“Motion is the act of a being in potency insofar as it is in potency.” - Aristotle, Physics Book III, 201a10-11

In his famous First Way of proving God’s existence, St. Thomas Aquinas says, “It is certain, and evident to our senses, that in the world some things are in motion.”¹ But, are things really in motion? Most people would think that motion in the world is too obvious to doubt. Yet, some, based on theories of modern physics, claim that physical change in the universe is actually impossible. Change or motion—meaning that “this” becomes “that” with some persisting reality exhibiting those before and after qualities—simply does not exist. Like Parmenides, those denying motion claim that our dynamically changing, evolving world is merely one grand illusion.

Despite such claims that change is unreal, philosopher of physics Tim Maudlin, well known for studying entangled quantum particles, insists, “Physics has discovered some really strange things about the world, but it has not discovered that change is an illusion.”

In his book, The Trouble with Physics (reprint edition, 2007), theoretical physicist Lee Smolin puts his finger on why physics is prone to make the mistake of saying motion and time are unreal: “…Descartes and Galileo both made a most wonderful discovery: You could draw a graph, with one axis being space and the other being time. A motion through space then becomes a curve on the graph. In this way, time is represented as if it were another dimension of space. Motion is frozen, and a whole history of constant motion and change is presented to us as something static and unchanging.”² In other words, the static mathematical abstractions of modern physics automatically tend to omit the very starting point they presume, namely, the reality of objective motion or change.

In a new book, Neo-Aristotelian Perspectives on Contemporary Science (2017), philosopher Edward Feser points to the incoherence of physicists denying the reality of motion when their scientific method presupposes it. For example, even the simplest experiment requires watching for movement of a needle on a dial:

“When the needle moves from its rest position it loses one attribute and gains another (namely a particular spatial location), and it is one and the same needle that loses and gains these attributes and one and the same dial of which the needle is a component. If there were no gain or loss of attributes, or if the needle or dial were not the same, the observation would be completely useless.”³

Similarly, physicists presume real physical causation takes place through time with ontologically-continuous physical agents causing the continuous coming-to-be of ontologically-continuous effects. For example, the same rocket engine causes the progressive ascent of the same spacecraft into orbit. This is simply how natural science has always understood the nature of physical causation operating in the real world. That a physical theory should be interpreted as contradicting this universal scientific presupposition defies understanding.

Even if change or motion were simply a subjective illusion or a memory function product, it is still immediately recognized and judged by the intellect for precisely what it is, that is, a change. The intellect knows the nature of being and forms a concept of being that begets the universal certitude of the principle of non-contradiction – a truth about reality that scientists absolutely accept, but have no scientific way of explaining. In like fashion, the intellect judges the nature of change or motion as real when immediately experienced – no matter its size or type. Whether it is extramental or intramental change makes no difference. Static experiences alone would never beget the concept of motion, since non-motion contradicts motion.

One of the greatest philosophers of science of the 20^th century, Karl Popper, says of the experience of change within consciousness, “It could not be explained away by a theory of the successive rising into our consciousness of time slices which in some sense coexist; for this kind of ‘rising into consciousness’ would have precisely the same character as that succession of changes which the theory tries to explain away.” Worse yet for materialists who deny change, if all that exists is material, then change’s reality within consciousness means that change is real in the physical universe.

We have a concept of change solely because we have encountered a reality – subjective or not – that actually contained motion. That alone explains how we even have such a concept. Yes, we form concepts of imaginary things. But, they are always composed of elements taken from real objects, as a unicorn is composed of concepts taken from real horses and real horns. Since the concept of change itself is primary, it must be based on an actually existing nature.

Nor could motion or change be experienced as such unless both the “before” and “after” of the change is present to the same knower. This fulfills change’s meaning, since “this” becomes “that” with something (the knower) persisting to both the before and after.

Therefore, change or motion is objectively real.

If some physicists cannot reconcile the immediately given reality of motion or change, as defined here, with their speculative inferences drawn from the special theory of relativity, their speculations must be wrong on that point.

Einstein’s special relativity thought experiment assumes a train moving past a standing observer. Observer, of what? Observer that the train is in motion! The observer knows it is motion because the train he observes is in diverse positions relative to his own position. So, for him there is a before and after with himself, the observer, being present to both – which fulfills the Aristotelian meaning of motion. Clearly, no speculative interpretation of special relativity can contradict the reality of the very motion Einstein’s thought experiment presupposes in its proof.

Either Einstein made a mistake in one of his assumptions, or else, one of several philosophical interpretations of special relativity compatible with motion must be correct.⁴ In any case, the immediately given reality of motion or change trumps any subsequently developed theory that denies its objective reality.

“Quidquid movetur ab alio movetur.” Whatever is moved is moved by another. What this famous principle really means is this: Whatever is in motion is being moved here and now by another. While motion is mostly thought of in terms of local motion – motion from place to place, any type of change can be called motion.

As seen above, motion does not mean simply one thing replacing another, like frames in a motion picture film. Rather, it means one thing becoming somehow different with some persisting reality connecting the before and after. For example, consider the same knower experiencing successive images, or, the same body moving from one position to a different position relative to some point of reference.

Aristotle defines motion as the act of a being in potency insofar as it is in potency. Easier to grasp is this description: the progressive actualization of a potency. For purposes of describing motion, potency is what is able to be, but is not; act is that which is fully real or completed. Strictly speaking, motion means local motion, a change of place. More broadly, it can mean any kind of change, any passage of something from potency to act—sometimes even instantaneously.

For a non-technical macroscopic example, consider water being heated from room temperature to boiling. Motion is not maintaining the water at 72 degrees, but progressively adding heat so as to constantly raise the temperature until 212 degrees is reached. If the “raising” stops at, say, 200 degrees, the motion stops, even though the heat must be maintained to stay at that point. Thus, the motion is not the act already achieved, namely, the 200 degrees, but the act that is achieving the potency yet to be fulfilled, that is, 212 degrees.

The reason everything in motion needs a mover is simple. A thing cannot reduce itself from potency to act and that is exactly what is happening to the thing in motion: it is being reduced from potency to act. Yet, “reduction” here does not mean less being, but more being!

A thing in motion is gaining new perfections of existence every moment it continues to move or change. Since a being cannot give to itself that which it lacks, something else must be giving to it that which it lacks, but is gaining incrementally.

Yet, how do we know this reasoning is correct? While it is easy to defend the principle in terms of the standard Thomistic analysis of potency and act, many today do not fully appreciate the full force of such reasoning.

Here is a different way to see the objective certitude of the principle that whatever is in motion must be being moved by another, one simply based on “the natural metaphysics of human intelligence.”

Everyone knows and uses the metaphysical principle of non-contradiction, that is, that nothing can both be and not be at the same time and in the same way. Even though materialist scientists cannot prove this principle or show how its certitude arises, they have no honest doubts about its universal truth and application. This is because the human intellect, once it forms the concept of being, sees clearly the necessary truth of its application to all possible things.

So too, the fact that you cannot get something from absolutely nothing is universally accepted—after you eliminate claims of getting particles from quantum vacuums that turn out to be something after all. Once it is understood that the philosopher means really nothing, every honest mind assents to the truth that from nothing, nothing comes to be.

What has this to do with things in motion? Simply this: a thing in motion is gaining new properties of being it did not previously possess. As such, with respect to those properties it did not have, it is non-being; nothing at all. Since nothing cannot beget something without extrinsic causal assistance, a being in motion must be getting this new being from something other than itself, that is, from a mover.

For a thing to reduce itself from potency to act would be for it to be giving itself the very perfections of existence that it lacks. This is equivalent to having something that is non-being in a certain respect accounting for the coming-to-be of the selfsame being that it does not have. Being coming from non-being is impossible and absurd.

The full force of this principle is not understood until it is realized that it applies even to bodies already in a “state” of motion—a motion “explained” by most moderns simply by appeal to Newton’s principle of inertia. Even those who defend the principle that motion requires a mover sometimes retreat to applying it solely to cases in which a change in inertial motion occurs. Thus, to accelerate or decelerate an object in motion is seen to require a mover, but that the object merely stays in its present “state” of motion is considered fully explained by inertia.

Part of the problem is that it may not be clear as to exactly which body is in motion, since all motion appears relative—so that if A moves relative to B, we cannot tell which body is actually undergoing the motion. In fact, it could be both. But it really does not matter at all, since all we need to know is that a change of distance or relative position between two or more bodies occurs.

Just as I have shown in a prior Strange Notions article how many confuse physical antecedents with real causes of present effects, so too, acceptance of Newton’s first law of motion as full explanation for the phenomenon of inertial motion causes many to fail to see the further need of metaphysical explanation. Modern science correctly describes the phenomenon under consideration: a body in motion tends to remain in motion. But mere description is not identical to giving an adequate explanation as to why this phenomenon occurs at all.

Calling motion a “state” does not render it static. All motion still requires the continuous reduction of potency to act. And since nothing can give to itself the new perfections or qualities of existence that it lacks, some extrinsic reason or cause must account for the coming-to-be of those changes.

This applies just as much to bodies in a “state” of inertial motion as it does to objects that are accelerating or decelerating. Nor does it matter which object is considered to be in motion, since any change in spatial relation or any other kind of relation between things entails a real change in something—and that requires some extrinsic agent or mover to complete the explanation of what is going on—to account for the “new being” that is manifested, even if that new being is merely a change of relative position. Some outside agent must exist to account for the coming-to-be of the new existential qualities manifested by these new spatial relationships.

Newton’s first law of motion is not an exception to the principle that whatever is in motion requires a mover here and now continuously providing the new modes of existence manifested by continuing change or motion.

Of course, local motion is only one type of motion, but it is one of central occupation to physical science. The principle in question applies to every conceivable type of change, not only of local motion, but also to changes of quality, relation, size, disposition, time, and so forth. It can even be applied to spiritual changes that entail no gradual change. That is, even an instantaneous change by which a potency is actualized requires an extrinsic agent to effect the change, as when a fresh insight suddenly “pops” into one’s mind.

Much more can be said, but this should be enough to demonstrate that the philosophical principle that whatever is in motion is moved by another is absolutely certain and universally true.

This principle is not merely a principle of natural philosophy, but of metaphysics as well—since motion, which is the progressive actualization of a potency, entails that something is gaining new qualities of being. A being in motion must be getting this new being from something other than itself.

All of this shows that this principle is a principle of being, just like the principle of non-contradiction. As such, just like the concept of being and the principle of non-contradiction, it applies to all beings and can be used in an analogical manner, even possibly to reason from finite being to infinite being in a transcendent fashion. This, of course, foreshadows a role for this principle well beyond the topic at hand.

Antony Flew’s famous 1950 article “Theology and Falsification” posed what came to be known as the “falsificationist challenge” to theology. A claim is falsifiable when it is empirically testable—that is to say, when it makes predictions about what will be observed under such-and-such circumstances such that, if the predictions don’t pan out, the claim is thereby shown to be false.

The idea that a genuinely scientific claim must be falsifiable had already been given currency by Karl Popper. Flew’s aim was to apply it to a critique of such theological claims as the thesis that God loves us. No matter what sorts of evil and suffering occur in the world, the theologian does not give up the claim that God loves us. But then, what, in that case, does the claim actually amount to? And why should we accept the claim? Flew’s challenge was to get the theologian to specify exactly what would have to happen in order for the theologian to give up the claim that God loves us, or the claim that God exists.

Now, there are several problems with Flew’s challenge. Some of them have to do with specifically theological matters, such as the analogical use of the term “good” when applied to God, the role that divine permission of evil plays in the realization of a greater good, and so forth. Some of the problems have to do with the idea of falsification itself. As Popper himself emphasized, it is simply an error to suppose that all rationally justifiable claims have to be empirically falsifiable. Popper intended falsificationism merely as a theory about what makes a claim scientific, and not every rationally acceptable claim is or ought to be a scientific claim. Hence not every rationally acceptable claim is or ought to be empirically falsifiable.

For example, the thesis of falsificationism itself is, as Popper realized, not empirically falsifiable. This does not make Popper’s falsificationist theory of science self-refuting, because, again, he does not say in the first place that every claim has to be empirically falsifiable. Falsificationism is a claim about science but it is not itself a scientific claim, but rather a philosophical claim (what Popper called a claim of “meta-science”). It is subject to potential criticism—by way of philosophical analysis and argument, say—but not by way of empirical testing, specifically.

Claims of mathematics and logic are like this too. We can analyze and argue about them philosophically, but they are not plausibly subject to empirical refutation, specifically. And metaphysical claims are like that as well. With at least the most general sorts of metaphysical claims (e.g. about the nature of causality as such, or substance as such, or what have you), it is a sheer category mistake to suppose that they do, or ought to, entail specific empirical predictions. The reason is that the claims are too general for that. They are claims about (among other things) what any possible empirically observable phenomena must necessarily presuppose (and any possible non-empirical realities too, if there are any). Naturally, then, they are not going to be undermined by any specific empirical observation. By no means does that make them immune from rational evaluation. They can still be analyzed, and argued for or against, by way of philosophical analysis and argumentation. But as with claims of meta-science, or claims of mathematics and logic, so too with claims of metaphysics, it is a mistake to suppose that they stand or fall with empirical falsifiability.

Now, the fundamental claims and arguments of theology—for example, the most important arguments for the existence and attributes of God (such as Aquinas’s arguments, or Leibniz’s arguments)—are a species of metaphysical claim. Hence it is simply a category mistake to demand of them, as Flew did, that they be empirically falsifiable. To dismiss theology on falsificationist grounds, one would, to be consistent, also have to dismiss mathematics, logic, meta-science, and metaphysics in general. Which would be, not only absurd, but self-defeating, since the claim that only scientific claims are rationally justifiable is itself not a scientific claim but a metaphysical claim, and any argument for this claim would presuppose standards of logic.

There is also the problem that, as philosophers of science had already begun to see at the time Flew wrote, it turns out that even scientific claims are not as crisply falsifiable as Popper initially thought. Indeed, the problem was known even before Popper’s time, and famously raised by Pierre Duhem. A scientific theory is always tested in conjunction with various assumptions about background conditions obtaining at the time an experiment is performed, assumptions about the experimental set-up itself, and auxiliary scientific hypotheses about the phenomena being studied. If the outcome of an experiment is not as predicted, one could give up the theory being tested, but one might also consider giving up one or more of the auxiliary hypotheses instead, or check to see if the background conditions or experimental set-up were really as one had supposed. That does not mean that scientific theories are not empirically falsifiable after all, but it does mean that falsifying a theory is a much messier and more tentative affair than readers of pop science and pop philosophy books might suppose.

Then there are claims that are empirical and not metaphysical in the strictest sense, but still so extremely general that any possible natural science would have to take them for granted—in which case they are really presuppositions of natural science rather than propositions of natural science. For example, the proposition that change occurs is like this. We know from experience that change occurs, but it is not something falsifiable by experience, because any possible experience by which we might test it itself presupposes that change occurs. In particular, in order to test a proposition via observation or experiment, you need to see whether or not your current experience is followed by the predicted experience, which involves one experience succeeding another, which entails change. Natural science itself, then, which involves attempting to falsify theories (even if it involves more than this) presupposes something which cannot be falsified.

Necessary presuppositions of natural science like the one just described are the subject matter of that branch of philosophy known as the philosophy of nature (which, though more fundamental than natural science, is less fundamental than metaphysics as Thomists understand “metaphysics,” and is thus something of a middle-ground discipline between them). For example, the Aristotelian theory of actuality and potentiality (which is the core of the Aristotelian philosophy of nature) is grounded in an analysis of what change must involve, where the existence of change is presupposed by natural science. Hence the theory of actuality and potentiality is grounded in what is presupposed by natural science. That is why even natural science cannot overthrow it. But the characteristically Aristotelian argument for God’s existence—the argument from change to the existence of an unchanging changer of things (or, more precisely, of a purely actual actualizer of things)—is grounded in the theory of actuality and potentiality, and thus in what natural science itself must take for granted. And thus it too cannot be overturned even by natural science. This “empirical unfalsifiability” is no more a weakness of the Aristotelian argument for God’s existence than the “empirical unfalsifiability” of the existence of change, including the existence of experience itself, is a weakness. It makes the arguments in question (if they are otherwise unproblematic) more rationally secure than empirical science, not less.

Lazy shouts of “unfalisfiability!” against theological claims just ignore all this complexity—the distinctions that have to be drawn between empirical claims on the one hand and claims of mathematics, logic, and metaphysics on the other; between extremely general empirical claims and more specific ones; between philosophy of nature (which studies the philosophical presuppositions of natural science) and natural science itself; and between the testing of a thesis and the testing of the auxiliary assumptions we generally take for granted but conjoin with the thesis when drawing predictions from it.

So, falsificationism is a rather feeble instrument to wield against theology. And in fact, atheist philosophers have known this for decades, even if New Atheist combox commandos are still catching up.

All the same, where we are evaluating a specific empirical claim—rather than a claim of mathematics, logic, or metaphysics, or an extremely general empirical claim like “change occurs”—falsifiability is an important consideration, even if not as decisive as Popper supposed. Take an extremely specific and straightforward empirical claim, e.g. the claim that a large, yellowish triangular shape will suddenly appear in the center of my field of vision within the next few seconds. If no such shape actually appears in the next few seconds, it would be pretty hard to deny that the claim has been falsified. For example, I couldn’t say “Maybe the shape was there in the room, but I didn’t see it because it was behind a bookshelf.” I intentionally phrased the claim so that it was about what I would experience, not about what would be in the room, so appealing to the idea that some physical object stood in the way of my seeing it won’t help avoid falsification. Nor would it help to say “Maybe it will appear an hour from now, or tomorrow,” since the claim referred specifically to the next few seconds.

Of course, that’s not a very interesting empirical claim. Most interesting empirical claims are far less specific than that, even though they are nowhere near as general as the claim that change occurs. There is, needless to say, a large range of cases, some of which are more toward the general end of things, some of them more toward the specific, and the latter are easier to falsify than the former. But even if the more general ones aren’t as crisply falsifiable as a more simplistic application of the Popperian model would imply, they are still far from unfalsifiable.

For example, take the claim that heavy smoking over a long period of time has a strong tendency to cause cancer. Obviously this is not falsified by the fact that some heavy smokers never develop cancer, because the claim has been phrased in a way that takes account of that. It speaks only of a strong tendency, and even a strong tendency needn’t always be realized. But neither is the claim made vacuous by that qualification. If it turned out that only five percent of people who smoke heavily over the course of many years ended up getting cancer, we could reasonably say that the claim had been falsified. Whereas if it turned out that sixty percent of those who smoke heavily over the course of many years end up getting cancer, we would say that the claim had survived falsification, even though sixty percent is well short of one hundred percent. Indeed, even if the percentage were much lower than that—suppose it were forty percent, for example—it would not necessarily follow that the claim had been falsified.

Nor need there be anything like even that strong a link between two phenomena for us reasonably to posit a causal correlation. Take an example often discussed in philosophy of science, viz. the relationship between syphilis and paresis. If syphilis is untreated, it can lead to paresis, though this is rare. But it would be absurd, not to mention medically irresponsible, to conclude that the claim of a causal correlation between syphilis and paresis is falsified by the fact that actually developing paresis is rare. All the same, if there were on record only one or two cases, out of millions, of paresis following upon syphilis, it would—especially if no mechanism by which the one might lead to the other were proposed—be hard in that case to resist the conclusion that the claim of a causal correlation had been falsified.

So, an empirical claim concerning a causal link between two phenomena can be substantive rather than vacuous, and also empirically very well-supported, even if there are many cases in which the one phenomenon is not in fact followed by the other. Considerations about falsifiability, properly understood, do not undermine the point. Indeed, someone who resists such a claim might himself be subject to criticism on the grounds that he has made his position unfalsifiable.

For example, suppose a heavy smoker said, in reply to those who implored him to cut back: “Oh come on, lots of people smoke heavily and don’t get cancer! So how can you maintain your claim that there is a causal link, in the face of all that evidence? Don’t you know that a serious scientific claim should be falsifiable?” In fact, of course, it is the heavy smoker in question who is more plausibly accused of being insufficiently respectful of falsifiability. For there is a very strong link between heavy smoking and cancer, even if the former doesn’t always lead to the latter. And the empirical evidence for that link is so strong that it is those who deny it who are refusing to let their position be falsified by the evidence.

More could be said, but in fact these reflections on falsification are intended merely as a preamble to an application of the idea to a domain very different from the examples considered so far—namely, an example concerning politics and current events. I’ll get to that in another post.
 
 
NOTE: Dr. Feser's contributions at Strange Notions were originally posted on his blog, including this article, and therefore lose some of their context when reprinted here. Dr. Feser explains why that matters.
 
 
(Image credit: Efengshui)