A Variation on the First Way of St. Thomas Aquinas - Part 1

This article was first published in Faith & Reason, 8:1 (Spring 1982),  34-56. Permission to print kindly granted by Christendom Educational Corporation, Christendom College, Front Royal, Virginia, 22630.

Those who would deny the existence of God have long held that St. Thomas’ argument for the necessity of a Prime Mover is refutable on the grounds that things might, after all, be perpetually in motion by nature. This argument has been given new force by materialists who, capitalizing on the claim that entire cosmos is in some sense produced by molecular, atomic and subatomic motion, have seen the atom as a case in point for perpetual motion. In the philosophical analysis which follows, Dennis Bonnette explores the concepts necessary to understand why these claims are inadequate, and how atomic motion actually strengthens the position of Aquinas.

As is well known, St. Thomas Aquinas’ First Way to demonstrate the existence of God proceeds from motion which he describes as “...certain and evident to the senses.”(1) With respect to this proof, the purpose of the present investigation is two-fold: first, to examine the legitimacy of an objection posed against the proof in the name of the Newtonian principle of inertia, and second, to determine whether the very phenomenon which gives rise to that objection may not, in fact, serve as the basis for a somewhat novel approach to the existence of an Infinite Being.

The phenomenon of inertia has been raised as an objection against the First Way by those, such as scientific materialists, who see it as the obvious alternative to a Prime Mover: Things are in motion simply because they have always been in motion. In a challenge flung at the very heart of the First Way, John Hick suggests that:

...it remains possible that some things are just naturally--and conceivably eternally--in motion (in accordance with Newton's first law) without being caused to move at all. Thus the possibility that the physical universe has had no initial state and consists eternally of matter in motion has to be excluded before the first Way can lead anywhere.(2)

What Hick is here talking about is Newton’s principle of inertia with respect to its description of bodies already in motion tending to remain in motion.(3) And it is precisely to avoid this objection that Jacques Maritain moves to safer ground:

Taking the principle of inertia as established, and even hypothetically granting it a meaning beyond the mere empiriological analysis of phenomena, it suffices, in order to reply to the objection, to note that, applied to movement in space, the axiom “Everything which moves is moved by another” ought then logically, by the very fact that motion is considered a state, to be understood as meaning “Every body which undergoes a change in regard to its state of rest or motion changes under the action of another thing.” And thus the axiom remains always true.(4)

When Maritain speaks of “hypothetically granting it (the principle of inertia) a meaning beyond the mere empiriological analysis of phenomena,” he seems to be hinting that his retreat is not really necessary. And it is precisely the ontological analysis of the phenomenon in question which will be the subject of discussion here.(5)

Before engaging in the promised analysis of inertia, it would be well to place the problem posed by inertia back into the context from which it arose, i.e., the question of whether the phenomenon of motion, or change, or coming to be, necessarily implies the existence of an Infinite Being as ultimate Cause of all becoming. In particular, this problem shall be considered from the perspective of the currently prevailing form of atheism itself, namely, scientific materialism. For atheism apparently recognizes the implicit logic of a world whose hallmark is becoming, and precisely to avoid the implications of new being, prefers to deny that anything really new appears in the cosmos.

Atheism evidences its assumption of the principle that from nothing nothing comes to be by the insistence of scientific materialism that the world is eternal -- that there is nothing really new “under the sun.” It maintains that the “atoms” which compose the cosmos are the only real “things” or “substances” and that all that appears to come to be is simply the result of the spatial rearrangement of these submicroscopic cosmic entities.(6) Hence, it claims the phenomenon of change is largely illusory, save for the fundamental relative spatial alterations of “atoms” which alone account for all evolutionary development and “newness.”

Thus, to the modern day atomist, all that is real and comes to be in the cosmos could, in principle, be reduced to the relative motion of two submicroscopic particles in space (even if they be conceived as mathematical points). (7) At least two particles are required since the motion of one particle requires some point of spatial reference which is supplied by the other particle. Thus, in principle, the becoming of the entire cosmos can be reduced to the movement of particle A from point x to point y relative to particle B at point z. And it is precisely this motion of A from x to y relative to B at z which demands explanation -- a motion which in the language of Aristotle would be described as an accidental change in the category of place.(8) (Should one deny this Parmenidean “static” characterization of ultimate units of matter, this would only serve to reinforce the following argument which is based upon the reality of change in the cosmos.)(9)

Now it is not possible to deny the reality of this constant change in spatial relation at the submicroscopic level of being. For scientific materialism has reduced the reality of all change at the macroscopic level of being -- the level of things visible in ordinary experience -- to an explanation in terms of the movement of submicroscopic “atoms.” If the large scale reality is to be explained in terms of submicroscopic reality, then the reality of the submicroscopic change itself cannot be denied without denial as well of the very cosmic evolutionary becoming which atheistic materialism so adamantly defends.

It is precisely at this point that the principle of inertia reappears. For when a cause of the motion of the submicroscopic entities is demanded, the first recourse of positivism is to the eternal momentum of the “atoms.” In fact, Victor Preller goes so far as to misinterpret the First Way of Aquinas in accordance with this very motion of matter in a state of eternal motion. He writes, “The first way generates a temporal regress.”(10) This curious reading of the First Way -- a reading which seems to ignore Aquinas' analogy of the staff which “...does not move except that it is moved by the hand”(ll) -- is bolstered by Preller’s citing a text in which Aquinas speaks of a thrown body:

...the first mover, that is, the thrower, gives to the second mover, that is, air or water or any such body which can naturally move a thrown body, the power to move and to be moved. ...[For] as soon as the first mover, that is the thrower, ceases to move, the air ceases to be moved, but it is still a mover, [italics Preller’s](12)

Of course, today no one would claim that air itself moves physical bodies. Nor is it particularly surprising that the phenomenon of inertia should have proven a bit mystifying to Aquinas at the time of his commentary on Aristotle’s Physics. Nonetheless, a correct reading of the later and more metaphysical text of the Five Ways of the Summa Theologiae reveals clearly that his intent is to describe causality which is operative hic et nunc. Not only do we possess the reference to the “staff” moved by the “hand” in the First Way, but in the Second Way Aquinas tells us explicitly that “...removing the cause removes the effect.”(13)

Even more significantly, when he treats the proof from motion in the corresponding text of the Contra Gentiles, Aquinas states, “The mover and the thing moved must exist simultaneously.”(14) Thus, there can be no doubt but that Aquinas intends, not a temporal regress, but a simultaneous regress among proper causes, in his treatment of the proof from motion.(15) What remains is to show how such an argument retains its validity when confronted by modern objections based upon the phenomenon of inertia. Specifically, what is at issue here is whether, on the one hand, the motion of a body already in a “state” of motion is actually self-explanatory according to the principle of inertia, or whether, on the other hand, such motion yet requires some extrinsic cause as its sole adequate explanation.


Consider again the paradigm described above in which the relative motion of two particles is examined -- even in terms of a constant state of inertia. Note well that two diverse perspectives pertain here: (1) that of the natural scientist and (2) that of the philosopher. To the physicist, the continued motion of particles already in a state of motion is self-explanatory, a perfect instance of Newton's first law of motion. This observation of the modern scientist correctly describes the behavior of the phenomenon in question: a body in motion tends to remain in motion. Nevertheless, precise and correct description of a given phenomenon is not quite the same thing as giving an adequate explanation of why this phenomenon occurs. This is not to challenge the validity of Newton’s insight.(16) Rather, what is being suggested here is that, just as philosophy transcends the perinoetic world of appearances (the proper domain of the natural sciences) in order to penetrate to the dianoetic realm of substantial being itself, so too, it is legitimate in this case to demand the sufficient reason in terms of being for the real and constant change which constitutes the so-called “state” of inertia.(17)

Calling motion a “state” does not render it static. Nor does it lessen the truth that such motion entails the continuous reduction of potency to act -- which reduction, as Aquinas observes, requires a cause because “...nothing can be reduced (from potency) to act except by some being in act.”(18) Maritain’s alteration of “Everything which moves is moved by another,” so as to apply only to changes in states of motion or rest, is quite unnecessary. Even the constant state of motion that is described by the principle of inertia requires a continuous extrinsic cause of such motion.(19)

But what possible cause of motion can be assigned in the model considered above in which the entire cosmos has been reduced in principle to the motion of one particle relative to another? Neither particle can be the cause of the motion: particle A cannot reduce itself from potency to act and particle B is simply taken as a point of reference. Nor, as has been shown above, does the principle of inertia really add to one’s understanding of the cause. Therefore, since the entire cosmos has been reduced, in principle, to the aforementioned elements and since neither of these adequately explains the motion in question, it follows that some cause must be posited which is entirely outside the model representing the universe. It is not necessary at this point to explore the full implications of this initial analysis. But it is important to note here that recourse to the Newtonian principle of inertia will in no way avoid the need for some continuous explanation of the phenomenon of inertia in the cosmos. Moreover, this explanation, whatever it may be, must somehow transcend the universe just as the cause of motion of the particles in the model employed above transcends the particles themselves.

From the foregoing one thing is evident: the phenomenon of inertia of bodies in a state of motion is not self-explanatory. Hence, the models of the cosmos propounded by atheistic materialism which attempt to explain the becoming of the world in terms of matter in a state of eternal motion are flawed at the heart when they rest their case upon the supposedly self-explanatory character of inertia. And having redeemed the First Way from this peculiar presumption of scientific materialism, it might now be well to re-examine cosmic becoming in terms of a model which, rather than being submicroscopic as was the first, is now taken at the super-macroscopic scale of being, i.e., in this instance what shall be considered is the entire physical universe taken all at once -- conceived in all the glory of its dynamic, synergistic, evolutionary character.

What is proposed now is an analysis parallel to that of Zeno's famous paradox of the flying arrow which at a given point in time must be at rest and hence cannot begin to move again.(20) Of course, this analysis will not be based upon the Pythagorean concept of time and space as discrete units -- and it should be noted that, even in the Aristotelian continuum, motion absolutely requires the continuous positing of new aspects of reality in order to explain the process of coming to be.

The illusion of motion is created upon modern motion picture film by the rapid replacement of proximate, but slightly varied, frames of stop motion images -- a succession of images so rapid (24 frames per second) that the human eye records the entire process as a continuum. In the motion picture projector, the key to the rapid succession of images lies in the function of a mechanical shuttle which operates in the film sprocket holes and which actually moves the frames one after another.

What is suggested here is an analogy between this process which produces the illusion of motion and the reality of becoming which is the hallmark of the entire cosmos -- especially in the view of evolutionary materialism. Now the physical world may be said to be limited in the sense that it is expressed in some definite manner at any given time and does not express those states of being which it has not yet attained. Consider, if it were possible, that the entire cosmos would be expressed or represented on but a single frame of film. In order for the continuum of time to move forward (since time is the measure of motion), some new characteristic must come to be in the world. But, whether such a change be of one aspect only or nearly infinite in complexity as the cosmos itself would surely demand, progress in motion would require “getting to the next frame” of the film. How would this be possible? Recourse to inertia has already been ruled out above.(21) And this second model makes even more clear why this is so. For the acquisition of any new “frame” of the universe requires the addition of some characteristic or quality which, in virtue of its “newness,” is lacking in the original “frame.” Since the previous state of the universe is simply, as such, lacking the qualities or aspects of being which distinguish the new state from the previous one, it cannot possibly give to itself those very qualities which are lacking to its limited mode of being.(22) Moreover, since all that which exists in the cosmos has already been included in the frame of film which represents the earlier state of the cosmos, a further obstacle to becoming presents itself in contradistinction to the process in a movie projector. For while the projector has a shuttle which moves the film from one frame to another, the cosmos does not. For the shuttle which moves the film is outside of the frames themselves, whereas in reality everything found within the cosmos has already been included in the consideration of the previous limited state of its being. There is no “external mover” to move it to the next state.

It should now become evident that the notion of a limited cosmos in a process of evolutionary becoming and yet existing solely by itself constitutes a contradiction in terms. Because it is constantly becoming, it needs to acquire new states of reality; because it is limited to its present state of being, it has no source from which to obtain those new states. What this simply means is that, without the tidy “self-explanation” of the principle of inertia, the notion of a universe in a constant state of becoming becomes utterly unintelligible -- provided one restricts one’s explanation to a limited world which, because of its limitation, lacks the very qualities which must come into being in its future states.

Zeno's famous argument against the continued motion of the arrow rested upon the discrete nature of the Pythagorean moment in time; the argument proposed herein works equally well in the Aristotelian continuum. For limitation in being does not depend upon any supposed discrete character in the process of becoming; rather it rests upon the simple fact that, for any change to occur, something new must be posited which was not contained in the earlier state from which it is distinguished as new. The new as such was not contained in the old -- otherwise it would not really be new.

Once again, a physical universe in the process of becoming can be explained only provided one posits the existence of some entity which is entirely other than the universe itself whose each and every part or element is limited by the very space-time continuum in which it manifests its being and acting. Unaided material becoming is a contradiction in being.

Putting the matter at the level of immediate human experience what this all means is, for instance, that one cannot even raise his own hand all by himself. For the very fact that one’s hand is in potency to being raised is equivalent to the fact that one is lacking in the reality-state of having one’s hand actually raised. One cannot give to himself the very quality of existence which is presently lacking -- precisely because it is not in his possession in order to give it to himself. The obvious recourse of scientific materialism at this juncture is to point to the tendons, muscles, nerves, and brain which are supposed to move the hand. But this is to beg the question. For, as Aquinas points out, a cause must be simultaneous with its effect.(23) And as long as the hand is not yet actually raised, it is not raised precisely because these various moving factors are not themselves as yet fully in act, or else, the hand would already be raised. For, how can they begin to move when each of them considered in itself is also lacking in that state of actuality which would constitute its own contribution to the raising of the hand in question?

The common objection that, after all, we possess the “power” to move our limbs ignores the fact that “power” is but another name for the potency to do something and that potency as such is not act. Potency is on the side of non-being -- what is able to be, but is not. The negative character of potency is clearly manifested when one ponders the uncharitable implication of suggesting that someone is potentially quite intelligent.” Potency bespeaks what is not, not what is. The act of having one’s hand raised is precisely what is lacking to someone with his hand not raised -- and all the potency in the world cannot supply for that act which is not actually present. Nor, for that matter, can any other material agent assist in the act of elevation here required unless it too gains some quality of existence which it is presently lacking. This amounts to saying that for someone else to come and raise the subject’s hand presupposes that the would-be assistant can himself overcome the same impediment to the raising of his hand -- for he must raise his own hand in order to raise the hand of the subject.

Note well that what was stated above was simply that one could not raise his own hand all by himself. It was not denied that hands can be raised and frequently are. What is being denied here is that beings which lack a certain state of perfection can give that perfection to themselves. And whether one considers but one single man trying to raise his hand or the entire cosmos in a state of inertial becoming, the inference is the same: things limited to their present state of actuality cannot all by themselves account for their acquisition of new states of actuality. Something else must be posited, i.e., something which already possesses that actuality which is lacking to the unraised hand or even to the present state of the universe taken as a whole. And that something must be other than the previously considered finite components of the analysis.(24)

In light of the foregoing, certain inferences may be drawn -- inferences which will move the plane of this investigation from the merely cosmological to the properly metaphysical. First, it is now evident that a purely physical universe in which motion exists -- nay, in which motion is of the very definition of its nature(25) -- is an entity which cannot be explained in terms of itself alone. Something else must be posited: something non-physical. Second, this non-physical entity (or entities) must constitute the ultimate explanation of all that which comes to be in the physical world, since the entire cosmos is lacking in those new qualities which arise through motion, and therefore, neither can one finite part of the cosmos adequately account for its own motion nor can one finite part adequately account for motion of yet another finite part. Third, the role played by this non-physical entity (or entities) is that of source of all that which comes to be: such being stands as cause to the effect produced. In a word, the eternal evolution of the cosmos assumed by atheistic materialism in order to avoid the existence of some transcendent spiritual cause necessarily implies just such a cause -- not, at this point, necessarily a cause of the very being of the world, but certainly a cause of that being which comes to be -- even if it be only the accidental being of the rearrangement of particles in space as claimed by modern atomists.

One further observation: this spiritual source itself stands entirely outside of time as well as space -- for if it were subject to the form of becoming which is time, the same logic employed above would render it incapable of accounting for its own progress through time and the coming to be entailed therein.

One might well wonder at this point whether the entire above analysis may not encounter a fate which some suggest was encountered by Aristotle in his analysis of motion. That is, having discovered his first unmoved mover in Book VIII of his Physics,(26) he then seems unsure as to the exact number of these prime movers and even raises the question as to whether 47 or 55 of them may exist in Book XII of his Metaphysics!(27) How can the exact number of these spiritual causes of motion be determined? A closer examination of the nature of such a spiritual source as would be required to explain all motion may remedy this perplexity.

A Variation on the First Way of St. Thomas Aquinas - Part 2

© Copyright 2019 Dennis Bonnette, PhD