Just for reference...

StMichael's picture

Here they are, straight outa 'da Summa Theologica of the Angelic Doctor:

I answer that, The existence of God can be proved in five ways.

The first and more manifest way is the argument from motion. It is certain, and evident to our senses, that in the world some things are in motion. Now whatever is in motion is put in motion by another, for nothing can be in motion except it is in potentiality to that towards which it is in motion; whereas a thing moves inasmuch as it is in act. For motion is nothing else than the reduction of something from potentiality to actuality. But nothing can be reduced from potentiality to actuality, except by something in a state of actuality. Thus that which is actually hot, as fire, makes wood, which is potentially hot, to be actually hot, and thereby moves and changes it. Now it is not possible that the same thing should be at once in actuality and potentiality in the same respect, but only in different respects. For what is actually hot cannot simultaneously be potentially hot; but it is simultaneously potentially cold. It is therefore impossible that in the same respect and in the same way a thing should be both mover and moved, i.e. that it should move itself. Therefore, whatever is in motion must be put in motion by another. If that by which it is put in motion be itself put in motion, then this also must needs be put in motion by another, and that by another again. But this cannot go on to infinity, because then there would be no first mover, and, consequently, no other mover; seeing that subsequent movers move only inasmuch as they are put in motion by the first mover; as the staff moves only because it is put in motion by the hand. Therefore it is necessary to arrive at a first mover, put in motion by no other; and this everyone understands to be God.

The second way is from the nature of the efficient cause. In the world of sense we find there is an order of efficient causes. There is no case known (neither is it, indeed, possible) in which a thing is found to be the efficient cause of itself; for so it would be prior to itself, which is impossible. Now in efficient causes it is not possible to go on to infinity, because in all efficient causes following in order, the first is the cause of the intermediate cause, and the intermediate is the cause of the ultimate cause, whether the intermediate cause be several, or only one. Now to take away the cause is to take away the effect. Therefore, if there be no first cause among efficient causes, there will be no ultimate, nor any intermediate cause. But if in efficient causes it is possible to go on to infinity, there will be no first efficient cause, neither will there be an ultimate effect, nor any intermediate efficient causes; all of which is plainly false. Therefore it is necessary to admit a first efficient cause, to which everyone gives the name of God.

The third way is taken from possibility and necessity, and runs thus. We find in nature things that are possible to be and not to be, since they are found to be generated, and to corrupt, and consequently, they are possible to be and not to be. But it is impossible for these always to exist, for that which is possible not to be at some time is not. Therefore, if everything is possible not to be, then at one time there could have been nothing in existence. Now if this were true, even now there would be nothing in existence, because that which does not exist only begins to exist by something already existing. Therefore, if at one time nothing was in existence, it would have been impossible for anything to have begun to exist; and thus even now nothing would be in existence---which is absurd. Therefore, not all beings are merely possible, but there must exist something the existence of which is necessary. But every necessary thing either has its necessity caused by another, or not. Now it is impossible to go on to infinity in necessary things which have their necessity caused by another, as has been already proved in regard to efficient causes. Therefore we cannot but postulate the existence of some being having of itself its own necessity, and not receiving it from another, but rather causing in others their necessity. This all men speak of as God.

The fourth way is taken from the gradation to be found in things. Among beings there are some more and some less good, true, noble and the like. But "more" and "less" are predicated of different things, according as they resemble in their different ways something which is the maximum, as a thing is said to be hotter according as it more nearly resembles that which is hottest; so that there is something which is truest, something best, something noblest and, consequently, something which is uttermost being; for those things that are greatest in truth are greatest in being, as it is written in Metaph. ii. Now the maximum in any genus is the cause of all in that genus; as fire, which is the maximum heat, is the cause of all hot things. Therefore there must also be something which is to all beings the cause of their being, goodness, and every other perfection; and this we call God.

The fifth way is taken from the governance of the world. We see that things which lack intelligence, such as natural bodies, act for an end, and this is evident from their acting always, or nearly always, in the same way, so as to obtain the best result. Hence it is plain that not fortuitously, but designedly, do they achieve their end. Now whatever lacks intelligence cannot move towards an end, unless it be directed by some being endowed with knowledge and intelligence; as the arrow is shot to its mark by the archer. Therefore some intelligent being exists by whom all natural things are directed to their end; and this being we call God.

Psalm 50(1):8. For behold thou hast loved truth: the uncertain and hidden things of thy wisdom thou hast made manifest to me.


  1. What put God into motion?  Since your argument depends on the postulation that everything in motion must have been placed into motion, obviously something must have placed God into motion, or your premise is incorrect, and God is no longer the necessary solution.
  2. Once again, this argument defeats itself.  If everything must have a cause, what is the cause of God?
  3. And a third time.  If your case depends on the absolute definition that nothing can exist without a creator (except God), by adding an exception, you nullify the argument.  You can't say that since nothing can cause itself, then God, who has no cause, must be the cause of all things, including himself.
  4. What is the maximum heat?  The allegory you give is that all things which are relative are relative only to the absolute.  Although an absolute cold exists, what is the absolute heat?  If heat can exist without an absolute heat, than "goodness" can exist without an absolute good by your argument.
  5. Although it is true that incredible complexity exists in the world, it is also true that many "designs" are very ill-fitted towards existance.  The entire concept of aging, disease, and the fact that the human body cannot reliably inhabit the planet without dying of exposure.  The arrow being shot at the mark is one thing, but the branch falling from the tree is another.  Both have a destination, but only one is specifically designed for a purpose.


There are two basic flaws in all 5 premises.  All five infer that nothing in the universe can exist without something to spur it to exist.  Then, it makes the assumption that that which spurs existance needs no spurring of its own.  That is a serious flaw.  It is a non sequitor, stating that the disproof of the premise is the proof of the conclusion.

 The second flaw is that proof of some designing force or governing force automatically assumes an anthropomorphic force.  Even if these arguments were to prove the existance of a designer, which they do not, what is your proof that this designer has any qualities other that of simply causing the universe to exist?

StMichael's picture

I am currently discussing

I am currently discussing these proofs in other forums. However, in specific response:

  1. God does not have to be put into motion. The reason you say this is because of a fundamental misunderstanding of the argument. Read it again. It does not say, "everything needs a mover" or "everything needs a cause." Rather, it says that all things which are in motion are put in motion by a mover. Thus, one unmoved mover is necessary.
  2. As above.
  3. It is not an argument that nothing exists without a creator. It is an argument that things in the world are obviously possible existences - the car does not necessarily exist, as it was made at one point in time and could be destroyed tomorrow. All possible things depend on a necessary existence. Ultimately, there must be an absolutely necessary being which provides all being to all other things. This is God. God does not cause Himself, He is the source of existence.
  4. Another problem in misunderstanding the proof. Let's work the other way around. In the world, we notice that there are certain beings reducible to other beings, in a definite graded order. For example, we see that the accidents of a thing depend on what it is, and that an dependent being must rely on a necessary being for its existence. All beings are thus reducible to their principles in a certain graded order. And since the principle of the being of all things must be being in the highest degree, these principles must be most perfect and supremely in act. The most supreme principle of all things, subsistent existence itself, is God.
    Further, specifically in response, absolute heat does exist. The heat itself as the cause of heat in other things is maximum heat. In a similar way, goodness itself holds the highest place in the genus of good things.
  5. The notion of the tending of things to ends that work for the best is easily apparent around us. For example, maximum entropy production is an easily observable phemonenon where entropy dissipates on the most effective path. Or, another is where chemical reactions tend by nature to the most stable state. I don't see what the human body has to do with it. Evolution would be another proof, as many things that do not have intelligence proceed according to an orderly design that works out for the best functioning of the species. These are clear orderings of ends so that things work out for the best all or almost all of the time.

On the first general objection, I think it is entirely logically clear that something cannot come from nothing. I know, I know, but physics demonstrates that things can spontaneously arise in certain conditions. But this is not something coming from nothing. It is a particle, for example, arising out of the fabric of space/time. It is something coming from something. The principle that something cannot exist and not exist in the same regard is a principle of logic, and is fundamental to its existence.

On the other hand, you speak of this as that everything needs a cause for its existence, which is not true. I never claimed this, ever. Only that which dependent on other causes needs a cause. So, for example, a thing in motion needs a mover. A thing caused in an order of efficent causes needs a cause. A thing which is a dependent being needs a necessary being. At least one necessary, unmoved, and uncaused being must exist. This is all that is claimed.

On the second consideration, it is not yet assumed that this cause is intelligent or all-knowing, ect. We would call such God, but we have not yet explicated what properties such a being would possess. We cannot know the Prime Mover as He exists in Himself, a priori, because of course we do not directly know God. However, as the proof shows, we can apply terms to God by way of His relation to us as cause to effect. Thus, we can apply things in three ways to God from His effects (creation): first, we can deny things in God, second, we can apply certain things to Him by way of preeminence (God is the exemplar of all positive qualities here), and, third, we can apply certain analogies to Him from created things, because created things resemble Him in some way (God is like a rock, God is like a lion, God is like a man, ect.). 


Psalm 50(1):8. For behold thou hast loved truth: the uncertain and hidden things of thy wisdom thou hast made manifest to me.