The author took part in the first experiments with a split brain (patients whose corpus callosum had been severed, isolating the two hemispheres of the brain). His accounts of those experiments make a fascinating read, as are many other facts about Neurology. Only for these, the book is worth a read. He is on shakier ground when confronted with the age-old question of free will. We actually do not need such accurate information about where and when a specific trait or response happens to be to understand the simple fact that a brain is a physical entity and is, as such, subjected to the laws of physics. The finger that pulls the trigger of a gun and kills someone is activated by a neuronal network. Follow back the path from the neurons that directly contract the muscles all the way to the frontal cortex and you will never find a "free will" neuron that makes the decision. It really does not matter that at its most fundamental level (quantum mechanics), Nature is not deterministic, but random. This randomness is also at work inside the transistor in the device you are probably using to read this, and that does not make your device a free agent. The author's quest to discredit reductionism is simplistic. He keeps on saying that you don't look at a car's mechanical parts to understand traffic patterns. That completely misses the point. That's called 'methodological reductionism' and is not embraced today by anyone. Modern reductionism does not attempt to do that. Rather, it concedes that epiphenomena can and should be studied and understood at its proper level. But that does not mean that emergent properties have causal links which are independent of the fundamental phenomena that explain them. The author's foray into Physics to explain the concept of emergence is misguided. A macroscopic object, like a ball rolling down an inclined plane, is not an example of emergence from quantum mechanics. In fact, quantum mechanics cannot explain why the ball should roll down. This is hardly an example of an epiphenomenon, but simply reflects the well-known fact that quantum mechanics does not explain gravity (you need General Relativity for that). If the author's point was to contribute something new to the question of free will, he has not succeeded. But the journey itself is packed with so many interesting facts and descriptions about the science of the brain that I would still recommend it.
This easy-to-read book is skilfully written for a lay readership by a veteran cognitive neuroscientist, famous for his work on split brain patients. It is based on the author's 2009 Gifford Lectures. It addresses not only the question of free will (Who's in charge? - the title), but also the nature of this "who", i.e. the nature of the self and of consciousness. The book is composed of seven chapters: 1. The Way We Are, 2. The Parallel and Distributing Brain, 3. The Interpreter, 4. Abandoning the Concept of Free Will, 5. The Social Mind, 6. We are the Law, and 7. An Afterword. The American (Amazon.com) website has several elogious reviews of the book that spell out its numerous merits and award it five stars. I agree with many of those positive comments. The book is indeed packed with interesting information about the neuroscience-psychology interface, and is engagingly and clearly written. But it suffers from three weaknesses.
First, in tackling a subject at the intersection of neuroscience and philosophy, the author should have drawn on modern scholarship in both areas. But he fails in this. He describes the work of dozens of modern neuroscientists and psychologists, and briefly mentions a few classical philosophers (Plato, Aristotle, Locke), but has nothing to say about modern philosophical scholarship. There is no mention at all of the contributions of philosophers such as Dennett, Van Inwagen, Kane, Kim, Murphy and Miele, who have all written extensively on the philosophical questions that the book attempts to address (free will, emergence, selfhood, complementarity and downward causation).
Second, Gazzaniga fails to define what he means by "free will". This is a serious defect, because the definitional problem is central to the modern debate about free will. I'm not by any means a Dennett fan, but the subtitle of Dennetts's 1984 book Elbow Room was a true aphorism: "The Varieties of Free Will Worth Wanting". Some varieties don't exist but others do, and those are in Dennett's view (and mine) the ones worth wanting.
Third, in introducing chaos and quantum indeterminism as a defence against hard determinism, Gazzaniga attempts to guide the unsophisticated layman through a deep and difficult controversy, all in eight pages. In my opinion he totally fails to show any relevance of chaos and quantum indeterminism to brain function and free will.
Despite these failings, the book is a fascinating mine of up-to-date information on the cognitive neuroscience related to free will and selfhood. I am glad I bought it.
The mind is an entity that comes to be through the processes of several structures (modules) of the brain. It's unknown what all of these structures are and it is unknown how the result (mind) comes to be. This overall system is referred to as "complex".
"A complex system is composed of many different systems that interact and produce emergent properties that are greater than the sum of their parts and cannot be reduced to the properties of the constituent parts." (p. 71) The mind is such an emergent property. In essence, nobody knows how the hell it happens. Calling it an "emergent property" thing probably sounds better.
You don't get an answer to the question "who's in charge?". Well, to be fair, you seem to get a "sort of no one is" (not a quote). The author quotes Luis Amaral and Julio Ottino as follows: "The common characteristic of all complex systems is that they display organization without any external organizing principle being applied". From this quote it's impossible to tell what "external" is supposed to (not) mean. Mr. Gazzaniga proceeds to discuss the workings of the Google ad auction as an example of no one being in charge. As he says, it is run on algorithms, though. I would propose run -by- algorithms and that the algorithms are in charge. Ultimately in charge would be who or what created and put the algorithms in place. If there's no who - nothing of sufficient personal quality - involved, then there is no free will. We'd all be Google ad auctions. The brain's algorithms aren't (fully) known.
You don't get a good definition of the mind. You do get a vague and superficial account of some elements that allegedly are involved in its genesis. Not knowing how the mind is constituted and how it works then leads to uncertainty in regards to free will. In another vague and superficial account, the author briefly outlines that when no exact predictions can be made (chaos theory; uncertainty principle), determinism (the lack of free will) can't be proven.
You also do get some information on the relevance of unconscious processes. Various modules of the brain work unconscious to the/any person in question, come up with individual results, these results may compete with each other and, after having somehow been evaluated, lead to a final result, an effect. This effect can be you doing something or be you not doing something. So, input (information) is processed by several structures within the brain, somehow integrated and then acted on by the organism/person. At any rate, this only comes to your attention/awareness once it's already been decided. The process of evaluation occurs without you being aware of it until it has been completed. Consciousness is slow; unconsciousness is faster.
"When we set out to explain our actions, they are all post hoc explanations using post hoc observations with no access to nonconscious processing. (...) These explanations are all based on what makes it into our consciousness, but the reality is the actions and the feelings happen before we are consciously aware of them -- and most of the them are the results of nonconscious processes which never make it into the explanations."
This passage (on pages 77 to 78) is less than clear and appears to state that every action is decided and made unconsciously. Later on it is modified into "most of our processing is going on unconsciously and automatically". Some time thereafter (pages 128 to 129), he talks about "[the] buildup of electrical charge that preceded what were considered conscious decisions [which] was called Bereitschaftspotential, or more simply, readiness potential". This goes back to the brain initiating actions unconsciously.
Unfortunately, he doesn't elaborate on it enough. Scope and details remain unclear and missing, among them the possibility of inhibiting readiness potentials and suppressing actions. Furthermore, in this context, he doesn`t discuss the intentional acquisition of automaticity, as in training yourself in order to produce a specific unconscious response in reaction to a specific situation (for example learning to play the piano really well: intuitively). Thus he concludes the respective section with these words: "Conscious volition, the idea that you are willing an action to happen, is an illusion. But is this the right way to think about it? I am beginning to think not." In "thinking not", he proceeds to go back to the uncertainty principle/chaos theory and emergent properties. As mentioned above, that doesn't convince.
This book, as far as I can tell, doesn't add anything new to the matters it addresses (the mind, modularity and free will (see above), also nature vs. nurture and, in its final chapter, the relevance of personal responsibility to criminal law). If you are already familiar with a few popular science books in this field, there's not much sense in going for this one. With all due respect to the author, it lacks in depth, clarity, completeness and novelty of thoughts.
On emergence/emergent properties, I would recommend reading chapter 5 (pages 143 - 181) of Terrence W. Deacon's book Incomplete Nature: How Mind Emerged from Matter (W. W. Norton, 2012) [already available hardcover]. The entire book is relevant.
But, in the book ''Who is in charge'', Michael Gazzaniga has some good insights.
Gazzaniga first introduces us to some of the nuts and bolts of the physical brain. How things are wired and what that might mean. From thereon the book moves on to consciousness, and how consciousness might emerge from the physical brain. Eventually, free will and determinism are discussed.
Obviously, a lot of the issues in this book are only superficially touched upon. And, obviously, it would have been nice with a more thorough discussion about these super interesting issues. But, in a relatively popular book, it is probably not possible to given more details and be more thorough.
The books part of emergence is especially interesting. I.e. how mental states might emerge from the physical parts of the brain, neurons and more. And how these emerging mental states might introduce downward causation that will control and constrain the physical layers. In the book, the details of this is not clear though. I began thinking about software and hardware, and language - but the book doesn't mention that at all. Certainly, it would have been nice if that was explored much more in the book. The section about social control and constraints seems more convincing and intuitively clear. Perhaps, because the mechanisms involved are simpler?
Still, the book is a nice read. And it does give some nice insights on what brains, consciousness and free will might be all about.