This is a really tired old argument that theists keep bringing up and no matter how many different ways I try to explain it, they still don’t seem to get it. I thought literally drawing a little picture might help, so here’s my super advanced MS Paint art.
The problem goes like this: Some theists like to claim that their god is all knowing AND that they have complete free will when it comes to making choices in their lives. This logically cannot be true, and he’s why:
Here is a track. Starting from left to right there are two choices at every intersection with four final outcomes. (Life in infinitely more complex than this, but this track is sufficient to illustrate my point.)
God, being all knowing, would know that was the path you were going to take. If he had a chart up in heaven keeping track, it would match the path you would eventually end up taking. (He knows everything, including the future, he knows if you’re going to go left or right and where)
Now say you want to be tricky, you’re feeling random, sporadic. You come to the 2nd of 3 intersections and while your decide to go left, you suddenly switch to go right (the green line) at the very last second! You had complete free will to make that split second change, right? Wrong.
Remember, God knows EVERYTHING. He knew you were going to try and be tricky, changing at the very last moment. Because of this, God’s chart would not look like the earlier version. Instead it would look like the one below.
If God is all knowing, than your future is already planned out for you; you do not have free will. You can never NOT do what the all knowing God knows you are going to do.
The ability to choose is an illusion. By the simple act of his knowing, your actions are predetermined. This includes whether or not you are going to sin and go to hell. In short, God has planned for billions of people to sin and go to hell before they were ever born.