While it is true that there are a number of theories in circulation
currently about the nature of consciousness, though I think things have
moved on a quite bit since the quotes Robert gives were written 10+ years
ago. Anyway, even if there is not yet a standardized scientific theory out
yet, this does not mean that consciousness is not an intractable problem.
Since it is part of the physical universe, it should eventually be amenable
to explanation -- it may be mysterious but not mystical. Note here that I
am not taking a reductionist view with regards to what I would consider to
be purely spiritual matters.
That the mind is dependent upon the brain seems to be corroborated by the
evidence that can be garnered from people with brain disorders, whether due
to accident or congenital. One analogy that seems fitting is the idea that
the brain is like a radio transmitter-receiver. That is to say, it can
generate radio waves and receive them, but the waves themselves can survive
for great lengths of time outside the equipment although probably degrading
into an eventual state of entropy. Perhaps that is what Nirvana is --
entropy :)