A person’s free will is what drives most of their actions and determines their consequences in the course of one’s life. It encompassses almost everything that a person values in life. The framing of laws, politics, religious ethics, and intimate relationships would not be possible without the ability of people to think freely. Free will also puts into perspective the idea that feelings of regret or personal achievement are a result of a person’s own thoughts and actions.
Benjamin Libet, a physiologist, once demonstrated that brain activity in the motor regions begins about 300 milliseconds prior to a person’s actual thought. In another lab, MRI data has gone on to show that what a person considers a “conscious” decision has in fact taken place in the brain around 10 seconds earlier than they become aware of it. Such findings make the author question the existence of free will.

According to the author, the concept of free will has gone beyond the confines of philosophical seminars and will go on to question the religious notion of a "sin" and the persistence for punitive justice. The Supreme Court considers free will to be a "universal and persistent" foundation of the judicial system. Considering this, the author throws open the debate that any scientific developments that contradict the so called belief of free will would question the practice of punishing people for their crimes. In Free Will, Harris puts forth various ideas and views while looking at them from a scientific perspective and actually questions the very existence of a human being’s free will.