If we do not mean to stultify our whole argument, we must begin by proving the existence of God. What do we mean by God? All men use this name to designate that which is higher and more excellent than all other things. Some call this Highest Being the Prime Mover of all things; others call it the First Cause and Principle, or the Highest Good and Supreme Truth. But, whatsoever God may be called, if His name expresses the highest and superexcellent nature, His existence must be acknowledged. This is admitted even by philosophers. It is of His existence that I wish briefly to speak.
Philosophers have proved, most effectually, that everything that moves is moved by something else. Even though men and brutes move themselves, there is in them one thing that moves and another that is moved; for the body cannot move when abandoned by the soul. And, since every movement under the heavens depends on the movement of the heavens, there must be some substance that moves the heavens. Now, does that substance itself move, or does it not? If it does not move, it must be God, who moves all things, but is Himself immovable. But if the substance move, it must then be moved by something else. Now, is that something else immovable, or is it also moved? If it be moved, who moves it? If we continue this chain of argument, we shall see that there must either be one First Mover, or else an infinite series of movements with no First Mover. The second hypothesis is philosophically absurd. For, if there be no First Mover, on which other motors depend, nothing could move, and no order would reign among the highest things. There must, then, be one supreme Mover, whom we call God.
We can deduce a similar argument from the causation of things. Everything in the world is caused. Nothing can make itself. Since then many causes concur to the same effect, and one thing is always prior to another, we must either assume an infinite series of causes, or believe in One Supreme Cause, whom all men acknowledge as God.
Again, amongst natural things we see that one thing is always more true and more perfect than another. This could not be the case, did it not approximate more closely to some Supreme Truth and Perfection. We must, therefore, agree that there exists some Supreme Being. This can be no other but God.
Again, we see how, in the natural order, unintelligent beings proceed by the right means from their beginning to their end. This cannot happen by chance, since they always, or almost always, act in the same manner. There must, then, be some Intelligence that directs them. What can this Intelligence be save God?
To these arguments we may further add, that no natural inclination can be futile. Now all men are naturally inclined to believe in God. From the beginning of the world until now there has never been (as we know from their superstitious rites and sacrifices) any nation so rude and barbarous as not to believe in a God. Since, then, this belief has been common to every era, and to every nation, it must be based on natural instinct. Again, we see how men, when in danger and deprived of human aid, will, instinctively, invoke the assistance of God. This is another proof that belief in His existence is natural to the human soul.