- seCtIon tWo: tHe BRAIn
PRACTICE 6.1
IS THIS EXPERIENCE UNIFIED?As many times as you can every day, ask yourself, ‘Is this experience
unified?’
You might like to begin, as usual, by asking, ‘Am I conscious now?’ and
then explore what you are conscious of, all the time attending to whether
the experience is unified. You could try this: pay attention to your visual
experience for a few seconds. Now switch to sounds. You will probably
be aware of sounds that have been going on for some time. Has the sight
just become unified with the sound? What was going on before? What role
does attention play in this? You can do the same with verbal thoughts and
bodily sensations. Is your consciousness always unified? Is it now?Since materialism encounters obvious problems too, there are still researchers
who defend versions of mind–body dualism and, despite its ‘bad reputation’,
defend it as part of a ‘progressive research programme’ for exploring all kinds of
questions about consciousness, including its apparent unity (Lavazza and Rob-
inson, 2014, pp. 7, 5). But a more common approach is to try to find out how
the brain and the rest of the body manage to integrate and unify their functions,
and the majority of the examples considered here attempt this. A third and final
approach is to reject the idea that consciousness really is unified at all. Perhaps,
on closer inspection, we might find that the apparent unity is illusory. In this case,
the task is to explain how we can be so deluded.THE BINDING PROBLEM
Take a coin, toss it, and catch it again in your hand. How does this object, the coin,
appear to you as it flies? You might like to toss it a few times and watch carefully.
What do you see?
You will probably see a single object fly up in the air, twist over, and land in one
piece on your hand. Bits don’t fly off. The silver colour doesn’t depart from the
shape, and the shape doesn’t lag behind the motion. But why not?Think now of what is happening in the visual system. Information extracted from
a rich and rapidly changing pattern of excitation in the rods and cones of the ret-
ina takes one route through the superior colliculus to the eye-movement system
and thereby controls your visual tracking of the moving coin. Other information
from the same retinal patterns takes a different route through the lateral genic-
ulate nucleus to visual cortex. In V1 there are many retinotopic maps (that is, the
organisation of cells reflects the layout on the retina), and here the hierarchical
processing of edges, lines, and other basic features begins. Meanwhile, other
visual cortical areas are handling other features, including colour, movement,‘I am one person living
in one world’
(Metzinger, 1995b, p. 427)