There is no question that our attribution of agency can be gravely in error. It is my contention that it always is. (p. 25)
"Free will" is a very short book that you could skim through in about the same time it takes to watch this talk from Harris on the subject of free will. It is also very clearly written. Harris argues that free will, at least as most people understand it, simply does not exist; we are not free agents who are in control of our thoughts or actions.
According to his taped confession, Komisarjevsky stood over the sleeping man for some minutes, hesitating, before striking him in the head with a baseball bat. He claimed that the victim's screams then triggered something within him, and he bludgeoned Petit with all his strength until he fell silent. (p. 2)
The opening paragraph is followed by an account of a brutal multiple murder (which took place over a number of hours). Harris segues shortly thereafter into discussion of free will and daily choices of what to eat and drink. The juxtaposition (albeit indirect) may seem tasteless. More pressing is that it really does miss a distinction between decisions to which we do not devote much thought and decisions to which we do. Harris does highlight how some actions may involve a greater degree of conscious deliberation. However, he also points out that those factors that enter into conscious deliberation do so via unconscious mechanisms. Nonetheless, I feel he goes too far in suggesting we do not have free will simply because we cannot control thoughts that come into our conscious awareness-if we have a conscious "veto" over our decisions, as some models of reasoning suggest, then even though we may not control where our thoughts initially come from, we may at least exercise some control over our behaviour.
Harris takes in some fascinating neuroscience research in this area. He highlights a famous experiment demonstrating that in motor regions of the brain (which are associated with the initiation of behaviour) neural activity occurs prior to conscious awareness of the intention to act. However, this phenomenon occurs over the course of a few seconds or less, and is likely of limited influence when it comes to deliberating over a choice carefully, where options A and B might be evaluated repeatedly on several attributes before any overt behaviour is produced by the person making the decision.
Harris outlines a deterministic view of human thought and action, which he feels is incompatible with the idea of free will. Daniel Dennett (who Harris indicates is both a friend as well as an opponent on this particular issue) has defended the idea that determinism may be compatible with at least a modest version of free will. We may accept a deterministic stance whereby someone could only have done x, and not y, given all the factors in their life up to that point, PLUS all the details of their environment. Nonetheless, Dennett argues, if we take the environment (which exists outside of the person's self, and for which they are generally not really responsible for), if the person may have acted differently had some small aspect of the environment been different, then it probably is fair to say that the person has some degree of free will.
The book concludes with thoughts on the moral/ethical implications of free will being simply an illusion. Dennett has weighed in on this issue as well, suggesting that the idea that free will doesn't really exist appears to make people act in a less ethical fashion (because, after all, "how could they do otherwise"?), and indeed both Dennett and Harris cite interesting research suggesting that encouraging a view that free will does exist encourages research participants to behave in a more ethical fashion than if they are encouraged not to believe in free will. Harris does not offer any easy answers to this issue, although he does posit that moral responsibility "overall complexion of one's mind" rather than "the metaphysics of cause and effect". (At this point, I feel he might be alluding implicitly to the point I made above about weighing up options consciously, although he seems to stop short of saying as much).
On the subject of ethics, Harris further suggests that the legal system (e.g. in how it deals with violent offenders) could shift from less of a focus on punishment to a greater focus on safety and rehabilitation. (Such a shift in focus could sometimes lead to longer prison sentences for violent offenders, if they have served a sentence that is considered fair in terms of punishment, but the criminal nonetheless maintains a high risk of committing a similar crime outside of prison).
In conclusion, if you have always had a simple faith that you have more-or-less complete free will, this book will certainly make you think twice about whether this is the case. Although I feel it is not a complete refutation of free will, it is likely to make most readers revise their view of what free will really is. leaving them with a more modest estimate over the extent to which they (and others) are in control.
Book review: "Intuition Pumps" by Daniel Dennett