Hi, Justin. Asgara already supplied a sufficient response to your post, but I thought I'd phrase one for you in my own words in order to give you a few perspectives...
JustinCy writes:
How does foreknowledge contradict free will? In other words, how does someone knowing what I am going to do negate the fact that I had free will to do otherwise?
The important qualification that is often overlooked is the supposed infallibility of God's foreknowledge. Since it is supposed to be impossible in principle for God to have erroneous knowledge, all of the future events which he knows thus must be precisely
determined in order to be known. It is a contradiction to say that God infallibly knows the exact future state of any propogating system, and that future state is still undetermined. In other words, if the state were truly undetermined, then God could not know infallibly and precisely what it is. Knowing that future state precisely and infallibly requires determining exactly what it is to be known.
I know exactly what I am going to do in the relative future of the event I am watching, but does that mean that I didn't have free will to do otherwise?
Well, strictly speaking, the uncertainty principle prohibits this from being true because it is impossible in principle to know completely and precisely any single state of the universe. You may be able to predict the future state of your body with a high degree of accuracy, but you cannot predict it with infallible accuracy.
Is there a logical contradiction between foreknowledge and free will?
Yes. That is, between
infallible foreknowledge and free will.
1.) I have free will with respect to action A at time T if and only if there exist possible worlds A
1, A
2, A
3, ... A
n in the future (at time (T + 1)) of action A.
2.) Divine (infallible) foreknowledge requires that all worlds contrary to that which is divinely known are impossible (because those worlds represent the possibility for God to be wrong, which, according to the definition of infallibility, is impossible, hence those worlds do not exist).
3.) Suppose that at time (T - 1), God infallibly knows that world A
G exists at (T + 1).
4.) According to (2), all other worlds besides A
G are impossible, and therefore do not exist.
5.) Therefore I do not have free will with respect to action A.
Out of curiousity, have you read any interesting pieces on this subject?
Lots of odds and ends that I've found on the net. Nothing comes to mind that's worth singling out.
I do agree, though, that the free will defense as a solution to the problem of evil has contradictory (or atleast unconventional) implications about the Nature of Heaven.
I agree. If evil necessarily follows from free will, then free will can't exist in Heaven where there is supposed to be no evil.
...but that's a different thread altogether...