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A tour through Saint Thomas Aquinas’s Summa Contra Gentiles.

July 6, 2014 | 115 Comments

Summary Against Modern Thought: Non-existence Of Infinite Causal Chains

This may be proved in three ways. The first...
This may be proved in three ways. The first…
See the first post in this series for an explanation and guide of our tour of Summa Contra Gentiles.

Previous post.

Here’s what was proved so far: (1) that some things move and others change, and that (2) whatever is in the process of being moved or being changed is being moved or changed by another. Utterly unremarkable assertions; but both the backbone of science, even though some scientists pretend to be skeptical of causality. There is a world, nay a universe, of difference between our knowledge of a cause and of the existence of a cause. Poor Jaki spent his career reminding people of Heisenberg’s fallacy of equivocation. “Poor” because, for whatever reason, people cannot keep in mind the difference between epistemology and ontology. Once more I beg you to read the stone being moved by the stick being moved by the arm being moved by the muscles etc. example. Today we reach the end of the First Way. Next week we begin the Second way.

Chapter 13: Arguments in proof of God’s existence

4 This argument contains two propositions that need to be proved: namely that whatever is in motion is moved by another, and that it is not possible to proceed to infinity in movers and things moved…

11 He proves the other proposition, namely that it is impossible to proceed to infinity in movers and things moved, by three arguments.i

12 The first[10] of these is as follows. If one were to proceed to infinity in movers and things moved, all this infinite number of things would necessarily be bodies, since whatever is moved is divisible and corporeal, as is proved in 6 Phys.[11]ii Now every body that moves through being moved is moved at the same time as it moves.iii Therefore all this infinite number of things are moved at the same time as one of them is moved. But one of them, since it is finite, is moved in a finite time. Therefore all this infinite number of things are moved in a finite time. But this is impossible. Therefore it is impossible to proceed to infinity in movers and things moved.iv

13 That it is impossible for the aforesaid infinite number of things to be moved in a finite time, he proves thus.[12] Mover and moved must needs be simultaneous; and he proves this by induction from each species of movement. But bodies cannot be simultaneous except by continuity or contact. Wherefore since all the aforesaid movers and things moved are bodies, as proved, they must needs be as one movable thing through their continuity or contact. And thus one infinite thing would be moved in a finite time, which is shown to be impossible in 6 Phys.[13]v

14 The second argument[14] in proof of the same statement is as follows. In an ordinate series of movers and things moved, where namely throughout the series one is moved by the other, we must needs find that if the first mover be taken away or cease to move, none of the others will move or be moved: because the first is the cause of movement in all the others. Now if an ordinate series of movers and things moved proceed to infinity, there will be no first mover, but all will be intermediate movers as it were. Therefore it will be impossible for any of them to be moved: and thus nothing in the world will be

15 The third argument[15] amounts to the same, except that it proceeds in the reverse order, namely by beginning from above: and it is as follows. That which moves instrumentally, cannot move unless there be something that moves principally. But if we proceed to infinity in movers and things moved, they will all be like instrumental movers, because they will be alleged to be moved movers, and there will be nothing by way of principal mover. Therefore nothing will be moved.vii

16 We have thus clearly proved both statements which were supposed in the first process of demonstration whereby Aristotle proved the existence of a first immovable mover.viii


iIt is utterly absolutely painfully crucial that you understand what is meant by this. Aquinas means here-and-now, or at-this-very-moment causation. The stick moves the stone here-and-now, your arm moves the stick here-and-now at-this-very-moment, your muscles move your arm here-and-now at-this-very-moment, simultaneously. Your muscle and other cells here-and-now at-this-very-moment move, and so on down to something. Some first unmoved mover. It is this here-and-now at-this-very-moment chain which cannot proceed here-and-now at-this-very-moment to infinity. Update See YOS’s clarification on “instantaneous” movement/change below.

Ed Feser (who not uncoincidentally, since I’ve stolen many of my ideas from him, today wrote on a similar subject) has taken great pains in his many books and articles to teach that this per se chain of here-and-now at-this-very-moment causes exists here-and-now at-this-very-moment, that everything is happening at once. His experience has been that this teaching does not stick. Why? Who knows. But since it is so, I remind you we are not talking about accidental chains of causation, such as when one rock falls off a hill into another, and the second rock then hits a third, and so on. No no no no. We are talking about how movement or change in the here-and-now comes about. Meditate on the example until it is clear in your mind before continuing.

Or watch Feser’s terrific lecture on the subject.

iiAll of Aristotle’s Chapter 6 may be found here. The stick is a body, and so is your arm, and so are your cells, the chemicals, the electrons and neutrons, the quarks, the strings (if they exist) and whatever, if anything, is “below” them. Notice that Aquinas and Aristotle use a proof by contradiction. They assume there exists an infinite here-and-now chain.

iii Here-and-now at-this-very-moment!

ivSweet, no? If there did exist an infinite chain, and because we certainly see things move or change in finite time, this entire infinite chain would have to move not only in finite time, but at this moment, here and now (have we memorized this yet?). The proof immediately follows.

vAristotle proves even more than his: his book 7 may be found here. Anyway, it is clear that if we have an infinite here-and-now chain of objects, the whole thing must itself, here-and-now at-this-moment, move. And that is not possible in finite time. Worse, this would have to be the case for everything everywhere that is in the process of being moved or changed. That’s a lot of chains and lots of infinite movements! Since it is absurd that these infinite chains can move in finite time, yet things are moved or changed in finite time, the chains must not be infinite.

viIf the here-and-now chain is finite—this is an assumption, arguendo—and the first element is removed, the later parts also cannot move, which is obvious. Now I don’t think people understand how big infinity really is. It is not just big, nor even BIG, but horrifically huge. An infinite chain would have more than a googol of elements, which is 10100; it would have more than a googoplex of elements, which is 10googol. If you were to keep doing that operation, namely taking 10 to the power of the last result, and continuing once a second for a whole day, you still would not have got close to infinity. You would still be infinitely far away. But the, to us humans anyway, unimaginably long chain would have only just got started! Just to use your arm to move a stick to push a stone.

An infinite chain is one which never stops. It goes on and on and on and always on some more. If infinite chains existed, there would not and could not be a first element. How, then, would the whole thing get started? Answer: it could not. It would be impossible—not unlikely, but impossible.

I think people believe infinity isn’t all that big because of mathematical analysis, and used in many areas of science. In analysis we regularly and somewhat glibly call on infinity. We say some function converges (perhaps) “O(n2)”, meaning as the number of elements grows, the finite function gets closer and closer to its infinite cousin. We plug in n = 20 or even n = 100 and see that the function is “settling down”, i.e. approaching some obvious value, and we think, “Ah, infinity and n = 100 aren’t that far apart.” However useful an approximation our function at some finite number of elements is, it is never the real value of the function at infinity. Taking approximations as reality and not just as approximations is a common, though not usually painful, fallacy.

It’s a killer here, though. When we are talking movement or change, we cannot have an approximation. We must needs have the whole chain. Stopping at the first (say) 100 elements just won’t do. If we remove a link, the chain cannot pull. And if we do have an infinite chain, there will be nothing to give the chain impetus. Without a first mover, nothing can happen. The chain thus cannot be infinite.

viiThe rock is being moved instrumentally by the stick, which is being moved instrumentally by the arm, and so forth. The principal unmoved mover sets off the whole shebang. I think we get it by now.

viiiLet’s review. We proved the premises in this First Way:

Whatever is in motion is moved by another: and it is clear to the sense that something, the sun for instance, is in motion. Therefore it is set in motion by something else moving it. Now that which moves it is itself either moved or not. If it be not moved, then the point is proved that we must needs postulate an immovable mover: and this we call God. If, however, it be moved, it is moved by another mover. Either, therefore, we must proceed to infinity, or we must come to an immovable mover. But it is not possible to proceed to infinity. Therefore it is necessary to postulate an immovable mover.

The premises being true, and the argument valid, the conclusion must also be true. And therefore it would irrational to deny it. But why God as the unmoved mover? Why not call the immovable mover the Higgs Field Driver or whatever? Well, we haven’t fleshed this part of the proof out yet, so our modern scientistic suspicion is natural.

As a hint—and only a hint—there cannot be more than one immovable mover, one unchangeable changer. There must be something which exists which acts to sustain everything. Stay tuned!

Next installment.

[10] 7 Phys., l.c.
[11] L.c.
[12] 7 Phys. i. ii.
[13] Ch. vii.
[14] 8 Phys. v.
[15] Ibid.

June 29, 2014 | 47 Comments

Summary Against Modern Thought: Potency, Actuality, & Movement

This may be proved in three ways. The first...
This may be proved in three ways. The first…
See the first post in this series for an explanation and guide of our tour of Summa Contra Gentiles.

Previous post.

Last time we only proved one premise, that some things move. Review this first or else you will be lost. This was an observational premise. Of course, some, sensing the coming inescapable conclusion to this argument, suggested with Parmenides that things don’t actually move or change because they only move “relatively”, or whatever. None of these counters are in the least convincing, as we’ll further see. Settle in, we have a lot to do today.

Chapter 13: Arguments in proof of God’s existence

4 This argument contains two propositions that need to be proved: namely that whatever is in motion is moved by another,i and that it is not possible to proceed to infinity in movers and things moved.ii

5 The first of these is proved by the Philosopher in three ways.iii First, thus. If a thing moves itself, it must needs have the principle of its movement in itself, else it would clearly be moved by another.iv Again it must be moved primarily, that is, it must be moved by reason of itself and not by reason of its part, as an animal is moved by the movement of its foot, for in the latter way not the whole but the part would be moved by itself, and one part by another. Again it must be divisible and have parts, since whatever is moved is divisible, as is proved in 6 Phys.[2]v

6 These things being supposed, he argues as follows. That which is stated to be moved by itself is moved primarily. Therefore if one of its parts is at rest, it follows that the whole is at rest. For if, while one part is at rest, another of its parts were in motion, the whole itself would not be moved primarily, but its part which is in motion while another is at rest. Now nothing that is at rest while another is at rest, is moved by itself: for that which is at rest as a result of another thing being at rest must needs be in motion as a result of the other’s motion, and hence it is not moved by itself. Hence that which was stated to be moved by itself, is not moved by itself. Therefore whatever is in motion must needs be moved by

7 Nor is this argument traversed by the statement that might be made, that supposing a thing moves itself, it is impossible for a part thereof to be at rest, or again by the statement that to be at rest or in motion does not belong to a part except accidentally, as Avicenna quibbles.[3] Because the force of the argument lies in this, that if a thing moves itself primarily and of itself, not by reason of its parts, it follows that its being moved does not depend on some thing; whereas with a divisible thing, being moved, like being, depends on its parts, so that it cannot move itself primarily and of itself.vii Therefore the truth of the conclusion drawn does not require that we suppose as an absolute truth that a part of that which moves itself is at rest, but that this conditional statement be true that if a part were at rest, the whole would be at rest. Which statement can be true even if the antecedent be false, even as this conditional proposition is true: If a man is an ass he is irrational.viii

8 Secondly,[4] he proves it by induction, thus. A thing is not moved by itself if it is moved accidentally, since its motion is occasioned by the motion of something else. Nor again if it is moved by force, as is manifest.ix Nor if it is moved by its nature like those things whose movement proceeds from themselves, such as animals, which clearly are moved by their souls.x Nor if it is moved by nature, as heavy and light things are, since these are moved by their generating cause and by that which removes the obstacle to their movement.xi Now whatsoever things are in motion are moved either per sexii or accidentally; and if per se, either by force or by nature: and if the latter, either by something in them, as in the case of animals, or not by something in them, as in the case of heavy and light bodies. Therefore whatever is in motion is moved by another.

9 Thirdly,[5] he proves his point thus. Nothing is at the same time in act and in potentiality in respect of the same thing. Now whatever is in motion, as such, is in potentiality, because motion is the act of that which is in potentiality, as such.[6] Whereas whatever moves, as such, is in act, for nothing acts except in so far as it is in act. Therefore nothing is both mover and moved in respect of the same movement. Hence nothing moves itself.xiii

10 We must observe, however, that Plato,[7] who asserted that every mover is moved, employed the term movement in a more general sense than Aristotle. For Aristotle took movement in its strict sense, for the act of a thing that is in potentiality as such, in which sense it applies only to divisible things and bodies, as is proved in 6 Phys.[8] Whereas according to Plato that which moves itself is not a body; for he took movement for any operation, so that to understand or to think is a kind of movement, to which manner of speaking Aristotle alludes in 3 De Anima.[9] In this sense, then, he said that the first mover moves itself, in as much as it understands, desires and loves itself. This, in a certain respect, is not in contradiction with the arguments of Aristotle; for it makes no difference whether with Plato we come to a first mover that moves itself, or with Aristotle to something first which is altogether immovable.xiv


iYou, dear reader, are potentially in Cleveland. Unless you’re not actually there, you are not actually there, but you potentially could be. Right? Now what could bring you there? Well, many things. A car, your feet, a plane. Unless you are dead, there is no logically necessary reason you couldn’t (sometime) be there. Point is this: if you are now here and later in Cleveland, some actual thing or things caused you to be there. It could not have been the potential of you being in Cleveland that caused you to be there.

In front of us is a blank canvas. It is potentially a painting of a horse. If it becomes such, some actual thing caused it to be. That it was potentially a picture of a horse could not be the cause. That is, the potential is not and cannot be a cause. Some actual thing or things was the cause.

A block of wood that is here may potentially be there, but to get there some actual thing must cause it to move. The potential that is there cannot be a cause. And so on.

We need these observations for background.

iiOnly the first premise today. This premise is handled later. As promised, slow going.

iiiWe only do this first proof today.

ivAn animal can move itself, as the next premise demonstrates. But pay attention to what it means when an animal moves itself. A rock, for instance, or a molecule of oxygen in the atmosphere must be moved by something actual.

vHere is Aristotle on this crucial subject (from Aquinas’s footnote):

Further, everything that changes must be divisible. For since every change is from something to something, and when a thing is at the goal of its change it is no longer changing, and when both it itself and all its parts are at the starting-point of its change it is not changing (for that which is in whole and in part in an unvarying condition is not in a state of change); it follows, therefore, that part of that which is changing must be at the starting-point and part at the goal: for as a whole it cannot be in both or in neither. (Here by ‘goal of change’ I mean that which comes first in the process of change: e.g. in a process of change from white the goal in question will be grey, not black: for it is not necessary that that that which is changing should be at either of the extremes.) It is evident, therefore, that everything that changes must be divisible.

Thus divisible also means extended in space. Even photons, which haven’t any mass, are extended waves. They are not particles of no, or absolutely zero, size.

viIn other words, in those creatures capable of self-locomotion parts of them are being moved by other parts, as when you walk. Do not forget we are interested in the parts which are moving themselves, and how and why they move. Re-read the example given in the previous post. This is absolutely necessary to understand. We are at stick-moving-the-stone example, where your arm is moved by muscles are moved by cells are moved by chemicals are moved by individual atoms are moved by electrons and protons are moved by quarks are moved by strings (or whatever) are moved, ultimately, by an unmoved (and unmovable) mover all now, at this instant.

viiWhat might “a thing moves itself primarily and of itself, not by reason of its parts” mean? If a thing could move itself not by its parts, but primarily, it would be like—and this is a weak and fictional analogy—a psychic remaining still and concentrating his mental “powers” so that his body flies through the air. But of course, that would still involve the movement many physical things (physical forces must come into play to interact with the body to shift it) and of the mental powers themselves, from a quiescent to active state, so it doesn’t ultimately work (see below). The point Aquinas is saying is that nothing can move primarily. Something must set off (and sustain) every motion or change. And, as above, this something must be something actual and not potential.

viiiZing! Ha ha ha! The great man himself with a hilarious pun.

ixThese are self-evident.

xThomas does not mean to invoke the psychic example, but by soul he means, if you like, by consciousness. Anyway, if the soul moves its object, then another has moved that object.

xiThat this premise is outdated doesn’t change the proof. A light thing is moved by (say) the wind, and not primarily; or it is moved accidentally or by a force, etc.

xiiPer se, i.e. by virtue of itself; accidentally, here by one part pushing another, or the whole being pushed by something exterior, as in you in a TSA groping line at the airport.

xiiiIf you are moving from A to B, it is only because you are potentially in or at B that you can move. If it is impossible—and not just unlikely, however unlikely—then you are not potentially in or at B. And since potentiality cannot be a cause, it must be act, or something actual, which is driving the movement. The key to this argument is “Therefore nothing is both mover and moved in respect of the same movement.” Understand that, and you have it made. All three parts are necessary: the mover, that which is moved, and this here and now movement.

xivIsn’t that pretty? Exciting, too, because our task is not only to prove God’s existence, but, having done so, to show what we can about God’s nature. This is a kind of first step in that direction. Here, don’t forget that Aristotle and Plato do not mean just physical movement from A to B, but change of any kind; Plato includes changes in, if you like, thinking, or willing; Aristotle does not. The psychic analogy might be welcomed by Plato but not Aristotle. Our intellects are not material, and therefore not divisible or extended.

Again, it is an act which must change something in A but which is potentially in B to B. It will turn out that God is, in Aristotle’s and Thomas’s terms, pure act or actuality itself, with no potentiality (this was not proved today). This is another reason to thoroughly grasp the difference between act and potential. We’ve only done a bare outline. For the terrific introduction in modern language, see Ed Feser’s new Scholastic Metaphysics: A Contemporary Introduction. Note: I’ll be reviewing this book soon.

All that was proved today was whatever is in motion is moved by another. Every scientist accepts this premise. In this sense, today’s arguments were scientific proof. This premise is something upon which all science relies. Its implications are, of course, deeper than science, but it encompasses the motivating force behind science. No scientist says, “This went/changed from A to B for no reason whatsoever.”

Don’t forget we have one more premise in the first way (of proof of God’s existence). Then we have a whole second way.

[2] [Physics] Ch. iv.

[3] 2 Suffic. i.

[4] 8 Phys. iv

[5] 8 Phys. v. 8.

[6] 3 Phys. i. 6.

[7] Phoedrus xxiv. (D.).

[8] L.c.

[9] Ch. vii.

June 15, 2014 | 91 Comments

Summary Against Modern Thought: First Steps In The Scientific Proof Of God

This may be proved in three ways. The first...
This may be proved in three ways. The first…
See the first post in this series for an explanation and guide of our tour of Summa Contra Gentiles.

Previous post.

We have reached at long last the happiest part of our journey. A proof for the existence of God. Aquinas starts and ends with the best, an argument which, once it is understood, grasped at its full, is fully convincing. It is a scientific proof. It is based on the indisputable evidence of our long observation of Nature. It first saw print, as so much foundational knowledge has does, with Aristotle. So strongly does Aquinas feel about this argument that he offers no other in this work. It is an argument, or rather two arguments which share much in common, which he, and which I think you will agree, is best suited for those of a scientific mind. Read all three (short) paragraphs from Aquinas before reading the footnotes.

Chapter 13: Arguments in proof of God’s existence

1 HAVING shown then that it is not futile to endeavour to prove the existence of God, we may proceed to set forth the reasons whereby both philosophers and Catholic doctors have proved that there is a God.

2 In the first place we shall give the arguments by which Aristotle sets out to prove God’s existence: and he aims at proving this from the point of view of movement, in two ways.i

3 The first way is as follows.[1] Whatever is in motion is moved by another: and it is clear to the sense that something, the sun for instance, is in motion.ii Therefore it is set in motion by something else moving it. Now that which moves it is itself either moved or not. If it be not moved, then the point is proved that we must needs postulate an immovable mover: and this we call God. If, however, it be moved, it is moved by another mover. Either, therefore, we must proceed to infinity, or we must come to an immovable mover. But it is not possible to proceed to infinity. Therefore it is necessary to postulate an immovable mover.iii

4 This argument contains two propositions that need to be proved: namely that whatever is in motion is moved by another, and that it is not possible to proceed to infinity in movers and things moved.iv


iThere are various kinds of movement, change, or evolution that first must be understood. There is movement in space, where an object is first here then there, or a change in orientation. There can be change in mass, where an object excretes or accretes. There can be change in energy, such as when a field offers up a newly created particle from a “quantum fluctuation,” or when mass is converted to energy. There can be change in qualitative characteristics, such as in color. In short, any differentiation whatsoever in an object can be considered change or motion. There need not be, of course, any person to witness or measure this differentiation, nor do we need to understand all of the (secondary efficient) causes that bring this differentiation about. Somebody with no knowledge of internal combustion engines is surely aware that a car moves from one place to another.

iiFor bookkeeping, and for commenting, label the first argument “W1”, for “Way 1”, etc.

We begin with the observation that things move, that they change. There can be no doubt about this. Even those who profess complete philosophical skepticism know that their minds change (about objects moving). (I say “profess” because however much somebody might claim to be a skeptic, nobody except possibly the genuinely insane actually believes it. If you argue with me, you necessarily agree with me. But this point is not in the least necessary for us to continue. Feel free to pretend your computer is not really there.)

And what around us does not change? All of Nature, i.e. the physical, does. Trees rot, even protons decay, babies are born, the universe expands. What remains motionless? Well, truth. Mathematical truths are not subject to movement, neither can logical truths shift from place to place or grow hair. Our knowledge of such truths, individually and collectively, surely evolves, or devolves, as the case may be. But the truths themselves are incorruptible. Again, if you disagree, you agree. If you say, “All truths are inventions”, you have either stated a truth or an invention. If it is a truth, your proposition is self-defeating. If it is an invention, there is no reason to trust it. There is no way to speak coherently except by admitting truth exists and is unchangeable.

Anyway, that much is background. Aquinas is not claiming nothing is unchangeable. His first simple indubitable plain commonsensical premise is only that some things move, and that we all see this to be the case, as for example the relative motion of the sun or your finger on the scroll bar. This is all you must advert to now. Do you?

iiiNow W1 will be proved bit by bit. Aquinas will give examples and clarifications of each of the propositions and premises which comprise the argument and when he is finished no loose ends will remain. However, it is well here to ensure you grasp the intention or meaning of this argument before continuing. Here is a sketch.

Take an analogy—an analogy, I say—from Fulton Sheen. You see a boxcar of a train pass by. It moves. Something caused it to move. What? Well, the boxcar in front of it pulls it. But what caused that boxcar to move? The one in front of it. But this cannot go on forever. We cannot have an infinity of boxcars, each pulled by the one in front. At the start of the line there must exist an engine which pulls all along, or there can be no movement.

The same analogy holds for cogs in a machine. This one moves by the one before it, and so on, a series which must terminate at an axle hooked to a motor. There must be a start.

These are only analogies because we left off short. Something is causing the engine to move, and something is causing the motor to spin. These causes are operating now, in this moment. And this what we’re talking about. Movement or change occurring the here in the right now, at this instant.

The classic example is a stick pushing a stone. Imagine yourself holding the stick and applying steady pressure to it, nudging the stone. The stone moves because of the stick. The stone moves now, in this moment because of the stick’s pressure. The stick is also in motion: it has force now, in this moment applied to it via your arm. Your arm is also in motion: its muscles contract or extend now, in this moment. This is happening all at once, at the same instant. Do not let this slip from your mind.

The muscles are also in motion: individual cells contract or extend now, in this moment. The materials in the cell are also in motion: chemicals are moving or reacting now, in this moment. The chemicals are also in motion: the chemicals subcomponents are moving or reacting now, in this moment; and if the chemicals are simple, the electrons in its shell and the neutrons and protons in its nucleus are moving now, in this moment. And the electrons themselves, and the quarks inside the nucleus are moving now, in this moment.

Again, all this is happening at once. Not in the distant past, but right now.

The quarks are also in motion: the strings, or whatever, inside the quarks now, in this moment are also “vibrating”.

Are there things “bellow” strings, or whatever? I don’t know. It doesn’t matter. What does is that if there is, whatever these objects are, have to be in motion now, in this moment too. The chain of all these objects pushes along, as it were, pushed from “below,” all at the same time. This series cannot, however, continue to infinity. There cannot an infinite number of things smaller, or rather more base, than strings and which must first move before any movement is possible.

There must be a base. There must be a thing which moves, which is itself not moved, and is indeed immovable. There must be a start to everything, a first unmoving mover. If there were not, nothing would ever happen. And we have already agreed things happen.

Now two happy things follow from this. The first (and the proof of this is coming: this is not here a proof, but a claim: do not say it was not proved when it is not claimed as being proved) is that this unmoved mover is and must be the same everywhere and for all changes. That is why the unmoved mover is God.

The second is that to be truly scientific, to honestly understand physics, to speak properly of causation and how the universe is run, one must understand God. Because He is there, at base, in everything. He is the root cause of every single thing that happens. This should be cheering, not the least because of the good news we have received some two thousand years ago, but because our task of contemplating the world is proven finite. There must come a point below which physics ends and God begins, to speak loosely. It is not clear if we will ever figure out the whole of mechanics, though. All we have proved is that the causal movement-chain must be finite. We haven’t any idea, through arguments of this kind, how long it is. Finite does not imply short.

ivCall these P1 and P2, or properly W1P1, etc. Next time we start with these same premises. They are given here for the sole reason of noting that there was only one thing proved in this post. That we see some things move. Everything else was a clarification, a heads up. The argument for God being the unmoved Mover was merely sketched. There is thus no point whatsoever in claiming that the main argument was found wanting because it hasn’t yet been fully given.

Clever readers will also have recognized that at no point was scripture invoked. No divine revelation, other than the ordinary kind, i.e. the revelations of our senses, is assumed. Like I said up top, this proof is purely scientific.

Next installment.

[1] 7 Phys. i.

June 8, 2014 | 68 Comments

Summary Against Modern Thought: How Through Reason We’ll Prove God’s Existence

This may be proved in three ways. The first...
This may be proved in three ways. The first…
See the first post in this series for an explanation and guide of our tour of Summa Contra Gentiles.

This is the last of the necessary but, it must be admitted, less-than-riveting introductory posts. It must be kept in mind that Summa Contra Gentiles is primarily a Teacher’s Guide and not per se a text for students. We’re adapting it as we go. Next week we launch into the good stuff, the first proofs for the existence of God. We’ve sped up to get here, but next week we reduce pace dramatically since to progress we need material Aquinas assumes but which we Moderns have largely forgotten.

Chapter 8: In what relation human reason stands to the truth of faith

(1) IT would also seem well to observe that sensible things from which human reason derives the source of its knowledge, retain a certain trace of likeness to God, but so imperfect that it proves altogether inadequate to manifest the substance itself of God. For effects resemble their causes according to their own mode, since like action proceeds from like agent; and yet the effect does not always reach to a perfect likeness to the agent…i

Chapter 9: Of the order and mode of procedure in this work

(2) Wherefore in order to deduce the first kind of truth we must proceed by demonstrative arguments whereby we can convince our adversaries. But since such arguments are not available in support of the second kind of truth, our intention must be not to convince our opponent by our arguments, but to solve the arguments which he brings against the truth, because, as shown above,[1] natural reason cannot be opposed to the truth of faith.ii

In a special way may the opponent of this kind of truth be convinced by the authority of Scripture confirmed by God with miracles: since we believe not what is above human reason save because God has revealed it. In support, however, of this kind of truth, certain probable arguments must be adduced for the practice and help of the faithful, but not for the conviction of our opponents, because the very insufficiency of these arguments would rather confirm them in their error, if they thought that we assented to the truth of faith on account of such weak reasonings.iii

(3) …we shall first of all endeavour to declare that truth which is the object of faith’s confession and of reason’s researches, by adducing arguments both demonstrative and probable, some of which we have gathered from the writings of the philosophers and of holy men, so as thereby to confirm the truth and convince our opponents…

(4) Seeing then that we intend by the way of reason to pursue those things about God which human reason is able to investigate, the first object that offers itself to our consideration consists in those things which pertain to God in Himself…Of those things which we need to consider about God in Himself, we must give the first place (this being the necessary foundation of the whole of this work), to the question of demonstrating that there is a God: for unless this be established, all questions about divine things are out of court.iv

Chapter 10: Of the opinion of those who aver that it cannot be demonstrated that there is a God, since this is self-evident

(1) POSSIBLY it will seem to some that it is useless to endeavour to show that there is a God: they say that it is self-evident that God is, so that it is impossible to think the contrary, and thus it cannot be demonstrated that there is a Godv

(2) Those things are said to be self-evident which are known as soon as the terms are known: thus as soon as it is known what is a whole, and what is a part, it is known that the whole is greater than its part…

Chapter 11: Refutation of the foregoing opinion and solution of the aforesaid arguments

(5)…For just as it is self-evident to us that a whole is greater than its part, so is it most evident to those who see the very essence of God that God exists, since His essence is His existence. But because we are unable to see His essence, we come to know His existence not in Himself but in His effectsvi

Chapter 12: Of the opinion of those who say that the existence of God cannot be proved, and that it is held by faith alone

(1) THE position that we have taken is also assailed by the opinion of certain others, whereby the efforts of those who endeavour to prove that there is a God would again be rendered futile. For they say that it is impossible by means of the reason to discover that God exists, and that this knowledge is acquired solely by means of faith and revelationvii

(5) [Another potential counterargument.] If the principles of demonstration become known to us originally through the senses, as is proved in the Posterior Analytics,[3] those things which transcend all sense and sensible objects are seemingly indemonstrable. Now such is the existence of God. Therefore [opponents say] it cannot be demonstrated…

(9) It is also evident from the fact that, although God transcends all sensibles and senses, His effects from which we take the proof that God exists, are sensible objects. Hence our knowledge, even of things which transcend the senses, originates from the senses.viii


iWe made this point before, but you watching a man crush an aluminum can would not allow you to infer his complete strength, neither would following him solve “2 + 7” allow you to plumb his intellectual depths. Neither can we look out into the world and learn all about God. However, that you see a man crush a man indicates that there is a man crushing the can, and that you see a man solve an equation proves there is an existing intellect.

iiAs promised, nothing but logical proof for our fundamental claims. No revelations drawn upon. All unbelievers can play. But if somebody makes a claim against Scripture, Aquinas is ready to defend.

iiiWe wouldn’t want our adversaries thinking we believe in flying spaghetti monsters simply because we wanted to believe. Indeed, the pasta sauce will soon be on the other foot. Opponents are going to have to work very hard indeed to counter the arguments which are coming. Be warned that they stood for roughly two-and-a-half millennia. Your task won’t be easy; in fact, it will be impossible.

ivWe are all in agreement here, I hope and pray.

vWhat follows here and in Chapter 11 is St Anselm’s so-called ontological argument and a refutation of the same and two other similar arguments. That God is self-evident and not in need of proof is not a problem for moderns in the least. Consequently, as interesting as Thomas’s arguments are on this matter, we pass on quickly.

viWe cannot know God as He is in himself. Most of us can barely remember what we had for lunch last Tuesday, let alone grasp the Infinite. Aquinas is not trying to slip in an Intelligent Design (as moderns know the term) argument. And he was most certainly not a Creationist in any sense beyond believing that God was—and is, even at this moment—the cause of the universe (for the universe had to and must currently have a cause, as we’ll see).

viiThis has become a slur in our time. Only fools believe by faith. The intelligent know by science. Of course, this sad formula ignores that many things must be taken on faith or reason goes nowhere. We have discussed axioms as a primary instance. But never mind all that. This is our last warning, one I predict which will be forgotten in the weeks to come, that our proofs are fundamental and require the exact same amount of faith that any mathematician or physicist brings to his tasks.

viiiJust as in mathematics we know of infinity, and its various flavors and sizes, but cannot savor these flavors nor comprehend these sizes, so can we prove (and will) certain things about God’s nature. For instance, we can say He is Omnipotent, and even define the broad outlines of this quality, but moving from that to knowing just what’s on God’s mind? You can’t get there from here, not using unaided the weak powers of the human mind.

But enough! We are at this point in the position of children rankling under the forced repetition of scales, anxious to move to our first melody. It is a sweet tune, our starting one. Aristotle started humming it a long time ago and it hasn’t lost any of its vigor or shine by repetition. To continue this silly metaphor, it’s a song that once you hear it you can’t get out of your head. Nor will you want to.

[1] Ch. vii.
[3] 2 Poster. ix. i., xviii. [Aristotle]

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