Arguments for the Existence of God¶
Note
This section is still a work in progress
I’ve come across many arguments for and against the existence of God. I thought it useful to compile them here along with their different versions by different thinkers both ancient and contemporary. All of the arguments here rely only on human reason without divine revelation. This type of information would fall under the category of natural theology.
Notice that not all of these arguments are written in a strict form where the premises and conclusions are identified as such. It is up to you when reading them to extract the inherent logical form.
The Argument from Motion¶
This starting point for this argument is the observation that things in the world are constantly changing (in motion).
From The Summa Theologiae Prima Pars Q2, A3
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.
Note
Dependencies
Act and Potency, A co-principle obtained by understanding that being can be subdivided into actuality and potentiality. See metaphysics.
The Argument from Contingency¶
This starting point for this argument is the reflection on the non-necessary nature of being.
From The Summa Theologiae Prima Pars Q2, A3
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.
From Answering Atheism
P1. Everything that exists has an explanation for its existence in itself or in something outside of itself.
P2. The universe does not have an explanation for its existence in itself.
C1. Therefore, the universe has an explanation for its existence outside of itself.
In the above argument, premise one and two support the conclusion, that the universe has an explanation outside of itself. That conclusion is then joined to another premise and yields the final conclusion:
P3. Any explanation outside of the universe is God.
C2. Therefore, God exists.
Note
Dependencies
The Principle of Sufficient Reason (PSR), A principle obtained by reflecting on the abstract nature of being coming into existence. See metaphysics.
The Problem of Evil¶
I would be remiss if I didn’t include what some say is the strongest positive argument against the existence of God.
From The Summa Theologiae Prima Pars Q2, A3
Argument:
It seems that God does not exist; because if one of two contraries be infinite, the other would be altogether destroyed. But the word “God” means that He is infinite goodness. If, therefore, God existed, there would be no evil discoverable; but there is evil in the world. Therefore God does not exist.
Response:
As Augustine says (Enchiridion xi): “Since God is the highest good, He would not allow any evil to exist in His works, unless His omnipotence and goodness were such as to bring good even out of evil.” This is part of the infinite goodness of God, that He should allow evil to exist, and out of it produce good.