last great mystery of science”; “the most baffling problem in the
science of the mind”; this is how scientists talk about
consciousness, but what if our conscious experience is all a grand
Like most people, I used to think of my conscious life as like a
stream of experiences, passing through my mind, one after another. But
now I’m starting to wonder, is consciousness really like this? Could
this apparently innocent assumption be the reason we find
consciousness so baffling?
Different strands of
research on the senses over the past decade suggest that the brave
cognitive scientists, psychologists and neuroscientists who dare to
tackle the problem of consciousness are chasing after the wrong thing.
If consciousness seems to be a continuous stream of rich and detailed
sights, sounds, feelings and thoughts, then I suggest this is the
First we must be clear what
is meant by the term “illusion”. To say that consciousness is an
illusion is not to say that it doesn’t exist, but that it is not
what it seems to be―more like a mirage or a visual illusion. And
if consciousness is not what it seems, no wonder it’s proving such a
For the proposal “It’s all an illusion” even to be worth
considering, the problem has to be serious. And it is. We can’t even
begin to explain consciousness. Take this magazine in front of your
eyes. Right now, you are presumably having a conscious experience of
seeing the paper, the words, and the pictures. The way you see the
page is unique to you, and no one else can know exactly what it is
like for you. This is how consciousness is defined: it is your own
But how do you get from a magazine composed of atoms and molecules, to
your experience of seeing it? Real, physical objects and private
experiences are such completely different kinds of thing. How can one
be related to the other? David Chalmers, of the University of Tucson,
Arizona, calls it the “Hard Problem”. How can the firing of brain
cells produce subjective experience? It seems like magic; water into
If you are not yet feeling perplexed (in which case I am not doing my
job properly), consider another problem. It seems that most of what
goes on in the brain is not conscious. For example, we can consciously
hear a song on the car radio, while we are not necessarily conscious
of all the things we do as we’re driving. This leads us to make a
fundamental distinction: contrasting conscious brain processes with
unconscious ones. But no one can explain what the difference really
is. Is there a special place in the brain where unconscious things are
made conscious? Are some brain cells endowed with an extra magic
something that makes what goes on in them subjective? This doesn’t
make sense. Yet most theories of consciousness assume that there must
be such a difference, and then get stuck trying to explain or
For example, in the currently popular “Global Workspace” theory,
Bernard Baars, of the Wright Institute in Berkeley, California,
equates the contents of consciousness with the contents of working
memory. But how does being “in” memory turn electrical impulses
into personal experiences?
Another popular line of
research is to search for the “neural correlates” of
consciousness. Nobel Laureate, Francis Crick, wants to pin down the
brain activity that corresponds to “the vivid picture of the world
we see in front of our eyes”. And Oxford pharmacologist, Susan
Greenfield, is looking for “the particular physical state of the
brain that always accompanies a subjective feeling” (New
Scientist, 2 Feb, p 30). These researchers are not alone in their
search. But their attempts all founder on exactly the same
mystery―how can some kinds of brain activity be “in” the
conscious stream, while others are not? I can’t see what this
difference could possibly be.
Could the problem be so serious that we need to start again at the
very beginning? Could it be that, after all, there is no stream of
consciousness; no movie in the brain; no picture of the world we see
in front of our eyes? Could all this be just a grand illusion?
You might want to protest. You may be absolutely sure that you do have
such a stream of conscious experiences. But perhaps you have noticed
this intriguing little oddity. Imagine you are reading this magazine
when suddenly you realise that the clock is striking. You hadn't
noticed it before, but now that you have, you know that the clock has
struck four times already, and you can go on counting. What is
happening here? Were the first three “dongs” really unconscious
and have now been pulled out of memory and put in the stream of
consciousness? If so were the contents of the stream changed
retrospectively to seem as though you heard them at the time? Or what?
You might think up some other elaborations to make sense of it but
they are unlikely to be either simple or convincing.
A similar problem is apparent with listening to speech. You need to
hear several syllables before the meaning of a sentence becomes
unambiguous. So what was in the stream of consciousness after one
syllable? Did it switch from gobbledegook to words half way through?
It doesn't feel like that. It feels as though you heard a meaningful
sentence as it went along. But that is impossible.
Consciousness also does funny things with time. A good example is the
“cutaneous rabbit”. If a person’s arm is tapped rapidly, say
five times at the wrist, then twice near the elbow and finally three
times on the upper arm, they report not a series of separate taps
coming in groups, but a continuous series moving upwards―as
though a little creature were running up their arm. We might ask how
taps two to four came to be experienced some way up the forearm when
the next tap in the series had not happened yet. How did the brain
know where the next tap was going to fall?
You might try to explain it by saying that the stream of consciousness
lags a little behind, just in case more taps are coming. Or perhaps,
when the elbow tap comes, the brain runs back in time and changes the
contents of consciousness. If so, what was really in consciousness
when the third tap happened? The problem arises only if we think that
things must always be either "in" or "out" of
consciousness. Perhaps, if this apparently natural distinction is
causing so much trouble, we should abandon it.
Even deeper troubles threaten our sense of conscious vision. You might
be utterly convinced that right now you're seeing a vivid and detailed
picture of the world in front of your eyes, and no one can tell you
otherwise. Consider, then, a few experiments.
The most challenging are studies of “change blindness” (New
Scientist, 18 Nov 2000, p 28). Imagine you are asked to look at
the left hand picture in the illustration below. Then at the exact
moment you move your eyes (which you do several times a second) the
picture is swapped for the one on the right. Would you notice the
difference? Most people assume that they would. But they'd be wrong.
When our eyes are still we detect changes easily, but when a change
happens during an eye movement or a blink we are change blind.
Another way to reveal change blindness is to present the two pictures
one after the other repeatedly on a computer screen with flashes of
grey in between (for an example see
http://nivea.psycho.univ-paris5.fr/ASSChtml/kayakflick.gif). It can
take people many minutes to detect even a large object that changes
colour, or one that disappears altogether, even if it’s right in the
middle of the picture.
What do these odd findings mean? At the very least they challenge the
textbook description that vision is a process of building up
representations in our heads of the world around us. The idea is that
as we move our eyes about, we build up an even better picture, and
this picture is what we consciously see. But these experiments show
that this way of thinking about vision has to be false. If we had such
a picture in our heads we would surely notice that something had
changed, yet we don't. We jump to the conclusion that we’re seeing a
continuous, detailed and rich picture. But this is an illusion.
Researchers differ in how far they think the illusion goes.
Psychologists Daniel Simons of Harvard University and Daniel Levin of
Kent State University, Ohio, suggest that during each visual fixation
our brain builds a fleeting representation of the scene. It then
extracts the gist and throws away all the details. This gives us the
feeling of continuity and richness without too much overload.
Rensink of the University of British Columbia in Vancouver, goes a
little further and claims that we never form representations of the
whole scene at all, not even during fixations. Instead we construct
what he calls “virtual representations” of just the object we are
paying attention to. Nothing else is represented in our heads, but we
get the impression that everything is there because a new object can
always be made “just in time” whenever we look.
Finally, our ordinary notions of seeing are more or less demolished by
psychologists Kevin O'Regan of the CNRS, the French national research
agency in Paris, and Alva NoŽ of the University of California, Santa
Cruz, who first described vision as a grand illusion. They argue that
we don't need internal representations at all because the world is
always there to be referred to. According to their “sensorimotor
theory of vision” seeing is not about building pictures of the world
in our heads, it’s about what you are doing. Seeing is a way of
interacting with the world, a kind of action. What remains between eye
movements is not a picture of the world but the information needed for
further exploration. The theory is dramatically different from
existing theories of perception.
It’s not clear who’s right. Perhaps all these theories are off the
mark, but there is no doubt about the basic phenomenon and its main
implication. Searching for the neural correlates of the detailed,
picture in our heads is doomed because there is no such picture.
leaves another problem. If we have no picture, how can we act on the
things we see? This question may seem reasonable but it hides another
false assumption―that we have to see consciously in order to
act. We need only think of the tennis player who returns a serve
before consciously seeing it, to realise that this is false, but the
situation is odder than this. We probably have several separate visual
systems that do their jobs somewhat independently, rather than one
single one that produces a unified visual world.
David Milner of the University of St Andrews, and Melvyn Goodale of
the University of Western Ontario, argue that there is one system for
fast visuomotor control and a slower system for perceiving objects.
Much of their evidence comes from patients with brain damage, such as
D.F. who has a condition known as visual form agnosia. She cannot
recognise objects by sight, name simple line drawings, or recognise or
copy letters, even though she produces letters correctly from
dictation and can recognise objects by touch. She can also reach out
and grasp everyday objects (objects that she cannot recognise) with
remarkable accuracy. D.F. seems to have a visual system that guides
her actions but her perception system is damaged.
In a revealing experiment D.F. was shown a slot set randomly at
different angles. (Trends in Neurosciences, vol 15 p 20, 1992).
She could not consciously see the orientation of the slot, and could
not draw it or adjust a line to the same angle. But when given a piece
of card she could quickly and accurately line it up and post it
straight through. Experiments with normal volunteers have shown
similar kinds of dissociation, suggesting that we all have at least
two separate vision systems.
Perhaps the most obvious conclusion is that the slow perceptual system
is conscious and the fast action system is unconscious. But then the
old mystery is back. We would have to explain the difference between
conscious and unconscious systems. Is there a magic ingredient in one?
Does neural information turn into subjective experiences just because
it is processed more slowly?
Perhaps the answer here is to admit that there is no stream of
conscious experiences on which we act. Instead, at any time a whole
lot of different things are going on in our brain at once. None of
these things is either “in” or “out” of consciousness but
every so often, something happens to create what seems to have been a
unified conscious stream; an illusion of richness and continuity.
It sounds bizarre, but try to catch yourself not being conscious. More
than a hundred years ago the psychologist William James likened
introspective analysis to “trying to turn up the gas quickly enough
to see how the darkness looks." The modern equivalent is looking
in the fridge to see whether the light is always on. However quickly
you open the door, you can never catch it out. The same is true of
consciousness. Whenever you ask yourself, “Am I conscious now?”
you always are.
But perhaps there is only something there when you ask. Maybe each
time you probe, a retrospective story is concocted about what was in
the stream of consciousness a moment before, together with a
“self” who was apparently experiencing it. Of course there was
neither a conscious self nor a stream, but it now seems as though
Perhaps a new story is
concocted whenever you bother to look. When we ask ourselves about it,
it would seem as though there’s a stream of consciousness going on.
When we don't bother to ask, or to look, it doesn't, but then we don't
notice so it doesn't matter.
Admitting that it’s all an illusion does not solve the problem of
consciousness but changes it completely. Instead of asking how neural
impulses turn into conscious experiences, we must ask how the grand
illusion gets constructed. This will prove no easy task, but unlike
solving the Hard Problem it may at least be possible.
Blackmore is a psychologist, writer and lecturer based in Bristol.