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.
CHAPTER VII.
GOD IS NOT A BODY, NOR THE FORM OF A BODY, NOR IS HE A COMPLEX SUBSTANCE.
No true philosopher entertains the slightest doubt that God is not a body, nor the form of a body, nor a complex substance. It would be impossible that God should be a body, seeing that He is the immovable Mover of all things; for one body, unless it first move itself, cannot set another in motion. Again, as spirit is more noble than body, God, were He a body, would not be the noblest of all beings, neither would He be the Supreme Ruler, since the body is governed by the spirit.
We must further hold, that God is not the form of a body, as the soul is the form of the human body; because that which exists of itself is far more noble than that which exists in others. Consequently, as God is the most noble of all things, He must exist in Himself, and not in any body. Again, things composed of matter and of form are more perfect than matter alone and form alone; for the simple reason that the whole is always more perfect than its parts. If, then, God were the form of a body, there would be something more perfect than He; for the combination of matter and form would be more perfect than form alone. It would further follow that God could not act by Himself; since, as form has no being without matter, it cannot operate without matter. Hence, as God would need others for His operations, He would not be the First Cause.
It is, likewise, evident that God is not a complex Being, but Pure Act and Simple Substance; for every complex being depends on others, and composite bodies depend on those that are simple. Since, therefore, God is the First Cause, independent of all others, and the one on whom all things depend, He cannot be a complex Being, but must be Simple Act. Again, were He a complex Substance, He could not be the First Supreme Being in the universe; for complex bodies do not precede their parts, but result from them; and the union of these parts could not take place, had not some first cause preceded them. We must conclude, therefore, that God is Simple Substance and Pure Act.[18]