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“interesting how this fits in with the historical pattern of the epistemological debate. For neither Putnam
nor Davidson nor Dretske propose to challenge the core issues of epistemology directly, but merely
present a convenient escape clause by which philosophers can evade the issue altogether while
supposedly preserving their scientific integrity. This is the same kind of evasion of the fearsome facts of
epistemology as was offered by the dualist account that pushed the problem into the domain of God or
Spirit, and the behaviorist solution that pushed the problem of consciousness off-limits to scientific
scrutiny, and the critical realist solutions that invoke semi-existent spatial entities located in non-space.
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Bertrand Russell, originally himself a critical realist, eventually discovered the resolution to this
quandary with a realist version of Kant’s epistemological dualism. What finally convinced Russell was
consideration of the causal chain of vision. Light from an object in the world enters the eye, where it is
transduced to a neural signal in the optic nerve, from whence it is eventually transformed into a pattern of
activation in the visual cortex. There are two aspects of that perceptual activity, an electrophysiological
aspect measurable by cortical electrodes, and a phenomenal or experiential aspect in the form of the
percept itself. But the two are different manifestations of the same underlying structure, and therefore if
the first is located within the physical brain, then the second must also be in the brain. (Russell 1927 p.
137-143) Russell observed that a potent source of confusion in this matter is a confusion of physical
The Function of Conscious Experience
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space with perceptual space. For although our percept of the external world appears external to our head,
it is not external to our true physical head, but only to our perceptual head in perceptual space. All of our
perceptual space, including the externally perceived world, is inside our physical head in physical space.
(Russell 1927) This explanation of perception finally resolved all of the epistemological problems
inherent in naive realism and in idealism without resort to any supernatural gods or mystical souls. It
accounts for the fact that the perceived world appears external although we know it to be internal, by the
fact that the external world of perception is internal to our physical brain. It accounts for the realism
known to common sense, by the fact that the phenomenal world, while truly internal and shut-in within
the physical brain, nevertheless accurately reflects certain geometrical aspects of the external world,
which is thereby knowable indirectly through its perceptual replica. It accounts for the fact that different
individuals each have their own unique perspective on a commonly viewed object by the fact that each
individual percipient has his own perceptual copy of the commonly viewed object. And it does away
with the incredible proliferation of infinite sets of different perspectives for every object in the world, as
well as with notions of phenomenal sense data which are experienced but which do not or may not
actually exist. Bertrand Russell’s epistemological dualism and causal theory of perception should
therefore have resolved the epistemological question once and for all. But curiously it did not, and the
reason why it has failed to do so is almost as interesting and significant as the epistemological question
itself.
The epistemological debate highlights the very powerful human inclinationhttp://cns-alumni.bu.edu/pub/slehar/webstuff/consc1/consc1a.html (8 of 38) [3/6/2002 12:04:59 PM]
“Why then” asks Gregory “did the Gestalt psychologists choose
isomorphic representation? This is only one of an infinite set of kinds of representation.” The answer, Dr.
Gregory, is to be found by inspection, for the repres
So for example when I stand before a table, the light reflected
from that table into my eye produces an image on my retina, but my conscious experience of that table is
not of a flat two-dimensional image, but rather my brain fabricates a three-dimensional replica of that
table carefully tailored to exactly match the retinal image, and presents that replica in an internal
perceptual space that includes a model of my environment around me, and a copy of my own body at the
center of that environment. The model table is located in the same relation to the model of my body as
the real table is to my real body in external space.
But there is one, and only one entity that we do see directly, and that is
the representational mechanism itself, the inside of our own brain. The volume of space we perceive
around us is a data structure in our physical brain, and the primal color qualia with which that world is
painted are different states of the physical mechanism of our own physical brain.
Epistemological confusion inevitably leads to a confused
philosophy.
Bertrand Russell, originally himself a critical realist, eventually discovered the resolution to this
quandary with a realist version of Kant’s epistemological dualism. What finally convinced Russell was
consideration of the causal chain of vision. Light from an object in the world enters the eye, where it is
transduced to a neural signal in the optic nerve, from whence it is eventually transformed into a pattern of
activation in the visual cortex. There are two aspects of that perceptual activity, an electrophysiological
aspect measurable by cortical electrodes, and a phenomenal or experiential aspect in the form of the
percept itself. But the two are different manifestations of the same underlying structure, and therefore if
the first is located within the physical brain, then the second must also be in the brain. (Russell 1927 p.
137-143) Russell observed that a potent source of confusion in this matter is a confusion of physical
The Function of Conscious Experience
http://cns-alumni.bu.edu/pub/slehar/webstuff/consc1/consc1a.html (8 of 38) [3/6/2002 12:04:59 PM]
space with perceptual space. For although our percept of the external world appears external to our head,
it is not external to our true physical head, but only to our perceptual head in perceptual space. All of our
perceptual space, including the externally perceived world, is inside our physical head in physical space.
(Russell 1927) This explanation of perception finally resolved all of the epistemological problems
inherent in naive realism and in idealism without resort to any supernatural gods or mystical souls. It
accounts for the fact that the perceived world appears external although we know it to be internal, by the
fact that the external world of perception is internal to our physical brain. It accounts for the realism
known to common sense, by the fact that the phenomenal world, while truly internal and shut-in within
the physical brain, nevertheless accurately reflects certain geometrical aspects of the external world,
which is thereby knowable indirectly through its perceptual replica. It accounts for the fact that different
The Lampost Philosopher 