I understand exactly what Icarus is talking about. I had the exact same idea when I was high, but it made perfect sense and it still applies even after I'm sober. I believe there is absolutely no free will. All your actions and the contents of your mind come from already existing things. What I mean to say is there is a range of things that you can think of, so a human beings actions, in theory, are quite predictable. You can't predict exactly what a person will do because their thoughts are random, but still are restricted to what that person has experienced, and in most situations you can narrow down what a person will do. Shame that only Icarus will truly understand what I'm talking about.
ok ive snapped out of my philosophical state. WEED PWNS!
edit: i remember shortly after i had these ideas, i looked up free will on wikipedia and found some interesting things. ex nihilo nihil fit, for example, which is what icarus was talking about
http://en.wikipedia.org/wiki/Ex_nihilo_nihil_fit