BOOK REVIEWS : A Powerful Glimpse Into the Brain

The Cerebral Symphony: Seashore Reflections on the Structure of Consciousness by William H. Calvin (Bantam Books: $19.95; 401 pages)

One of the ongoing delights of this book-reviewing gig is that I get to meet such interesting people: the scientist-authors of books on topics from anthropology to zoology. (I don’t actually meet them, of course, but I read their books, which in some ways is even better.)

And of all the authors, the most interesting as a group are those who write about the brain, tackling the modern version of the mind-body problem: How does consciousness emerge from flesh and blood? Who and where is the I that seems to exist inside each of our heads, the unifier of our experiences, the orchestrator of our thoughts, the narrator we recognize each morning when we wake up?

How do I decide what I will do next?

No one really knows the answers to these questions. They are as shrouded in mystery as any questions in science. But William H. Calvin, a neurobiologist with a gift for making things clear, has thought about them a lot and has a hypothesis to propose. In “The Cerebral Symphony,” he shares with us a great deal about the brain, the mind and himself.

Calvin does this against the background of Woods Hole, the site of the Marine Biological Laboratory on Cape Cod, where he walks and wanders. The nature he observes around him sparks his thoughts about the nature within him. This is a technique that Calvin has used before in “The River That Flows Uphill,” where a trip down the Colorado River through the Grand Canyon provided the setting for his thoughts about biology and physics.

Now his setting moves east, where his descriptions of the abundant wildlife and other natural history of one of this country’s most beautiful spots are almost a match for his descriptions of the inner workings of the brain.

He looks at the animals around him and wonders how they decide what to do next. Some if not most of their behavior is instinctive, but nonetheless they make choices.

“Purpose seems so different from chance,” Calvin writes, “but Darwinism suggests that you might be able to have your cake and eat it too: Chance plus selection, repeated for many rounds, can achieve much. Can Darwinism achieve purposeful behavior, especially our planning-for-the-future behavior that has been such a powerful drive toward both civilization and ethics? Is it, indeed, the foundation of consciousness?”

Calvin’s answer is that it can and does. The same process of natural selection that has worked over billions of years to drive the development of living creatures from amoebas to us is also at work inside our brains--but very much faster. He says our brains are “Darwin Machines.”

The billions of neurons inside our brains are busily doing their thing--producing thoughts. We’re not aware of it. The better ones bubble to consciousness. We evaluate their utility. The thoughts that work survive; those that don’t work don’t.

Calvin writes:

“My minimalist model for mind suggests that consciousness is primarily a Darwin Machine, using utility estimates to evaluate projected sequences of words/schemas/movements that are formed up off-line in a massively serial neural device.

“The best candidate becomes what ‘one is conscious of’ and sometimes acts upon. What’s going on in mind isn’t really a symphony but is more like a whole rehearsal hall of various melodies being practiced and composed; it is our ability to focus attention upon one well-shaped scenario that allows us to hear a cerebral symphony amid all the fantasy.”

Whether this hypothesis works or not I leave to readers and other neurobiologists to decide. I haven’t a clue whether the brain actually works this way or whether it is even a good metaphor for how the brain works. It does have the advantage of extending a very powerful idea in biology--Darwinian evolution--into another realm. In general, that’s a plus.

More important than Calvin’s conclusion is how he gets there. His book is a fascinating romp through current knowledge about thought and thinking. Calvin is a rare scientist who can concentrate on the big picture and on the small picture at the same time. It’s almost as if he can use a telescope and a microscope simultaneously.

He neither gets caught up in the details nor loses sight of them. He is dissatisfied with both reductionist and holistic views of the brain, and he tries to lay out something in between.

For all I know, Calvin’s view of the brain may even be right. Just as interesting is the view of Calvin’s brain that his book provides.