The death of the brain means subjective experiences are neurochemistry.
Where is the experience of red in your
brain? The question was put to me by Deepak Chopra at his Sages and
Scientists Symposium in Carlsbad, Calif., on March 3. A posse of
presenters argued that the lack of a complete theory by
neuroscientists regarding how neural activity translates into
conscious experiences (such as redness) means that a physicalist
approach is inadequate or wrong. The idea that subjective experience
is a result of electrochemical activity remains a hypothesis, Chopra
elaborated in an e-mail. It is as much of a speculation as the idea
that consciousness is fundamental and that it causes brain activity
and creates the properties and objects of the material world.
Where is Aunt Millie's mind when her
brain dies of Alzheimer's? I countered to Chopra. Aunt Millie was an
impermanent pattern of behavior of the universe and returned to the
potential she emerged from, Chopra rejoined. In the philosophic
framework of Eastern traditions, ego identity is an illusion and the
goal of enlightenment is to transcend to a more universal nonlocal,
nonmaterial identity.
The hypothesis that the brain creates
consciousness, however, has vastly more evidence for it than the
hypothesis that consciousness creates the brain. Damage to the
fusiform gyrus of the temporal lobe, for example, causes face
blindness, and stimulation of this same area causes people to see
faces spontaneously. Stroke-caused damage to the visual cortex region
called V1 leads to loss of conscious visual perception. Changes in
conscious experience can be directly measured by functional MRI,
electroencephalography and single-neuron recordings. Neuroscientists
can predict human choices from brain-scanning activity before the
subject is even consciously aware of the decisions made. Using brain
scans alone, neuroscientists have even been able to reconstruct, on a
computer screen, what someone is seeing.
Thousands of experiments confirm the
hypothesis that neurochemical processes produce subjective
experiences. The fact that neuroscientists are not in agreement over
which physicalist theory best accounts for mind does not mean that
the hypothesis that consciousness creates matter holds equal
standing. In defense, Chopra sent me a 2008 paper published in Mind
and Matter by University of California, Irvine, cognitive
scientist Donald D. Hoffman: Conscious Realism and the Mind-Body
Problem. Conscious realism asserts that the objective world, i.e.,
the world whose existence does not depend on the perceptions of a
particular observer, consists entirely of conscious agents.
Consciousness is fundamental to the cosmos and gives rise to
particles and fields. It is not a latecomer in the evolutionary
history of the universe, arising from complex interactions of
unconscious matter and fields, Hoffman writes. Consciousness is
first; matter and fields depend on it for their very existence.
Where is the evidence for consciousness
being fundamental to the cosmos? Here Hoffman turns to how human
observers construct the visual shapes, colors, textures and motions
of objects. Our senses do not construct an approximation of physical
reality in our brain, he argues, but instead operate more like a
graphical user interface system that bears little to no resemblance
to what actually goes on inside the computer. In Hoffman's view, our
senses operate to construct reality, not to reconstruct it. Further,
it does not require the hypothesis of independently existing physical
objects.
How does consciousness cause matter to
materialize? We are not told. Where (and how) did consciousness exist
before there was matter? We are left wondering. As far as I can tell,
all the evidence points in the direction of brains causing mind, but
no evidence indicates reverse causality. This whole line of
reasoning, in fact, seems to be based on something akin to a God of
the gaps argument, where physicalist gaps are filled with
nonphysicalist agents, be they omniscient deities or conscious
agents.
No one denies that consciousness is a
hard problem. But before we reify consciousness to the level of an
independent agency capable of creating its own reality, let's give
the hypotheses we do have for how brains create mind more time.
Because we know for a fact that measurable consciousness dies when
the brain dies, until proved otherwise, the default hypothesis must
be that brains cause consciousness. I am, therefore I think.
---Michael Shermer, inIn Scientific America, by Michael Shermer, July 1, 2012
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