One of God’s defining properties is omniscience, i.e. for every true proposition, he knows that it is true. It follows that God can know in advance what your actions will be. But, if that is true, then are any of our actions really free?
(1) God knows on Monday that I will go to a party on Tuesday (premise)
(2) Necessarily, if God knows on Monday that I will go to a party on Tuesday,
then I will go to a party on Tuesday (premise)
(3) So, necessarily, I will go to a party on Tuesday (from 1 and 2)
(4) So, if I go to a party on Tuesday, I do not go freely (from 3)
If God knows in advance what I’m going to do, and he cannot be wrong, then, when Tuesday comes, I will have to go to the party. If I do not go, then God would have been wrong, and that is impossible, because an omniscient being cannot make such a mistake. But, if I have to go to the party, then I do not go freely.
So, if God knows in advance what your actions will be, then none of your actions is free. Conversely, if some of your actions really are free, then God cannot know in advance what they will be, and hence he cannot be omniscient.
Some theists have concluded that God does know our future actions, and hence that we are not really free, i.e. our actions are predetermined by his foreknowledge. Others have said that since we are free, our actions are not knowable in advance. But there is a solution: the argument commits a logical fallacy:
In general, one cannot infer ‘necessarily q’ (3) from the two premises ‘necessarily if p, then q’ (2) and ‘p’ (1). The necessity of the conditional (i.e. ‘if p, then q’), does not imply the necessity of the consequent (‘then q’; I will go to a party on Tuesday), even when the antecedent is true (‘if p’; God knows on Monday that I will go to a party on Tuesday). All that follows from premises 1 and 2 is that I will go to a party on Tuesday.
If God foreknows that I will do X, then if follows that I do not do not-X. What does not follow is that I cannot do not-X. God’s foreknowledge does not exert a coercive causal power that gets a grip on me and forces me to go to the party on Tuesday. His foreknowledge exerts no influence on my behavior, and thus do not threaten my freedom. I do not go to the party in virtue of God’s foreknowledge; rather, God foreknows in virtue of the fact that I go to the party.
There is no real problem here. Theists have been unnecessarily concerned about God’s foreknowledge and human’s free actions: the two concepts are not in any conflict.
Everitt, N. (2004). The Non-Existence of God. New York: Routledge.