There are many things that humans do that
have nothing to do with contributing to the
survival of the individual, at least nothing
obvious to do with it.
So when we do mathematics and when we do poetry
and when we do ballet dancing and all the
things that make life worth living, it's very
hard to make the case that this contributes
to individual survival; it clearly doesn't.
What you can make a case for is that the possession
of the kind of brain that's capable of doing
those things contributed to individual survival
in our ancestral past.
So it's not the mathematics itself; it's not
that doing algebra helps anybody to survive.
But having the kind of big brain that incidentally
proves itself capable of doing algebra -- having
that kind of big brain probably did improve
our survival, whether because it literally
made us better at -- I don't know -- catching
prey or finding nuts or something of that
sort.
Or whether, in accordance with the sexual
selection theory you just mentioned, it's
attractive to the opposite sex.
This is a theory of a man called Geoffrey
Miller, who is a very interesting evolutionary
psychologist.
And he -- we do have a bit of a puzzle as
to why the human brain did get so big, really
rather suddenly; it's actually one of the
more rapid pieces of evolution that we know.
Over the last three million years or so the
human brain has swelled up enormously.
And there are various theories as to why this
should be.
Geoffrey Miller's theory is that, as you say,
the mind is a kind of human peacock's tail,
and "being clever is sexy" would be one way
to put it.
But it would manifest itself in the ability
to -- I don't know -- remember epic poetry
or something of that sort.
I mean, there are all sorts of different ways
in which, in particular cultures, it might
manifest itself.
