with believing that the (our) modern mindset is very different, that it’s not enough to make those easy mappings “motus” => “physical changes” to make those proofs into something understadable and fruitful for us, catholics of 21st century?
        I know that “motus” is not the same as “motus localis”, but the fact remains that the later (plain “motion”) is the prototypical. And that, not me (an engineer with no philosophical training or aptitude) but a Garrigou Lagrange had troubles (I’d say more: he failed miserably) at the apories related with the inertial laws: the notion that “motion” (motus localis) begs for an (efficient, actual) cause is problematic once one accepts that motion (and hence “motus”) is relative, etc.

        And no, I’m not saying that Galileo+Newton refute the proof from motion, I’m saying that they (together with an enormous pile of physical, cosmological and philosophical developments) requires a good deal of work (thinking) to make them acceptable -or even understandable- to us. I also say that the fact that such a purely philosophical (not theological) proof is rejected by almost all modern philosophers should not easily be dismissed with the argument that “they are not catholics” (some of them are, BTW) or that “truth does not depend on votes”.

        That I don’t really understand the Aquinas’ proof? Sure! I take that for granted. I neither understand most of philosophy (be Aristotle, Kant or Husserl). That’s a pity (somehow it’s even a intellectual humillation for me, given that I tried and failed) but I can live with that, as most people do. What would be more tragic, for me, is to believe that I understood it. And try to use that to discuss with atheists. Or, worse, to confuse that belief with religious faith.

        People here are quick to assume that anyone who rejects Aquinas’ proof “doesn’t understand it”. Speaking of thought experiments, lets imagine this one: pick the readers of catholic apologetics (for example, those who read Fr. Barron’s piece) who accept that proof, and evaluate how many of them understand it.

        Flannery O’Connor, about 50 years ago, wrote (emphasis mine) :

        “… is to our misfortune that they [some protestant theologians] are much more alert and creative than their Catholic counterparts. We have very few thinkers to equal Barth and Tillich, perhaps none. This is not an age of great Catholic theology. We are living on our capital and it is past time for a new synthesis. What St. Thomas did for the new learning of the 13th century we are in bad need of someone to do for the 20th ”

        • Greg Brown

          > I also say that the fact that such a purely philosophical (not theological) proof is rejected by almost all modern philosophers should not easily be dismissed with the argument that “they are not catholics” (some of them are, BTW) or that “truth does not depend on votes”.

          Just about every philosophical argument is rejected by the majority of philosophers. The reasons people discuss things philosophically is that it is difficult to reach a conclusion.

          > What would be more tragic, for me, is to believe that I understood it. And try to use that to discuss with atheists. Or, worse, to confuse that belief with religious faith.

          It would be pretty bad to do any of those things, but no one is suggesting that you should claim to understand something you don’t or present an argument to atheists without understanding it yourself. People are certainly not implying that your faith is somehow deficient for not understanding it, or that theirs is superior for understanding it, or that understanding (and believing) the argument is constitutive of faith.

          > People here are quick to assume that anyone who rejects Aquinas’ proof “doesn’t understand it”.

          It is not always necessary to assume; sometimes, one can just read what they write.

        • jroberts548

          “Well, then he should have said “change” instead of “motion”, no?”

          “Do I really need to state that I already knew that[?]”

          That makes it worse. If you knew better, why were you making an intentionally silly criticism of St. Thomas? Were you being sarcastic? If so, I apologize. Otherwise, don’t make intentionally silly criticisms when you know better.

    • JM1001

      …think of the grave critiques of Hume to the foundations of “cause” concepts, and Kant, and … etc etc …

      If that sentence was written by any freshman philosophy student, it would get an ‘F.’ It’s not even an argument; it’s just an assertion of names (Hume, Kant) without actually engaging in the substance of their arguments and ignoring the many detailed objections to Hume and Kant from classical theists.

      You see a lot of this from atheists — just invoking the names of Hume and Kant, as though their words were final and not subject to criticism. It’s the same mindset you see in fundamentalists — just invoking the Bible, or some sacred text, or a religious founder, etc., without actually engaging the substance of the arguments and their objections.

  • Mark R

    Again, I find Fr. Barron a very cold customer. In the first place, I don’t think St. Thomas formulated his arguments to debate atheism. And using the physical world or the human mind as an analogy for the Almighty, when in reality He is completely Other looks more like intellectual showing off. Nothing important here, like charity or repentance
    Convincing unbelievers? Maybe living charity and martyrdoms will do it.

    • iamlucky13

      A lot of people find formal philosophy cold. That does nothing to diminish its value.

      No, it does not address other important issues, especially charity and repentance. It does not impress people who are kept away from the Christian faith when they don’t see charity or sacrifice among the Christians they know.

      But there is definitely also a huge number of people who are as much or more troubled by what they perceive as a lack of evidence of God and how He reveals Himself to us. To be able to articulate clearly and precisely how we can be rationally confident in our faith, going beyond even trusting the testimony of others (the Bible, etc), much less a more basic superstition I think most atheist perceive Christianity as and some Christians probably even approach their faith as, is a necessary skill for addressing those who reject God on intellectual grounds.

      Also, if Aquinas did not formulate this argument against atheism, than what was it against, and why would you suggest that alternate purpose excludes it from being applied to the question of God’s existence?

    • Greg Brown

      Well, Summa Theologiae was a textbook for Christians, but Summa Contra Gentiles, as the title says, was definitely formulated to debate non-Christians:

      “To proceed against individual errors, however, is a difficult business, and this for two reasons. In the first place, it is difficult because the sacrilegious remarks of individual men who have erred are not so well known to us so that we may use what they say as the basis of proceeding to a refutation of their errors. This is, indeed, the method that the ancient Doctors of the Church used in the refutation of the errors of the Gentiles. For they could know the positions taken by the Gentiles since they themselves had been Gentiles, or at least had lived among the Gentiles and had been instructed in their teaching.

      “In the second place, it is difficult because some of them, such as the Mohammedans and the pagans, do not agree with us in accepting the authority of any Scripture, by which they may be convinced of their error. Thus, against the Jews we are able to argue by means of the Old Testament, while against heretics we are able to argue by means of the New Testament. But the Muslims and the pagans accept neither the one nor the other. We must, therefore, have recourse to the natural reason, to which all men are forced to give their assent. However, it is true, in divine matters the natural reason has its failings.”
      http://dhspriory.org/thomas/ContraGentiles1.htm#2

      He expresses similar remarks in the first Question of Summa Theologiae about the ways that people who lack certain common grounds can engage dialectically.

      Is philosophy cold? Probably, but it doesn’t have to appeal to everyone.

  • catechismhead

    I like the idea that life forms, through adaptation as the evolutionists would tell us, improve their ability thrive, for no particular reason (if there is no God}.