"Man is not fully conditioned and determined but rather determines himself whether he gives in to conditions or stands up to them. In other words, man is ultimately self-determining. Man does not simply exist but always decides what his existence will be, what he will become in the next moment. By the same token, every human being has the freedom to change at any instant. Therefore, we can predict his future only within the large framework of a statistical survey referring to a whole group; the individual personality, however, remains essentially unpredictable"
- Viktor Frankl, Man's search for Meaning
The recent book on Free Will by Sam Harris: http://www.amazon.com/Free-Will-Sam-Harris/dp/1451683405 is relevant here.