NPR about the experience of consciousness. - Lori]
Any color you choose can be matched by a mixture of short, medium and
long wavelength light (i.e., blue, green and red light). This
perceptual observation led to the formulation, early in the 19th
century, of a neurophysiological hypothesis: The eye contains three
kinds of distinct color-sensitive receptors (cones); just as colors
themselves can be composed of lights of different spectral character, so
we can see the vast range of visible color thanks to the joint
operation of only three distinct kinds of receptors.
This is a
beautiful example of the primacy of experience in the study of the
brain-basis of consciousness. Before you can even begin to think about
how the brain enables us to see or feel or (more generally) experience
what we do, you need to pay careful attention to what our experience is
And, so, it was further attention to the
experience that led scientists to realize the shortcomings of what came
to be known as the Trichromatic Theory of Color.
Consider: You get purple by mixing blue and red light. Indeed, purple
is just a reddish-blue or a bluish-red; you can actually see the red
and blue in the purple, and you can imagine a purple becoming more and more blue until it is entirely blue.
Trichromatic Theory tries to explain these phenomena by suggesting that
we see purple when our red and blue sensitive cones (that is, our long
wave- and short wave-sensitive cones) are activated at the same time.
Different purples correspond to different ratios of activation.
now, consider the case of yellow. You get yellow by mixing red and
green light, just as you get purple by mixing red and blue. But yellow
isn't reddish-green or greenish-red in the way that purple is
reddish-blue. In fact, there is no such thing as reddish-green.
Moreover, you don't see red or green in yellow the way you see blue and red in purple. Yellow, like blue and red, but not like purple, is unary, not binary.
Trichromatic Theory has no resources to explain facts about color
vision such as these. In order to explain them, neurophysiologists were
led to propose a totally different kind of theory of neural processing
beyond the retina (the so-called Opponent Processing Theory).
speak of the primacy of experience in order to bring out the fact that
an investigation of what we see — a careful reflection on rules
governing our experience — is a necessary preliminary to the
neurophysiological study of how neural states support and enable
But how do we study experience? How do we carry out what is sometimes, in philosophical circles, called phenomenology?
are three kinds of obvious obstacle. First, most of the time, in daily
life, we aren't interested in experience itself. We are interested not
so much in the experience of color, for example, as in such things as
whether the tomato is ripe, or whether you should paint your living room
this shade of off-white rather than one of the half-dozen other shades
for sale at the same hardware store. Paying attention to experience
requires new skills, or at least new habits.
Second, so often
when you do turn your attention to your experience, you change the
experience. When was the last time you compared the way your sweater
looks in different conditions of illumination? If you were to do that
you'd probably notice features that had never been brought to your
attention before. Have you better appreciated how your sweater really
looks? Or do you now experience it differently?
attitudes about experience are usually governed by familiar concepts,
and those familiar concepts don't really do justice to the great variety
we actually experience. Take that red car parked out front. You see it.
It's red. You experience its color. But there is so much more
to be said about how it looks, even just confining our attention to
color, than merely that it looks red. At one end it is glowing white in
the direct glare of the sun. At the other end it is bathed in cool
shadow and looks, really, almost gray. Gaining access to the structure
and quality of experience requires, it would seem, a better taxonomy of
qualities and modes of awareness of those qualities. It isn't obvious
that ordinary language and thought provide us with this superior
One of the extraordinary and exciting claims advanced in Evan Thompson's new book Waking, Dreaming, Being
is that some meditative practices — for example the sorts of focused
attention practices developed in some Buddhist traditions — can actually
be thought of as techniques for attending to features of
experience to which we usually pay no attention. Like artists and
designers who learn to notice and see what most of us tend to ignore or
neglect, adept meditators can see and notice things we rarely ever do.
For this reason, if Thompson is right, these expert practitioners can
play a special role not as guinea pigs, but as collaborators in the
development of a better, more adequate neuroscience of human experience. Read More