On the origin of an essential debate: can science ignore faith?

We are well into the build-up to Darwin200, a series of events that will run throughout 2009, highlighting the 200th anniversary of the birth of Charles Darwin on 12 February and the 150th anniversary of the publication of his magnum opus, On the Origin of Species by Means of Natural Selection, on 24 November.

The Origin is the most important biology book ever written; it sold out on the day it was published, has never been out of print, and has changed for ever the way we see ourselves.

Darwin was more than a little apprehensive about how his theory of evolution by natural selection would be received, realising that it would be controversial. In the event, the reception was generally positive.

Even the established Church of England soon accepted its message, partly because the evidence was overwhelming and the logic of the central argument convincing, and partly, perhaps, because it had little wish to box itself into a corner as the Roman Catholic Church had over Galileo some two centuries earlier. When he died in 1882, Darwin received a state funeral and was buried in Westminster Abbey.

So the short answer to the question "Can science ignore faith?" is "Yes" - and that is what every good scientist does, day in, day out. For all that scientists use a great range of approaches in their work, the cornerstone of science is that any hypothesis, theory or model should be open to empirical testing, and the more rigorous that testing, the more robust the resulting science.

Religious faith, too, uses testable data - but the data are often more subjective; and it also draws on other sources, such as the words of ancestral scriptures or, in many religions, the teachings of a special group of people, such as the magisterium in Roman Catholicism.

However, these important differences between the modus operandi of science and religion do not mean that there is a great gulf between them. For a start, to a religious believer, science is typically an important part of how the world is seen.

Just as the personal universe each of us constructs and inhabits, whether or not we have a religious faith, generally includes such extra-scientific aspects as morality and aesthetics, for religious believers it includes religious faith.

For example, the question of whether there is an afterlife, as conventionally taught in Christianity and a number of other religions, sits outside of science but is a question that may guide much in the life of believers, whether or not they are scientists.

And then there are places where the gap between science and religion is thin. Cosmologists puzzle over the origins of our universe and whether there is but one universe or a near infinity of them, and physicists probe ever more deeply into the fundamental constants whose values permit the evolution of organisms capable of studying such matters.

Many scientists find nothing of religious significance in all this; others find themselves musing over questions of meaning and providence that are close to those considered by philosophers and theologians.

And then, from a rather different angle, evolutionary psychologists reflect on what it was, and still is, in our evolutionary heritage that causes most of humanity to presume the existence of an Almighty. At first sight such reflection might appear to pull the rug out from under the religious believer, but this would be poor reasoning.

The relationship between reality and what humans perceive reality to be is not a straightforward one. Just because religious faith may have an evolutionary explanation does not somehow invalidate it, any more than an evolutionary explanation for language means that we can necessarily ignore a call of "Fire!" or an evolutionary explanation of morality means that virtue does not exist.

So while scientists can safely ignore religion in the routine practice of their work, this does not mean that science and religion can never be in dialogue. Today we still find that many of the issues that preoccupied Darwin occupy our minds. My hope is that Darwin's two anniversaries next year will help us better to examine ourselves in all our complexities and diversities.