But the distinction between something being non-existent and being other than
it seems is tricky, because once you say something is not what it seems to be, you
may decide you need a new word for it, and so you do end up replacing the old
with the new – that is, declaring that the old thing does not exist. You will notice
these ambiguities popping up in many cases where consciousness, or free will, or
reality, are called ‘illusions’.
Some of the most familiar things that might spring to mind when we think of
illusions are visual illusions. In Figure 3.1, for example, the lines and shapes
really do exist, but the pyramid you see is an illusion: there is something there,
but it’s not a pyramid. Applying the same idea to consciousness, we might say,
as illusionists do, that our experiences exist but consciousness, in the sense that
many people imagine it, does not. It is no coincidence that the science of visual
perception is one of the areas in which the idea of illusion has become most
important. Vision has been more thoroughly studied than any other sensory
modality, and it is also the sense that to many people feels more essential to con-
sciousness than any other: when I think about what it’s like to be me, the visual
experience of looking out and seeing the world may well be the first thing that
comes to mind. Where there is competition between the senses, vision usually
trumps the others, although for people with little or no vision, hearing is often
the most dominant sense from which they construct their understanding of the
world. Finally, vision also has the special status of being more closely associated
with knowledge than any other. Our ordinary language is full of metaphors that
make seeing equivalent to knowing: ‘I see what you mean’, ‘her argument was
crystal clear’, ‘we have looked carefully into the evidence’. These associations
may make it uncomfortable to admit that our visual sense might be misled or
misleading in some way. They also mean that in the case
of vision it is all the more important to consider this pos-
sibility, in case our strong intuitions turn out to be false.
Many familiar illusions, visual and otherwise, may be handy
shortcuts that for many everyday purposes work perfectly
well – like assuming the world is flat when we’re driving, or
that the sun is actually going down when we’re admiring a
sunset. But trying to see things – even things as complex as
vision itself – as they are, rather than as they seem, is crucial
if we want our theories of consciousness to be theories of
what consciousness is actually like rather than what we first
leap to assuming it is like.
So, in this chapter we will take vision as a central example of
how our conscious experience may be subject to illusions,
in the hope that the idea of illusion may be a useful guide
through one part of the labyrinth.
a pitcher and the wash basin – or a corner of the
room with the table and the coat rack – appeared so not-real to me,
despite their indescribable ordinariness, so completely not real, sort of
ghostly, and at the same time provisional, waiting, temporarily taking
‘The term illusion
instantly aligns people’s
thoughts in the wrong
direction’(Graziano, 2016, p. 112)FIGURE 3.1 • Can you see a pyramid? If so, you
are experiencing an illusion. An
illusion is not something that does
not exist, but something that is
not what it appears to be.