Article 1: Whether the proposition that God exists is self-evident (per se notum)

[Translation from the Latin by Gerald J. Massey]

We proceed thus in this first article. It appears that the proposition that God exists is self-evident:

1. For those things are said to be self-evident to us the knowledge of which is naturally in us, as is clearly the case with first principles. But, as Damascene says at the beginning of his book, knowledge of God's existing is naturally implanted in everybody. Therefore, that God exists is self-evident.

2. Furthermore, those things are said to be self-evident which are cognized as soon as their terms have been grasped, a feature that Aristotle in the 1st Book of the Posterior Analytics attributes to the first principles of demonstration, for as soon as one knows what a whole is and what a part is, he immediately knows that every whole is greater than any of its proper parts. But as soon as what the name God signifies has been understood, the fact that God exists is immediately grasped. For by this name is signified that than which nothing greater can be expressed. But what exists in reality and in the mind is greater than what exists only in the mind. Now, as soon as the name God has been understood, he exists in the mind, so it follows that he also exists in reality. Therefore, that God exists is self-evident.

3. Moreover, that there is truth is self-evident, because whoever denies that there is truth concedes that there is truth, for if there is no truth, then it is true that there is no truth. But if something is true, then it follows that there is truth. But God is truth itself; John 14,6 "I am the way, the truth, and the life." Therefore, that God exists is self-evident.
 

But against this is the following. No one can think the opposite of anything that is self-evident, as Aristotle makes clear about the first principles of demonstration in Metaphysics IV and Posterior Analytics I. But according to Psalm 52 "The fool has said in his heart that there is no God," so the opposite of the proposition that God exists can be thought. Therefore, that God exists is not self-evident.

I reply by saying that that something can be self-evident in two ways; in one way, in itself but not relative to us; in the other way, both in itself and relative to us. For what makes a proposition self-evident is the fact that its predicate is included in the concept of its subject, e.g., man is an animal, for animal is included in the concept man. Therefore, if the concept of the predicate and the concept of the subject are known by all, the particular proposition will be self-evident to everyone, as is clearly the case with the first principles of demonstrations, whose terms are common concepts that no one is ignorant of: e.g., being and non-being, whole and part, and the like. However, if the concepts of the predicate and the subject are not known by us, the particular proposition, considered in itself, will be self-evident, but it will not be self-evident relative to those who are ignorant of its subject and predicate. And it therefore happens, as Boetius says in his book de Hebdomadibus, that certain conceptions of the soul are familiar and self-evident only relative to the wise, e.g., that incorporeal things have no place.

Therefore, I say that the proposition "God exists"is self-evident when considered in itself, because its predicate and subject are identical, for God is his existence (as will be clear later). But because we do not know about God what he is, the aforementioned proposition is not self-evident to us, but it needs to be demonstrated by means of those things that are more known relative to us although less known in themselves, namely, by means of his effects.
 

To the first objection, I reply that some general and confused knowledge that God exists is naturally implanted in us in so far as God is the happiness of man; for man naturally desires happiness, and what is naturally desired by man is naturally known by him. But this is not, strictly speaking, to know that God exists; just as knowing that someone is coming is not the same as knowing that Peter is coming, although Peter happens to be the one coming. For many take the perfect good of man, which is happiness, to be riches; others, pleasures; and others, still some other thing.

To the second objection, I reply that he who hears the name God may perhaps not understand that it signifies something than which a greater cannot be thought, since some have believed that God is a body. But given that someone understands the name God to signify what has just been said, namely, that than which a greater cannot be thought, it nevertheless does not follow that he must understand that which is signified by the name to exist in reality, but only in the apprehension of the intellect. Nor can it be inferred that God exists in reality, unless it is conceded that there exists in reality something than which a greater cannot be thought. But this is not conceded by those who claim that God does not exist.

To the third objection, I reply that the proposition that truth in general exists is self-evident, but that the first truth exists is not self-evident relative to us.
 

St. Thomas Aquinas, Summa Theologiae, Part One, q. 2, a. 2.

Whether it can be Demonstrated that God Exists [Translation by Gerald J. Massey]

We proceed thus to this second article. It seems that it cannot be demonstrated that God exists:

1. For it is an article of Faith that God exists. But the things that belong to Faith are not demonstrable, because demonstration produces knowledge whereas faith pertains to things that are not apparent, as is clear from the Apostle's letter to the Hebrews, 11. Therefore, that God exists is not demonstrable.

2. Furthermore, the middle term of a demonstration is a nature or whatness (quod quid est). But we cannot know of God what he is, but only what he is not, as Damascene says. Therefore, we are not able to demonstrate that God exists.

3. Moreover, if God's existence were to be demonstrated, it could only be done from his effects. But his effects are not proportional to him, for he himself is infinite and his effects are finite, and the finite is not proportional to the infinite. Therefore, since a cause cannot be demonstrated through an effect that is not proportional to it, it appears that God's existence cannot be demonstrated.

But against this is what the Apostle says in his epistle to the Romans, 1, 20: the invisible things of God are detected when the things that have been made are understood. But this would not happen unless God's existence could be demonstrated from the things that have been made, for what must first of all be understood about anything is whether it exists.

I reply by noting that there are two kinds of demonstration. One kind proceeds from the cause and is called demonstration propter quid; and this kind of explanation proceeds from what is absolutely prior. The other kind proceeds from the effect and is called demonstration quia; and this kind of explanation proceeds from those things that are prior relative to us. For, when an effect is more manifest to us than its cause, we proceed from the effect to knowledge of its cause. But from any effect whatsoever the proper cause of its existence can be demonstrated (provided the effect is better known relative to us than the cause), because, since the effect depends on the cause, when the effect has been posited, it is necessary that the cause must preexist. Hence, the proposition that God exists, in so far as it is not self-evident relative to us, can be demonstrated through effects that are known to us.

To the first objection, I reply that the proposition that God exists, along with other things of this kind that can be known about God through natural reason (as is said in Romans 1, 19), are not Articles of Faith but preambles to these Articles, for faith presupposes natural knowledge just as grace presupposes nature and perfection presupposes the perfectible. But nothing prohibits that which is in itself demonstrable and knowable from being accepted on faith by someone who does not grasp its demonstration.

To the second objection, I reply that when a cause is demonstrated from its effect, the effect must be used in lieu of the definition of the cause in order to prove the existence of the cause, and this happens especially in the case of God. Because, to prove that something exists, one must adopt as middle term what its name signifies, and not the nature or whatness of the thing, for the question WHETHER IT EXISTS is prior to the question WHAT IT IS. But the names of God are imposed from his effects, as will be shown later. Thus, in demonstrating God's existence from effects, we can take as the middle term what the name God signifies.

To the third objection, I reply that perfect knowledge of the cause cannot be had through effects that are not proportionate to the cause, but from any effect whatsoever it can be clearly demonstrated to us that its cause exists, as has been said. And so God's existence can be demonstrated from God's effects, although by means of them we cannot perfectly know God in his essence.

St. Thomas Aquinas, Summa Theologiae, Prima Pars (Part One), q. 2, art. 3.

Whether God Exists (Utrum Deus sit) [Translation by Gerald J. Massey]

We proceed thus to this third article. It appears that God does not exist:

1. Because, if one member of a pair of contraries is infinite, it would totally annihilate the other. But that he is something infinitely good is understood by the name God. Therefore, if God were to exist, no evil would be found. But evil is found in the world. So, God does not exist.

2. Furthermore, what can be accomplished through fewer principles does not come about through many. But, the nonexistence of God having been supposed, it seems that all the things that appear in the world can be accomplished through other principles; because those things that are natural can be reduced to the principle which is Nature, and those which are done purposively can be reduced to the principle which is human reason or will. Therefore, there is no necessity to posit the existence of God.

But against this is what is said in Exodus 3, 14, in the person of God: I am who am. (Ego sum qui sum.)

I reply by saying that the proposition God exists can be proved in five ways. The first and most obvious way is that which is taken from the consideration of motion. For it is certain and evident to the senses that some things in this world are moved. But everything that is moved is moved by another. For nothing is moved except as it is in potency to that to which it is moved: however, something moves according as it is in act. For to move is nothing other than for something to be brought from potency to act. Nothing can be brought from potency to act except through some being in act, as the actually hot, namely fire, makes wood, which is potentially hot, to be actually hot, and thereby moves and changes it. But it is impossible that one and the same thing be simultaneously in act and in potency in the same respect, but only in diverse respects; for what is actually hot cannot simultaneously be potentially hot, but is rather simultaneously potentially cold. Therefore, it is impossible that something be mover and moved in the same respect and at the same time, i.e., that it move itself. Therefore, it is necessary that everything that is moved be moved by another. So, if that by which it is moved is itself also moved, it is necessary that it be moved by another, and that one by still another. But we may not proceed thus to infinity, because there would then be no primary mover, and consequently no other movers, because intermediate movers move only through the fact that they are moved by a primary mover, as the stick moves only because it is moved by the hand. Thus, we necessarily arrive at some primary mover, which is moved by nothing; and everyone understands this primary mover to be God.

The second way comes from the concept of efficient cause. For we find that there is an order to efficient causes in sensible things, but we do not find -- nor is it possible -- that something is the efficient cause of itself, for it would then be prior to itself, which is impossible. But it is not possible to proceed to infinity in efficient causes, because in every ordered series of efficient causes, the first is the cause of the intermediate, and the intermediate is the cause of the last, no matter whether there are many intermediate causes or only one intermediate cause; for the cause having been removed, the effect is automatically removed. Therefore, if there were no first in a series of efficient causes, there would be neither a last nor any intermediate causes. But if we proceed to infinity in efficient causes, there will be no first efficient cause, and thus there will be no intermediate efficient causes nor any last effect, which is plainly false. Therefore, it is necessary to posit some first efficient cause, which everyone calls God.

The third way is taken from the possible and necessary and goes thus. We find some things that are possible to be and possible not to be, since they are found to be generated and corrupted, and consequently possible to be and possible not to be. But it is impossible that all such things always exist, because what is possible not to be, at some time does not exist (quia quod possible est non esse, quandoque non est). Therefore, if all things are the type that is possible not to be, at some time there was nothing in reality (Si igitur omnia sunt possibilia non esse, aliquando nihil fuit in rebus). But if this is true, there would also be nothing now, because what does not exist does not begin to exist except through something that exists. Therefore, if there was no being, it was impossible for something to begin to exist, and so now there would be nothing, which is obviously false. Therefore, not all beings are of the aforementioned possible type (possible not to be), but it is requisite that there be in reality something necessary. But every necessary thing either has a cause of its necessity outside itself, or not. But we may not proceed to infinity in necessary things that have a cause of their necessity, just as we could not proceed to infinity in efficient causes, as was proved already. Therefore, we must posit something which is necessary per se, not having a cause of its necessity outside itself, but which is the cause of the necessity of other things. All refer to this necessary being as God.

The fourth way is taken from the gradations that are found in things. For we find some things that are more good and some less good, some more true and some less true, some more noble and some less noble, and so on. But more and less are predicated of diverse things according as they approach or recede from something which is maximal, as the more hot is that which approaches the maximally hot. There is, therefore, something which is most true, and best, and most noble, and consequently, maximally being, for the things that are maximally true are maximally beings, as is said in the 2nd Book of Aristotle's Metaphysics. But what is said to be maximally so-and-so in any genus is the cause of all the things that are in that genus, as fire, which is maximally hot, is the cause of all hot things, as is said in the same book. Therefore, there is something which is to all beings the cause of their being and of their goodness and of every one of their perfections, and this we call God.

The fifth way is taken from the governance of things. For we see that some things that lack cognition, namely natural bodies, operate for the sake of an end. This is apparent from the fact that they always or frequently operate in the same way so that they obtain that which is best, whence it is clear that they do not attain their end by chance but by intention. But things which do not have cognition do not tend toward an end unless directed by some cognitive and intelligent being, as the arrow by the archer. Therefore there is some intelligent being by which all natural things are ordered to their end, and we call this thing God.

To the first objection, I reply that as Augustine says in his Enchiridio, God, since he is maximally good, would in no way permit there to be anything evil in his works unless he were so omnipotent and good that he could even bring good out of evil. Therefore, it pertains to the infinity of God that he permits evil things to exist that he might elicit good things from them.

To the second objection, I reply that, since nature operates for the sake of a determinate end through the direction of a superior agent, those things which are accomplished by nature must also be reduced to God as their first cause. Similarly, also, the things that are done purposively must be reduced to some higher cause than human reason and will, because these latter are mutable and fallible; but it is requisite that all mobile things and all things that can fail be reduced to some first immobile principle which is necessary per se, as has been shown.