In this series so far, I have shown that there is an eternal, necessary, unchangeable first cause of one particular change of one thing in the world. But before I can go further, I will show that God is simple. In an earlier post I mentioned that there is a difference between essence and existence. Essence is what a thing is and existence is that it exists. In God, there is no difference between these two things. God’s essence is the same thing as his existence.
This can sound really confusing. Let’s begin by reminding ourselves of the distinction between essence and existence as it might apply to God. In this series I am proving that God exists. In order to have this discussion at all, we generally agree that there are certain characteristics, or traits that God has. This is his essence. For example, if I claimed that there is one being that created all things on earth, is all knowing, perfectly good and all powerful everyone would recognize that this is God. But when an atheist says that there is no God, she is claiming that there is no being that fits that description. Or in other words, no being exists that has that essence.
So why should we think that God’s existence is the same thing as his essence? We should think so because God is an unchangeable first cause. The first cause, as I have already proven, is necessary. Remember my reasoning for this. God exists because of nothing else. If he existed because of something else, then he would not be the first cause of that particular change. So it is a part of his very essence to exist. So this means that part of his essence is his existence. So either all of his essence is existence or only part of it is. Assume that part of it is. Then we can ask what is the reason why that part of his essence exists. It is either himself or something else. If it is something else, then he is not the first cause. If it is himself, then that part of his essence is either changeable or unchangeable. If it is changeable, then we have a contradiction, because we have already proven that God is unchangeable. If it is unchangeable, then we must examine the relationship between the essence and the existence of God.
In most things, they exist because of essence is made to exist by something else. We cannot suppose that God makes his own essence exist. If that were true, then God would have to exist in order to make himself exist. But then he would have to exist before he exists. This before is not temporal (remember that this argument is vertical). This before is causally prior. Therefore, God cannot make himself exist. But if part of the essence of God is not his existence, and God causes this unchangeable part of himself to exist, then God causes himself to exist. Therefore, God’s existence and God essence are the same thing.
There is a difference between understanding that God’s essence is his existence and understanding what this means for God. Although I cannot go into the issue here, one is possible and the other is not possible.