Richard Dawkins: Why Religion and Evolution Don't Mix Well | Big Think

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 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.