The first question is whether a layperson can enjoy this book about such a profoundly complex subject as the human brain and its relationship to sentient consciousness. The answer is YES! Not because the hyper-complex nature of the subject is "dumbed down" but because Michael Gazzaniga is a gifted writer talented in expressing the most complex ideas in easy-to-understand sentences. He has a most delightful sense of humor that conveys his insights in a light-hearted and enjoyable manner.
Let me also say up front that this book is useful in explaining how the brain operates on two levels. Gazzaniga explains how the "right brain" is driven by the senses and acts on an immediate, subconscious level. The "left brain" applies a conscious after-the-fact reasoning that attempts to make sense of the actions that the subconscious mind has already taken. The left-brain's "interpreter module" is always at work inventing theories to "explain" what the right half of the brain has already "decided" on the basis of reflexive subconscious instinct.
Gazzaniga gives powerful examples of how easily the "interpreter module" can be deceived into coming to false conclusions. Suffice it to say that our brains can work against us by making poor decisions on the basis of perceived information that is false or unreliable. Understanding how the conscious mind rationalizes decisions that the subconscious mind has already acted on has relevance in helping us to make better decisions in every aspect of life. The book should be read for this reason alone. It explains how our conscious mind is far more fallible than we ever imagined.
The book answers some most intriguing questions about the relationship between the brain and consciousness:
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We are still left with this thorny little problem: What is going on in the brain to produce this magnificent ability that humans have, how did it come about, and how do you capture it? Fortunately for job security and today's graduate students, the mystery is alive and well, but some of the secrets are being revealed, which we will now explore.
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Here are some of the mysteries revealed:
* Are the brain's neural circuits hard-wired by DNA genetics, or are they created by the acquisition of experience as the organism lives?
* Does the brain "learn" by experience or is it pre-programmed with instinctive responses that are activated by encounters with reality?
* Are babies born with brains already "wired" to understand physical properties, for example why dropped objects fall down but not up, or why animate objects differ from inanimate ones?
* How did our brain evolve from the brains of lower primates? Which of our evolutionary human ancestors would be recognized as the first "human?"
* Are there unique structures in the human brain that make it qualitatively superior to every other species?
* Are the neurons in the human brain structured differently from those in the brains of other animals?
* Are particular mental processes and memories stored in one location in the brain or are they dispersed throughout the brain as a whole?
* Is the brain a "bottom-up" or "top-down" device, i.e. does consciousness control the brain, or is consciousness the sum of the brain's "dumb / automatic" processes?
Gazzaniga answers these questions in interesting detail, in so far as they CAN be answered based on our current state of knowledge. Some of the answers are surprising. For example, it seems that certain survival behaviors (fear of snakes and other predators, for example) ARE hardwired in the brains of humans and animals, but that over a period of thousands of years these instincts have been shown to "wash out" in cases where predator species have become extinct and are no longer threats. Gazzaniga explains numerous ingenious experiments that discern which behaviors are learned and which are innate. There are many surprising revelations about the structure and function of the human brain.
Gazzaniga also wonderfully explains that consciousness is a complex phenomenon. He says trying to understand consciousness by analyzing neurons in the brain would be like trying to figure out the traffic patterns of a large city by looking at the carburetor of one automobile!
Thus has Gazzaniga explained the FINITE capacities of the human brain up to the current state of knowledge. What is lacking is a theory to explain why the brain has a seemingly INFINITE capacity. Every structure in the universe appears to have constraints except the human brain. As we live our lives we accumulate a mental image of every sight, sound, and physical activity we have experienced since assuming consciousness. We layer more memories into our consciousness without losing the old. Our ability to learn seems to be unlimited. A person who is fluent in five languages can become fluent in five more.
HOW can an organ the size of a bowling ball store what appears to be an infinite amount of information? Can this be a purely biological, chemical, and electrical process? Is there some hidden dimension to the brain that CAN'T be explained in terms of physical processes?
And WHY HAVE our brains acquired the power to discern the nature of the universe? We are able to express in mathematical formulas the entire spectrum of the universe, from the quantum mechanics of the subatomic scale to the megastructures that anchor the galaxies. A few pounds of matter in the head of each of us is able to comprehend the entire scale of creation!
Our brain is unique as the only anti-entropic entity in the universe. The natural trend of the universe is that order descends into chaos. The brain creates order FROM chaos. The brain has the capacity to create fantastic wealth from the most common materials that are found in nature. It allows us to create the most sublime artistic expressions.
The brain's capabilities seem to go far beyond the requirements of mere evolution to insure the survival of the species. Wouldn't human beings be more prolific as a species if we were a bit LESS intelligent, smart enough to feed and breed but NOT smart enough to divert energies into non-reproductive agendas like art and philosophy? (Gazzaniga might express the question as: "Why did the conscious aspect of the brain develop when the subconscious works so well?" Consciousness slows us down with rationalizing decisions that the unconscious mind has already made, wasting time and energy and coming to conclusions that are often wrong.)
I know there is no scientific basis for answering these questions yet, but it sure would have been interesting if Gazzaniga had given us his speculative insights!* Also the book is a little weak in the back chapters because it goes into a relatively uninteresting discussion of how consciousness relates to ethics, such as why some humans are altruists and some are criminals. This question boils down to "free will" --- whether or not we really have any conscious choice about the decisions we make.
Discussions along these lines have always seemed pointless to me. If we don't have free will then we are merely robots responding to stimuli. If that were so there would be no need for conscious decision making, which Dr. Gazzaniga points out time and again is an inefficient and sometimes even detrimental aspect of our brains. The fact that we ARE sentient proves to me that we have free will. Otherwise, why waste the body's resources creating a conscience? Isn't it a law of nature that energy is never expended for no purpose? I am tired of this discussion and would have rather read speculations as to how the brain can store a seemingly infinite amount of information and process that information so as to discern the nature of the universe.
The discussion of free will aside, this book is a fascinating, practical, and entertaining read for laypersons. It thoroughly discusses the finite aspects of the brain, but would have been even more interesting if Gazzaniga had engaged in a bit of speculation about the brain's seemingly infinite capabilities. The insights into the mechanisms of the brain and its relationship to the consciousness we call the mind are more valuable than what I've read in every previous book on the subject combined.
* if Gazzaniga had given us his speculative insights!
Connectome: How the Brain's Wiring Makes Us Who We Are by Sebastian Seung was released on 2/7/2012. It is an excellent complement to this book. It contains exactly the types of speculative insights I was looking for, such as whether we will ever learn enough about the functioning of the brain's neural networks to duplicate human intelligence in a machine, or to immortalize ourselves by uploading our consciousness.