- seCtIon tWo: tHe BRAIn
experience we will never know what is it like to be a patient
affected by unilateral neglect’ (1988, p. 117). But perhaps we
already do. Our eyes and ears detect only a small range of
wavelengths; we have no electrical sense like some fish nor
infra-red detectors like some snakes. From the richness of the
world out there, our senses select what they are evolved to
select, and the rest we do not miss and cannot even imag-
ine. This is why Metzinger (2009) describes us as living in a
tunnel. In this sense, we all live our lives in a profound state
of neglect.
Other examples that challenge the unity of consciousness
include out-of-body and near-death experiences, in which
consciousness seems to split from the physical body (Chapter 15); and medium-
ship, trances, and hypnosis (Chapter 13), in which consciousness can seem to be
divided. Although many people assume that consciousness is necessarily unified
most of the time, there are plenty of reasons for doubt.It always seems to me that our ordinary consciousness inhabits
the tip of a pyramid whose base extends so widely within us
(and to a certain extent under us) that the further we think
we’re able to let ourselves sink into it, the more wholly we seem
encompassed by the timeless and spaceless givenness of earthly,
in the broadest sense worldly, existence. Since my youth I have
always suspected [. . .] that in a deeper section of this pyramid
of consciousness, simple existence could become an event –
that unbreakable presentness and simultaneity of everything
which at the ‘normal’ pinnacle of self-consciousness can only be
experienced as ‘sequence’.(Rainer Maria Rilke (1980), letter to Nora Purtscher-Wydenbruck,
11 August 1924, our translation)UNITY IN TIME
We tend to feel not only that everything comes together ‘in’ our conscious expe-
rience, but that it happens now, and we may think that the now of our conscious-
ness is the same as the now of the world we’re perceiving; we don’t need to ask
ourselves ‘when is now?’ or what it means to say that there is a time at which
conscious experiences happen. But some experiments challenge these simple
intuitions.
Clock time and experienced time are not the same thing. While events in the
external world can be timed with clocks, as can events happening inside the
brain (such as neurons firing), perceived time is not like this. We can only find
out about it by asking a person to report in some way. This is notoriously dif-
ficult, as we will find out in Chapter 9, when we look at Libet’s famous exper-
iments on apparent time lags in both conscious sensation and willed action.FIGURE 6.13 • Two drawings made by a patient
suffering from unilateral neglect,
studied by Marshall and Halligan
(1988). The drawing on the left
was done in the acute phase after
the stroke, while the one on the
right was drawn in the chronic
phase several months later.
FIGURE 6.14 • Figure used to investigate covert
processing in a patient with hemi-
neglect of the left half of the visual
space. The two figures looked
identical to the patient because only
their right halves were reported as
seen. Nevertheless, when required to
indicate which house she would prefer
to live in, she chose the bottom one,
although she said she was guessing
(Marshall and Halligan, 1988).