Hello Heidi:
I certainly have no disagreement with the claim that Bob does not know that his choices are limited. But how does this work against the substance of my argument? Whether or not Bob knows this, the fact that God knows his future takes away Bob's free will. Why? Imagine Bob where he is at this very moment. Let's say he is in his car on the way to his job in Hackensack, New Jersey. If God knows that he will go to the Hackensack McDonalds for dinner, his freedom to choose is indeed limited. He does not have the freedom to get in his car, drive to the airport and fly to LA for dinner.
To me this is pretty clear. The common sense notion of free will is that we each have some degree of freedom to choose - some aspect of our future that we get to control. Of course, no one would say we have complete freedom. We cannot do things that are beyond our capabilities - I cannot run a 4 minute mile even if I want to. But what does free will mean if we do not even have a smidgen of control over our future?
If God knows everything about my future - what my next thought will be, where I will eat lunch, when I will make a mistake and run a red light, etc. how can I say, from the perspective of being me at the instant that I write this post, that I have freedom of choice? Logical consistency demands that my life path follow the path that God knows I will follow.
So I may have the illusion of free will, but I have no free will in point of fact. Perhaps when you say that we have free will, you really mean we have the belief that we have free will. If so, I am with you.
However, I do not see how you can justify your claim that we are responsible for our actions. How can we be responsible if our free will is not real? Foreknowledge is predestination, as these terms are commonly understood.
Again I ask, what exactly is wrong with my argument? You have pointed out correctly that Bob does not know his choices are limited. But surely, this is beside the point. I may not know that my workmates have placed a "kick me" sign on my back, but that ignorance does not change the facts of the matter.