I’m very often asked, "What is the Darwinian
survival value of religion?" and I usually
reply, "That may be the wrong question."
You may have to rephrase the question and
it may turn out to be not the survival value
of religion but the survival value of something
else in the brain, which manifests itself
as religion under the right circumstances.
Now, a good analogy which I’ve used is the
question: Why do moths fly into candle flames?
Now, you could describe that behavior as suicidal
behavior in moths, self-immolation behavior
in moths, kamikaze behavior in moths.
That would be one way of phrasing the question,
but it’s the wrong question.
If you actually look at the way moth and insect
eyes generally work, insects use celestial
objects like the sun or the moon or the stars
as compasses.
It’s important, it’s valuable, there is
survival value for any animal moving in a
straight line.
If an animal wants to move in a straight line,
a very good way to do it is to keep a celestial
object at a fixed angle, and that’s easy
to do in insects because they have compound
eyes, very unlike our eyes.
Their eye is a whole sort of hemisphere of
little tubes looking outwards, and so you
can maintain a fixed angle to something like
a star or the moon by keeping the moon in
one ommatidium.
If you do that, because rays from the moon
come from optical infinity, they’re parallel,
and so if you keep of the moon in one ommatidium
you will fly in a straight line.
It might be say 30 degrees; keep the moon
at 30 degrees to your right.
And that works, and that’s valuable, and
that’s what many insects do.
However, candles are not at optical infinity,
candles are close.
The rays of light from a candle are therefore
not parallel, they are radiating out.
If you maintain a fixed angle of say 30 degrees
to the rays that are emitted from a candle
you will describe a neat logarithmic spiral
into the candle flame and kill yourself.
So these moths are not killing themselves,
it’s not suicidal behavior; it’s a misfiring
of a natural, normal behavior, which before
the invention of candles would have worked.
And it still does work the vast majority of
time because most of the time in the dark
a moth is not subjected to artificial light.
So ask the right question.
The right question is not, 'What’s the survival
value of a suicidal behavior in moths?' the
right question is, 'What’s the survival
value of maintaining a fixed angle to a celestial
object?' and then it’s easy to come up with
the right answer.
Proximate questions are questions which you
answer with the physiology of the animal,
the nervous system of the animal, and the
hormones of the animal—things happen in
the animal’s nervous system which cause
it to do something.
That’s the proximal answer.
The ultimate question is, “What’s the
survival value?
What’s the benefit to the animal?
What’s the benefit to the animal’s genes,
in particular, to make it do that?”
An old teacher of mine at Oxford, J.R. Baker,
used the example of breeding seasons in birds.
Why do birds breed at certain times of year?
The ultimate answer is: it’s beneficial
to them to have breeding seasons because they
produce chicks at the right time of year to
cash in on the optimal food supply.
That’s the ultimate answer.
The proximate answer is that they breed at
a certain time of year because day length
is changing and their hormonal system, their
nervous system is geared to day length and
that’s the proximal reason why they breed
at a certain time.
