Writing an epitaph for a God who can rise from the dead is a risky business. However, falling church attendances and the increasing secularisation of society indicate that the Western Christian concept of God is becoming more untenable in our age of science and reason. The irony is that the very concept of God which science is currently slaying is one which is largely of its own making.

It is fitting that a physicist, Blaise Pascal, was one of the first thinkers seriously to entertain the possibility that God might not exist. For Pascal, belief in God could only be based on personal religious experience rather than rational belief. He said: "We are incapable of knowing either what God is or whether he is . . . Reason cannot decide this question."

Pascal was happy to restrict his faith in reason to his scientific pursuits, and embraced a belief in God. Had his position found more widespread acceptance, Christianity today would hold a different view of God than is the case. However, the Christian concept of God has undergone a radical revision since Pascal, largely as a result of the scientific revolution.

Beginning with Descartes, the Western idea of God came to rely more and more on the belief that the rational mind is capable of discovering God. Natural theology - the ability to find proof of God's existence in nature and God's plan from a study of the world - began to take over from Pascal's mysticism as the basis of Christian belief.

Isaac Newton, determined to rid religion of irrational mysticism, found certain proof of God's existence in his new physics. As he explained, all the matter in the universe would collapse under gravity if it were not for the fact that the divine creator had placed the celestial bodies throughout infinite space in exactly the right places to prevent it.

Newton's natural theology continues today in the work of writers such as Paul Davies, who assures us that science is a surer path to God than religion. It can also be seen in Stephen Hawking's famous assertion that a grand unified theory will allow us to know the mind of God. Modern cosmology, quantum physics, and the anthropic principle, are all allowing Christian theologians room to resuscitate the God of Reason created by science.

Evolution presents particular problems, but theologians such as Arthur Peacock do not see these as insurmountable. According to Peacock, the fact that God has chosen evolution as the means of creating humanity may tell us that consciousness, rather than the particular physical embodiment represented by humanity, is God's ultimate plan. After all, since self-awareness conveys evolutionary advantage, it is almost certain to arise in one bodily form or another. Natural theologians can therefore continue to believe in a rational God who can be conceptualised and contained by the human mind.

However, the act of reducing God to a concept that can be discussed and analysed, like any other human idea, has its dangers. Such a God can all too easily become a projection of ourselves, embedding in us our own prejudices and making our human ideas absolute. The God of Reason, created by science, has too often been a God of dogma who fills people with fear, rather than wonder and awe.

Richard Dawkins, by attacking religion as a virus of the brain, fails to acknowledge the role of science in creating the particular strain of that virus which is currently afflicting Western Christianity. It is the Western Christian view of God created by science that secular Western society is currently rejecting.

However, religious ideas predate scientific thinking, and are more deeply rooted in the human psyche than science. It is unlikely therefore that the vacuum created by the death of the God of Reason will remain unfilled. The interaction between science and religion will undoubtedly shape the concept of God which will fill the space.

But what form of God will this be? A dialogue between science and religion which recognises the limitations of each could remove the dogma of both Dawkins and fundamentalist believers. It may result in a religion which recognises that belief in God can only be based on personal experience and not on rational belief.

Perhaps we may even see a return of the God of Pascal, a knowledge of whom we are content to accept is forever beyond our grasp. In today's competitive marketplace, Pascal's God may be a lot easier to sell.

Dr Ian Hughes lectures at the department of physics, Queen's University, Belfast