In his new book Free Will (sees Parts I and II of my review here and here), much of Sam Harris’s argument against free will is fueled by assertions — assertions that simply assume what he is trying to prove. In fact, much of his case consists of sheer bluff, as if saying what he is trying to prove with enough bravado is sufficient to prove his case.
“There is,” he says, “simply no intellectually respectable position from which to deny this.” No denying this. Check. “There is no question that (most, if not all) mental events are the product of physical events.” No question. Got it. “My mental life is simply given to me by the cosmos.” Right. Blessed be the Almighty Cosmos.
He argues that we are not aware of the neurological events that produce our thoughts, moods, perceptions, and behavior, and that, since we are not aware of them, they must produce our thoughts. Not only does this not logically follow, it simply assumes that these things are “produced” by neurological events, when this is the very point at issue.
He is singularly impressed by the evidence that neurological events seem to precede the thoughts they “produce”:

The physiologist Benjamin Libet famously used EEG to show that activity in the brain’s motor cortex can be detected some 300 milliseconds before a person feels that he has decided to move … More recently, direct recordings from the cortex showed that the activity of merely 256 neurons was sufficient to predict that 80 percent accuracy a person’s decision to move 700 milliseconds before he became aware of it.

“These findings,” he adds, “are difficult to reconcile with the sense that we are the conscious authors of our actions.” Why? He argues that this shows that “some moments before you are aware of what you will do next, your brain has already determined what you will do.” But before we can decide what we can infer from the evidence, we have to ask exactly what the evidence is.
He appears to be saying that there are two chemical events being detected by scientific instruments: one that is the physical event that causes the decision, and one that is the physical event that constitutes our awareness that we are making the decision.
The first question is how we know which event — the one that Harris identifies as pre-determinative and the one that he identifies as the awareness of making the decision — is the decision itself. He seems to identify the latter event — the awareness of the decision — as the decision itself. But an awareness of a decision isn’t necessarily the decision. In fact, on the face of it, it would make more sense to think that the awareness of making a decision is a separate act from the decision itself. The mental act of thinking about something and the mental act of thinking about your mental act of thinking about something would clearly be two mental acts.
By what reasoning does he say that the first chemical event is pre-determinative and the second what is pre-determined? Why couldn’t the first event be the decision and the second the awareness that we have made the decision? Given Harris’s penchant for making assumptions he has not justified, it seems we are justified in being suspicious. There may be some reason to interpret it the way he does, but he does not give us enough information to know what it is. It is not even clear that he has considered any alternative interpretation than the one that favors his case.
So when Harris asks us what we should think about a situation (which he clearly considers possible) in which experimenters could know, a split second before you made it, what your decision would be, we could simply ask what justifies them in thinking that the neurological event they had thought was the event which caused the decision was not the decision itself, and the latter the neurological event co-incident with awareness of the decision they had just made?
In fact, one question is whether we can ever reliably know the answer to this question at all.
And then Harris makes this rather strange statement:

Consider what it would take to actually have free will. You would need to be aware of all the factors that determine your thoughts and actions, and you would need to have complete control over those factors.

You would? Think of what would be necessary, if what Harris says here is true, to drive a car: You would need to be aware of all the factors that make the car go, and you would have to have complete control over them. I’m pretty sure most people on the road have no clue how their engine was put together or how it works, and they have very little control over how these factors work together at any given moment. But they seem to get around just fine. In fact, Harris’s assertion here is just silly.
Then he makes statements that are simply ludicrous. He says, “If you don’t know what your soul is going to do next, you are not in control.” Huh? You have to know what your decision is before you make it in order for it to be a free will decision? Why? And if this is the case, then what about the neurological event that Harris would say would have to constitute the knowledge of what the decision will be? Would we need to know what that knowledge would be before we had it too? How far back do we need to go?
Then there are those statements the full import of which one must meditate on for long periods of time in highly oxygenated air in order to fully appreciate: “A voluntary action,” he says, “is accompanied by the felt intention to carry it out.” No kidding? Really? “We do not know what we intend to do until the intention arises.” No! Get out!
And all this in preparation for the next chapter, in which we are told that it is those who believe in free will who are not being rational. More later on Harris.