- seCtIon tHRee: BoDY AnD WoRLD
other words, they think that intervention by the nonphysical mind is required to
explain subjective antedating. On their view, Libet’s results provide evidence for
dualism – a claim that others firmly reject (e.g. Churchland, 1981; Dennett, 1991).
Despite his belief in a mental force, Libet himself points out that subjective referral
in space has long been recognised and so we should not be surprised to find sub-
jective referral in time as well. Although it may seem odd that we experience objects
as ‘out there’ when vision depends on our brain ‘in here’, this kind of projection is not
magical, he says – and nor is subjective referral. Given the widely dispersed activity
in the central nervous system, we should expect a mechanism that coordinates
subjective timings. Subjective referral to the evoked potentials does just that.
Let’s return to our scenario from Chapter 7, about turning to look at the person
coming into the room. Which comes first, the movement to see who it is, or
the awareness? If Libet is right, then conscious perception of the noise cannot
occur unless there is at least half a second of continuous neural activity after the
noise begins. Since we often react far faster than that, this means that the causal
sequence cannot be 1) consciously hear sound, and 2) turn round to look.
The previous paragraph was carefully worded. It said that conscious perception
cannot occur unless there is at least half a second of continuous neural activity
after the noise begins – which is indeed suggested by Libet’s results. What is not
necessarily implied, though it is often assumed, is something like this: after the
noise occurs there is a lot of unconscious processing. Then, after half a second,
the noise ‘becomes conscious’ or comes ‘into consciousness’. At that point, it is
antedated so that it seems to have occurred earlier, at the right time. On this view,
consciousness really does trail along half a second behind the events of the real
world, but we don’t realise it.The difference between these two descriptions is important. The first doesn’t
commit to a time at which consciousness happens or emerges. The second does:
it assumes there is a fact of the matter about when processing becomes conscious
In Chapter 6, we considered the distinction between clock time and perceived
time, and reviewed reasons to question the very idea that there is a measurable
time at which subjective experience happens. This means we should also ques-
tion Libet’s view that the experience itself can be timed, and that consciousness
happens when neuronal adequacy is achieved. In any case, the findings from
Libet’s experiments on the timing of consciousness remind us to pay careful
attention to timing when we ask whether and how consciousness contributes to
‘freely willed’ action.THE ROLE OF CONSCIOUS WILL
IN VOLUNTARY ACTION
Hold out your hand in front of you. Now, whenever you feel like it, consciously,
deliberately, and of your own free will, flex your wrist. Keep doing this for some
time – until your arm gets too tired. Just flex your wrist whenever you want, and
try to observe what goes through your mind as you do so. If you don’t want to do
it at all that’s fine – that is your conscious decision. If you want to do it frequently,
that is fine too. Now ask yourself what started the movement, or prevented it,
each time. What caused your action?