Chapter
Three
The grand illusion
PRACTICE 3.1
HOW MUCH AM I SEEING NOW?As many times as you can, every day, ask yourself ‘How much am
I seeing now?’
Whether you are looking at a busy street or a beautiful garden, a page of
text or the back of your own hand, ask How much am I seeing? You may at
first get the impression that you can see everything at once; that there is an
entire, detailed scene in your awareness. Now look again, harder. What
are you actually seeing right now?
If you do this a few hundred times you may be better able to assess the
various theories covered in this chapter. Eventually you may notice some
profound changes. Can you describe what has happened?FIGURE 3.2 • The Café Wall illusion, first
described by Richard Gregory after
seeing tiles on the wall of a café in
St Michael’s Hill in Bristol. When
the tiles are dark and white and
the mortar is thick enough and
mid-tone the horizontal lines do
not look parallel. No attempts to
convince yourself that they are
gets rid of the illusion.There are at least three threads of theory here.
The first is the idea that there is a rich array of
conscious visual impressions to be explained.
The second strand is that at any time there
are definite contents of which we are aware,
while everything else remains ‘outside our
conscious awareness’. This is what Dan Den-
nett (1991) rejects when he claims that there is
no show in the Cartesian theatre, no time and
place where things come on to the stage and
thus become conscious (we will return to this
concept in more detail in Chapter 5). The third
strand is the idea that seeing means having
internal mental pictures; i.e. that the world is
represented in our heads.
All these ideas are combined in concepts like
James’s stream of visual consciousness (1890,
i, p. 245), the ‘movie-in-the-brain’ (Damasio,
1999), or ‘the vivid picture of the world we
see in front of our eyes’ (Crick, 1994, p. 159).
The emphasis placed on the dynamic flow of
experience varies in these metaphors along a spectrum from stream to movie to
picture. In all of them, however, the richness of the experience is unquestioned,
and the in/out distinction and underlying representation tend to be too. The stan-
dard scientific model of vision seems to be built on the same assumptions as the
intuitive account – but maybe both need questioning.
The idea that in seeing (and imagining) we represent the world in our minds goes
back at least as far as the ancient Greeks, who thought about vision in terms of the
world being reflected in the pupil of the eye (and also thought about imagination