Sam Kean’s new book, The Tale of the Dueling Neurosurgeons: The History of the Human Brain As Revealed by True Stories of Trauma, Madness, and Recovery, is a gold mine of stories about the weird things that our brains can make us do, everything from cortical blindness to alien hand and walking dead syndromes. In people with cortical blindness, the eyes and optic nerves work fine, but the portion of the brain that consciously interprets vision is impaired. The brain has a whole separate set of nerves that process the emotional response to vision, however; people with cortical blindness can therefore smile in response to another person’s smile even though they cannot consciously see it. In alien hand syndrome, a person cannot recognize their own hand—usually the left one—as being part of his or her own body; and in walking dead syndrome, the person cannot recognize the body itself as his or her own.
Perhaps
most important, although not the most interesting story in the book, was the
experiment that demonstrated that our brain’s conscious decision to do
something occurred after the subjects
had begun to do the action. That is, the brain’s decision was actually a post-hoc
rationalization. This calls into question the entire concept of free will.
It appears that we choose to do something only after our subconscious minds have decided to do that thing. Of
course, this does not mean we have no conscious control over ourselves. Our
conscious minds can prevent us from doing the things we have started to do;
that is, however much free will is called into question, self-control is certainly real. As the author says, we may not have
free will, but we have free won’t. Also, our conscious minds
can create a general pattern of thought that, while it may not control every individual
action, certainly influences our general behavior.
The
main point of all these fascinating stories is, in the author’s own words: “But
if the history of neuroscience proves anything, it’s that any circuit for any
mental attribute—up to and including our sense of being alive—can fail, if just
the right spots [of the brain] suffer damage…your actions, your desires to act,
and your conviction of having acted can all be decoupled and manipulated.”
I
have, through reading this book, come to understand myself better. Temporal
lobe epilepsy includes the experience of auras that are religious in their
effects and intensity—religious delusions. While religion does not consist only
of delusion, it has been stimulated by delusion. Famous religious figures, such
as the Apostle Paul, Mohammed, and Joan of Arc, and writers such as Dostoevsky
to whom religion was of overwhelming importance, showed symptoms of epilepsy.
Though I do not have epilepsy, I have some symptoms that suggest my right
temporal lobe might be hyperactive in something of the same way as certain
epileptics. For example, throughout my life I have had experiences of religious
ecstasy. I also have to take an anticonvulsant medication that is prescribed,
in higher dosage, to epileptics. And I have a mild case of polygraphia—the
compulsion to write everything down, all day every day—that some epileptics
also have. Finally, there might be a genetic basis for this; my paternal
grandfather was religiously crazy. Somehow just knowing this makes me feel more
comfortable inside my skin.
Kean’s
book, like the books of Mary Roach, show that the best modern science writing
is based on stories and are written to be fun. Filled with fragments and
imprecise language, this book would make some science editors howl, but is
exactly the kind of book that would make anyone want to learn more about science.
This is the kind of science book that I have not yet written myself.
The
feeling I bring away from Kean’s book is liberation. I feel no need to blame
myself for feeling or believing things that may be outrageous, nor do I have to
blame others for theirs. What we need to do is to override anything outrageous
that our minds manufacture. The idea that we choose our beliefs rationally
seems to be entirely wrong, even though reasoning is a contributing factor. As
a scientist and educator, I feel liberation, because I do not need to actually
convince or convert anyone to my way of thinking. What I need to continue doing
is to provide information and opportunity
that will allow my students and my
readers to convert their thinking, should that prove possible. If I continue to
provide information about the world and its history, humans and their history,
and continue provoking new thoughts, I have done my entire job.
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