Argument against God's existence from the impossibility of omniscience and free will:

by Matt Slick

Argument from the impossibility of omniscience and freewill:

1. God is omniscient
2. God has a free will
3. Entities with free will have non-determinate futures
4. Omniscience entails foreknowledge
5. If an entity knows the future, the future is not non-determinate
6. From 3,5: Therefore there are no omniscient epistemic agents who have free will
7. Therefore god is not omniscient and/or god does not have free will
8. Therefore god does not exist

Refutation

1. God is omniscient
2. God has a free will
   1. Free will must be defined before the argument can be attempted.  Does it mean to be able to choose anything, even something contrary to one's nature; or, does it mean being able to choose something consistent with one's nature?
   2. God is free to do whatever he desires. God is not free to act in a manner contrary to his nature.  No Christian theologian teaches he does.
3. Entities with free will have non-determinate futures
   1. This is an assumption that has not been proven. A person can freely choose to act and have that act be known by God, but God knowing what a person freely chooses to do does not mean the person wasn’t free to choose it.
   2. The determination of a future event chosen by a free will restricts the future event to that choice because the person had freely made that choice.  The person was free to choose it or something else, and the choice is determined at that time.
4. Omniscience entails foreknowledge
   1. What is foreknowledge? Knowing what will happen in the future by extrapolation, or knowing by experience since God’s existence is everywhere, all the time? Foreknowledge then wouldn’t be a looking into the future, but a knowing of the future free will choices of people.
5. If an entity knows the future, the future is not non-determinate.
   1. Knowing what a person chooses to do does not mean the person has not freely chosen it. Whatever the person freely chooses to do is what is known. If the person would have chosen something different, that is what would have been known. So, the argument is invalid.
6. From 3,5: Therefore there are no omniscient epistemic agents who have free will
7. Therefore god is not omniscient and/or god does not have free will
8. Therefore god does not exist