(posted on 18-Dec-2000)
A short addition to Pierre's post.
Thinking is tough to quantify
because it's entirely subjective. That is, we only know about someone
else's thoughts if they tell us about them. There're still many unknowns
in the area, but breakthroughs with new data seem to be happening every few
weeks.
So how do we know that thoughts are produced by the
brain?
(1) The earliest clues came from brain damaged people. If a
certain part of the brain is damaged or destroyed, we lose specific
abilities. Sachs writes a lot about such cases, damage cause by strokes,
car wrecks, etc. and how it changes the lives of patients. You can
actually predict with fair accuracy what abilities a person will lose if
you know what part of the brain is damaged. More importantly, trauma can
easily produce personality changes and other effects that would not happen
if thought or personality existed outside of the brain cells. Nerve cells
don't regenerate, but sometimes the brain reroutes around the damaged area
and the person returns to normal. Again, a very definite correlation
between brain cells and personality/thoughts.
(2) Brain surgeons
accidentally discovered that if they touched areas of the brain with
electricity, it stimulated memories, smells, body sensations, etc. Again,
specific areas of the brain produce specific effects. There is a definite
1-1 correlation between brain cell stimulation and subjective experiences,
as reported by patients.
(3) New technology allows us to see the
brain at work, the actual increase in electrical and chemical activity.
Researchers ask subjects to perform a task, like working a math problem,
then map the brains as they work. How do we know that the brain cell
activity is not a side effect of thought rather than the producer of
thought? Because cell activity begins before the thoughts do. For
example, if you look at your right thumb and decide to move it, your brain
has already sent the signal to the thumb before the "you" that processes
information decides to move it.
That inner voice that we think of
as "us" is actually a construct of many simultaneous brain activities.
It's sort of like the operating system in a computer. Many programs are
running at the same time, but the "user" only sees the important things.
When the brain crashes, due to fever, starvation, trauma, intoxication,
etc., the "user" program is the first one to malfunction and we experience
some of the background programs in a disorganized fashion.
Many
religions encourage their members to experience being conscious but seeing
behind the "user" program. They do this by sensory depravation (extreme
mediation), starvation, exhaustion, and other ways to stress the body to
the point where brain chemistry is messed up, but the person is still
conscious. From this experience, we get the idea of life being an illusion
(the "user" program) while the "real" events can only be experienced by
muting the "self"
And so on.
So where we are now in research
is that we have several definite physical connections between the brain and
thought production but not a single verifiable example of thought existing
without a physical brain. If you with the preponderance of evidence,
thought is produced by the brain.
Fred Askew
Lynn's original question:
Someone asked that question ("who is the thinker of my thoughts?"), and it started me wondering...Has science actually proved the human brain is capable of thought and where said thoughts originate? I know the chemical reactions between the cells have been mapped and monitored, and specific areas of actions have been ID'd, but has science actually PROVED THOUGHT exists, and what it is that originates the thought?
Lynn
Pierre's response:
Hi Lynn,
Science doesn't quite do things the way your question
suggests but it is still a wonderful question. Let me give you a superb
reference to go with the question rather than a response here which could
not begin to cover the ground. If you can get this book, The Man Who
Mistook His Wife For a Hat
by Dr. Oliver Sachs (a review as well as
ordering info appear if you click on the preceding link) it will go a long
way, a VERY long way towards answering the question.
Science has
done a lot (so much it would encompass a huge library building to store it)
to link specific thinking to the brain. If you can get past your
traditional bias of souls and spirits about which nothing much is known
except anecdotes of doubtful usefullness and really want some insight into
what actually goes on, I suggest some readings into how PET (positron
emission tomography) scans work and what they do-- which is to localize the
areas of the brain which are working during particular activities including
thinking and problem solving. I am sure there are some writings which are
not very technical yet are informative.
But give Dr. Sachs a try--
he is funny, casual, and while he keeps it non-technical, he does not write
down to the reader.
I am sure others will have many more
suggestions.
Link URL for The Man Who Mistook His Wife For a
Hat by Dr. Oliver
Sachs:
http://www.bookideas.com/reviews/nonfiction/wifehat.htm
Pierre