[ExI] Frank Jackson's brilliant color scientist Mary

John Clark johnkclark at gmail.com
Sun Dec 22 17:54:58 UTC 2019

Philosopher Frank Jackson believed existing physics could not explain
everything about conscious experience and in 1982 he proposed a thought
experiment that he thought would prove it. Jackson said:

"*Mary is a brilliant scientist who is, for whatever reason, forced to
investigate the world from a black and white room via a black and white
television monitor. She specializes in the neurophysiology of vision and
acquires, let us suppose, all the physical information there is to obtain
about what goes on when we see ripe tomatoes, or the sky, and use terms
like 'red', 'blue', and so on. She discovers, for example, just which
wavelength combinations from the sky stimulate the retina, and exactly how
this produces via the central nervous system the contraction of the vocal
cords and expulsion of air from the lungs that results in the uttering of
the sentence 'The sky is blue'. […] What will happen when Mary is released
from her black and white room or is given a color television monitor? Will
she learn anything or not? It seems just obvious that she will learn
something about the world and our visual experience of it. But then is it
inescapable that her previous knowledge was incomplete. But she had all the
physical information. Ergo there is more to have than that, and Physicalism
is false.*"

Mary does indeed gain new knowledge when she steps out of the room and sees
the color red for the first time, her brain already had the right synaptic
connections to correctly answer all  questions about the physics of color,
when she actually sees red for the first time that means the neurons in the
visual cortex of her brain have been rearranged in a way they never have
been before, that is to say memories of having seen red are formed for the
first time; so Mary now has memories she didn't previously have and thus
can do something she couldn't do before, recognize red objects by sight.
New knowledge gives us the ability to do things we couldn't do before.

So all this thought experiment shows is that there are 2 types of
synaptic connections, one type that happens by reading books about the
physics and physiology of color and another type caused by stimulating the
visual cortex of the brain. Mary didn't even need to leave the room to do
all this, after all she is suposed to know all there is to know about color
so she could have drilled a hole in her skull inserted a probe and directly
stimulated the neurons in her visual cortex.

By 2003 even Jackson could see the logic in this argument and admitted he
was wrong,  he now thinks existing physics can explain qualia after all. He

"*Most contemporary philosophers given a choice between going with science
and going with intuitions, go with science. Although I once dissented from
the majority, I have capitulated and now see the interesting issue as being
where the arguments from the intuitions against physicalism—the arguments
that seem so compelling—go wrong**"*

John K Clark
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