In this argument proposed by an atheist, he attempts to demonstrate that God cannot exist because he says there is an incompatibility between God’s perfect knowledge of the future and His free will. But the argument fails because it does not include the fact that when a person chooses an action, the person is restricting his other choices. He freely chooses what he desires. So, my knowledge of knowing what I choose to do exactly 5 seconds from now (i.e. drink a glass of water), does not mean that my knowledge of it necessitates my lack of ability to choose otherwise when the time comes. I simply know what I’ve chosen to do. Why? Because it’s what I freely chose to do at that time.  Knowing in advance doesn’t mean I can’t do something different as though something is restricting me.

An argument against God’s existence from the impossibility of perfect knowledge of the future and free will

1. God has perfect knowledge of everything that he is going to do in the future.
2. God cannot be wrong about his knowledge.
3. God infallibly knows he will perform a certain action at a particular time.
4. When that particular time arrives, God cannot choose to act differently.
5. Therefore, God does not have free will.
6. Therefore, the God of the Bible does not exist.

Refutation

1. God has perfect knowledge of everything that he is going to do in the future.
2. God cannot be wrong about his knowledge of the future.
3. God infallibly knows he will perform a certain action at a particular time in the future.
4. When that particular time arrives, God cannot choose to act differently.
   1. If God knows that he will perform a particular action, it is because he has freely chosen to perform that action based on his perfect knowledge. This necessarily means he has free will, which violates premise 5.
   2. When it is time to perform what has freely chosen to do, he will necessarily do it because that is what he has freely decided to do based on his perfect knowledge–which means he will not choose to do something different.
   3. If he had wanted to choose to do something different later on, he would have decided to do that in the first place; otherwise, he would not have perfect knowledge.
   4. So, the argument fails because it states that God has perfect knowledge (decides to do something) and also denies that God has perfect knowledge (decides to do something different later). Therefore, the argument is self-refuting.
5. Therefore, God does not have free will.
6. Therefore, the God of the Bible does not exist.