Cycel (or anyone),
Since we want to deal with simple physics (post 3252 and others previous to it), let's take a look at a coin toss. It appears random, but of course the outcome is determined by the force of the toss, how long it's in the air, and so on.
So it is with everything we can see in the universe, it's all determined by previous states.
Given this deterministic situation, your brain may appear to be making choices, it may feel like it is, but, like the coin toss above, it's all determined. So, no choice is possible.
That is, no choice is possible if one deals just with the physical world.