- seCtIon FoUR: eVoLUtIon
PRoFILe 11.1
Nicholas Humphrey (b. 1943)
As a PhD student in Cam-
bridge, Nicholas Humphrey
discovered, almost by acci-
dent, that monkeys can still
see after their visual cortex
has been removed (the
phenomenon later known
as blindsight). In 1971, during several months at Dian
Fossey’s gorilla research centre in Rwanda, he began
to focus on the evolution of social intelligence, leading
to the idea that human beings are ‘natural psychologists’
who use introspection to model the minds of others. He
convinced Richard Dawkins that memes are living struc-
tures; made a 1980s TV series called The Inner Eye; and
has long worked for the cause of nuclear disarmament.
Returning to Cambridge in 1990 after three years with
Dan Dennett at Tufts, he worked on radically new ideas
about the nature of sensation and qualia, arguing that
sensations are a form of ‘bodily expression’. In Soul Dust:
The Magic of Consciousness, he claims that phenomenal
consciousness is a ‘magical mystery show’ designed by
natural selection to have seemingly ‘out-of-this-world’
properties that make us feel special and transcendent.Consciousness ‘has a survival value in its own right’, says Jeffrey Gray (2004).
He rules out epiphenomenalism, arguing that language, science, and aes-
thetic appreciation would all be impossible without conscious experience,
and that ‘Whatever consciousness is, it is too important to be a mere acci-
dental by-product of other biological forces’ (p. 90). The good fit between
our perceptions of the world and our actions in dealing with it cannot be
an accident and must be under strong selection pressure. Of course, ‘acci-
dental by-product’ and being ‘under strong selection pressure’ are not the
only options, but by assuming they are, Gray can claim that this leaves us
‘with the problem of identifying the causal effects of consciousness in its
own right’ (p. 90).
Gray rejects functionalism (the idea that mental states are functional states),
claiming that synaesthesia (see Chapter 6) provides a counterexample. The colour
qualia that synaesthetes experience, he claims, have no relationship to the word
or number that triggers them and may even interfere with linguistic processing;
and this, he says, is incompatible with functionalism. He argues that qualia are
constructed by a chain of unconscious brain processes and are
only correlated with or ‘attached to’ the functions that give rise
to them; they are not the same as those functions.
Having rejected functionalism, and wanting to ‘creep up’ on
the hard problem, Gray seeks ‘the properties of qualia as
such’ (2004, p. 308). Conscious experience comes too late
to affect rapid ‘on-line’ behaviour, he says, but slowly con-
structs the perceived world, smoothing out the moment-by-
moment confusion to give a semi-permanent appearance.
Since this seems to restrict any ongoing causal efficacy
for consciousness, he concludes that it acts as a late error
detector. An unconscious comparator predicts the next
likely state of the world and compares this with the actual
state. The results of the comparison then ‘enter conscious-
ness’. The hippocampal system is the neural substrate for the
comparator system and ‘so provides conscious experience
with its evolutionary survival value’ (p. 317). This is related
to the earlier proposal of British ethologist John Crook that
‘Consciousness of the world comprises a form of re-presen-
tation of the current perceptual input on a mental screen
so that a constant awareness of a monitoring process arises’
(Crook, 1980, p. 35).These theories give consciousness its own survival value
and function, but do not explain why such monitoring or
error detection requires or entails subjective experience
or ‘creates qualia’ when other brain processes do not. Car-
tesian materialism is implicit in phrases like ‘mental screen’
and ‘entering consciousness’, and there remains a magic
difference between brain processes with qualia ‘attached’
and those without. As Gray admits, he may have crept up on
the hard problem, but he has neither explained it away nor
solved it.‘Consciousness is a
supremely functional
adaptation’
(Baars, 1997b, p. 157)