Reproduced here with permission
Why
am I here? Who am I anyway? Why does everything feel, and look, and hurt
like this? I have been asking questions like this (or they have
been asking me) ever since I can remember. For many years I thought I
could find out by pursuing the paranormal - a fruitless task if ever
there was one. Now the questions seem to converge on one big question
- one that has been called the greatest remaining challenge to science
- what is consciousness?
The
problem of consciousness is real, and deep, and not quite like any
other. I fell happily into it yesterday, walking high on the Devon
cliffs, with the seagulls crying overhead. The grass brushing against
my boots was so - well - grassy. It was green and lush and glistening,
and changing all the time as I strode along. This grassiness was my
experience. Only I had just this vision from just this point of view.
Yet - and here is the problem - I also believe that there is real
green grass growing on that cliff; that I have objectively real eyes
that take in light; and objectively existing brain cells in my head
that make me see. But how can this be? How can objective things like
brain cells produce subjective
experiences like the feeling that ‘I’ am striding through the
grass?
This
gap is what the American philosopher David Chalmers calls ‘the hard
problem’. Victorian thinkers called it the ‘great chasm’ or the
‘fathomless abyss’. It is a modern version of the ancient
mind-body problem - but it seems to get worse, not better, the more we
learn about the brain. Neuroscience is rapidly explaining how brains
discriminate colours, solve problems and organise actions - but the
hard problem remains. The objective world out there, and the
subjective experiences in here, seem to be totally different kinds of
thing. Asking how one produces the other seems to be a nonsense.
This
is what makes the problem of consciousness so interesting - and so
painful. If you don’t find it painful (and I won’t apologise for
wanting you to) pick up any object - a cup of tea or a pen will do -
and just look. Do you believe there is a real cup there? Aren’t you
also having a private subjective experience of the cup? How can this
be? Call me a masochist but I like to induce this kind of pain in
myself many times every day.
The
intractability of this problem suggests to me that we are making a
fundamental mistake in the way we think about consciousness - perhaps
right at the very beginning. So where is the beginning? For William
James - whose 1890 Principles of
Psychology is deservedly a classic - the beginning is our
undeniable experience of the ‘stream of consciousness’; that
unbroken, ever-changing flow of ideas, perceptions, feelings, and
emotions that make up our lives. These thoughts and feelings flow by
and ‘I’ experience them as they pass. This ‘stream’ seems to
be what needs explaining.
But
what if it isn’t like that? What if there is no stream? Can we even
conceive of this possibility? Some recent experimental results suggest
we might have to.
These
experiments reveal what is called ‘change blindness’. Imagine you
are looking at a complex scene - perhaps a street you can see from
your window. You probably imagine that in your stream of consciousness
is a rich and detailed representation of the trees and cars and people
and buildings outside. Many times a second you move your eyes or blink
but the picture seems to stay there. You probably imagine that if
something changed you would notice the difference. You are probably
wrong.
In
change blindness experiments a scene like this is shown to people but,
by using clever eye trackers or other techniques, something in the
picture is changed at the exact moment when they move their eyes. For
example, a tree might disappear, a couple appear on the pavement, or a
car be swapped for a van. In my own experiments, and many others,
people typically fail to detect the change.
This
is weird. If the change is made when their eyes are not moving, people
notice the change immediately. This is because we have special
detectors in
the brain designed to notice objects that move, and draw our attention
to
them. But these detectors can't work when the whole eye moves. If the
change
happens to an object they are directly attending to they notice it
too, but
otherwise it is as if nothing happened.
This
peculiar effect cannot be dismissed as a quirk of lab conditions. Dan
Simons, at Harvard University, showed the same effect in disturbingly
ordinary situations. An experimenter approached a student on the
campus and asked for directions. Meanwhile two men picked up a door
and carried it right between the experimenter and the student as they
talked. Hidden behind the door was a second experimenter who jumped up
and took the place of the first. So now the poor student was talking
to a completely different person. Amazingly, most of the time the
students did not notice the substitution but just went on giving
directions as before.
The
conclusion seems to be this. We do not
have in our heads a rich, stable and detailed visual image of the
world at all. At any time we see in detail only the tiny area we are
looking at. When we move our eyes the detail is all thrown away,
leaving at most a sketchy memory of the scene. We think
it is all in our stream of consciousness because if ever we forget
something we can just look again and there it is. We can use the
outside world as a memory, so our brains don't need to keep the
details. This way we get the illusion that the details are always
there. This alone shows we are wrong about our stream of
consciousness.
This
has been called the ‘Grand Illusion’ theory, but why should we
suffer such an illusion? The answer may simply be that there is too
much information out there for the brain to keep it all (think of how
much computer memory a single picture takes up). But the illusion is
deeper still.
Have
you had this experience? The phone rings, or the clock chimes, several
times before you notice it. At that point you can distinctly count the
number of chimes since it started - chimes you did not consciously
hear. Or what about this? You drive a familiar route, and on arriving
at your destination remember nothing of all those lights you stopped
at, pedestrians you avoided, and decisions you made. Obviously you
were behaving extremely intelligently - otherwise you would be dead -
but somehow ‘you’ were elsewhere - listening to Radio 4 perhaps,
or chatting with a passenger.
At
any point in this journey you might have suddenly woken up, as it
were, and been sure that you had been perfectly conscious for the last
few minutes. The odd occasions are when this doesn’t happen and you
realise how long the blank must have been. This suggests to me that we
live our ordinary lives in a kind of daze. From time to time something
wakes us up. In that moment of awakening the brain concocts, from
memory, a backwards story about what we were just experiencing. A
stream of consciousness and a self who observes it, both appear
together - and both are illusions.
Illusion
is the right word. An illusion is something that exists but is not
what it seems. So the ‘me’ that seems to be steadily experiencing
this world is not nothing, but nor is it the persistent observer with
consciousness and free will that it seems
to be.
How
can I say that ‘I’ am an illusion? Surely I, Sue Blackmore, must
have a self like you do don't I? Well, yes and no. After decades of
thinking about it, funny things happen to the sense of self. Not only
have I struggled with the results of experiments like these, and
practised living without free will, but I have spent a lot of time
sitting still and watching. The harder you look for the self who is
experiencing things, the less obviously it exists. Indeed there can
arise states in which self and other are not separate at all. This is
hard to describe but is obvious when it happens.
I
think we have a long way to go to see through these illusions but this
is what we have to do. We need both to carry out careful experiments,
and to practice looking determinedly into the nature of experience
itself. Perhaps then we won’t see a stream of consciousness and a
self who experiences it, but we’ll see how things really are. Only
then will the hard problem disappear and the fathomless abyss close
up.
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