Consciousness

• seCtIon FoUR: eVoLUtIon

FoUR WAYs oF tHInKInG

ABoUt tHe eVoLUtIon oF

ConsCIoUsness

1 Conscious inessentialism

(epiphenomenalism)

Zombies are possible. In principle, there

could be creatures that look and act exactly

like us but are not conscious. Consciousness

is separable from adaptive traits such as

intelligence, language, memory, and prob-

lem-solving, but it makes no detectable dif-

ference (this is the definition of a zombie)

and has no effects (this is epiphenomenal-

ism). For this approach, the important (and

mysterious) question is, ‘Why did evolution

produce conscies instead of zombies?’

2 Consciousness has an

adaptive function

Zombies are not possible because having

consciousness makes a difference. It is separable from

evolved adaptive traits such as intelligence, language,

memory, and problem-solving, and adds something

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11.1

FIGURE 11.2 • What has left this rabbit? Is it
a life force or élan vital? Now
that we understand how life
perpetuates itself this concept
is not needed. Will the idea of
consciousness go the same way?

evolve out of unconscious matter? William James, a pio-

neer of evolutionary psychology, explained the central

problem.

The point which as evolutionists we are bound to

hold fast to is that all the new forms of being that

make their appearance are really nothing more

than results of the redistribution of the original and

unchanging materials. The self-same atoms which, chaotically dispersed,

made the nebula, now, jammed and temporarily caught in peculiar

positions, form our brains; and the ‘evolution’ of the brains, if understood,

would be simply the account of how the atoms came to be so caught and

jammed. [. . .] But with the dawn of consciousness an entirely new nature

seems to slip in.

(1890, i, p. 146)

James set himself the task of trying to understand

how consciousness could ‘slip in’ without recourse

to a mind-stuff, mind-dust, or soul. This is essentially

the task we face today, but we should not confuse it

with two other related questions. The first concerns

when consciousness arises during human develop-

ment. For example, is an unfertilised egg or a human

foetus conscious? And if not, when does a baby or

a child become conscious? The second (Chapter 10)

concerns which creatures alive today are conscious.

Answers to these may, or may not, help us with the

question at issue here: when did consciousness first

evolve?

Over this question there is strong disagreement.

Some believe that its appearance was gradual, such

as Susan Greenfield, who claims that ‘consciousness

is not all-or-none but comes in degrees’, increas-

ing like a dimmer switch with increasing brain size

(Greenfield, 2000, p. 176). Others think quite the

reverse. ‘One thing of which we can be sure is that

wherever and whenever in the animal kingdom con-

sciousness has in fact emerged, it will not have been

a gradual process’ (Humphrey, 2002, p. 195).

Some place its arrival very early. For example,

panpsychists believe that everything is conscious,

although the consciousness of stones and streams

is much simpler than that of slugs and sea lions. On

this view, consciousness itself came long before

biological evolution began, but the kind and com-

plexity of consciousness might still have evolved.

Some believe that life and consciousness are insep-

arable, so that as soon as living things appeared on

earth, approximately four billion years ago, there

‘with the dawn of

consciousness an

entirely new nature

seems to slip in’

(James, 1890, i, p. 146)

‘consciousness is not

all-or-none but comes in

degrees’

(Greenfield, 2000, p. 176)

‘it will not have been a

gradual process’

(Humphrey, 2002, p. 195)