Soul DustThe Magic of ConsciousnessNicholas HumphreyPrinceton
University Press, $24.95, 256 pp. When I discuss the scientific
study of human consciousness with my general-education students,
I begin by introducing them to a field-monitoring device used by
a colleague in Environmental Studies. It stands three feet high
and continually records temperature, relative humidity,
precipitation, barometric pressure, wind speed and direction,
and sun intensity. I ask my students, when it’s raining, does
this device know it’s raining? Quickly they recognize that it
doesn’t. So, I continue, how could you modify it so that it does
know when it’s raining? Not just modify it so that it responds,
zombie-like, to the rain—by putting on a hat, say—but so that it
is conscious of the rain? For this question they have no answer,
and with good reason. This is known in consciousness studies as
“the hard problem.” How can matter be put together in such a way
that it can become conscious of the world? Philosophers have
long asked th