CHAPTER

The function of consciousness

eLeVen

CONSCIOUSNESS IN EVOLUTION

Evolutionary theory is especially good at answering ‘why’ questions. Why are

leaves flat and green? So they can photosynthesise efficiently. Why do cats have

fur? To keep them warm. Why do birds have wings? So they can fly. Why are we

conscious? So we can. . .

It is easy to think that since humans are conscious, consciousness itself must have

a function and be adaptive. Nicholas Humphrey makes this sound obvious: ‘either

we throw away the idea that consciousness evolved by natural selection, or else

we have to find a function for it’ (Humphrey, 1987, p. 378). He says ‘we can take it

for granted that – like every other specialized feature of living organisms – it has

evolved because it confers selective advantage’ (2011, p. 14). If he is right, we have

to discover what that selective advantage was.

But the connection between consciousness and evolution may not be so simple.

Evolved traits are not necessarily adaptive traits, and there are other options. The

field of evolutionary psychology can help us think more clearly about how and

why the human mind has evolved the way it has, but its history has been a con-

troversial one.

The principles of evolution apply as much to human beings as to slugs and beet-

root plants, yet resistance to this idea has always been strong. At the end of The

Origin of Species, Darwin suggested that ‘Much light will be thrown on the origin

‘the story of the

emergence of

consciousness seems

to remain in medieval

darkness’

(Dehaene, 2014, p. 7)

‘Either we throw

away the idea that

consciousness evolved

by natural selection, or

else we have to find a

function for it’

(Humphrey, 1987, p. 378)