HYPOTHESES

I HAVE fallen in love. Alas, he is dead, but has left so much behind that I can pursue my passion. The object of my affection is David Hume, the 18th-century Scottish philosopher. It is very odd as, in general, I have little time for philosophers. For example, I hold the conviction that philosophers of science this century have contributed nothing to our understanding of the nature of science. In two recent and enjoyable debates they have defended themselves against this charge in two ways. Firstly that it is neither their aim nor their obligation to help me understand science. Secondly they claim that philosophers of science, particularly Karl Popper, have influenced scientists and that some of them have actually contributed to science. When philosophers do contribute to science they do so as scientists, not as philosophers. And Popper's contribution to philosophy of science is grossly overrated. His ideas concerning the importance of falsification ignore discovery and do not solve the problem of induction. I am much more impressed with the comment of the historian and physicist Gerald Holton that the graveyard of failed scientists is filled with those who gave up their ideas on the first evidence that they were wrong. As the molecular biologist Francis Crick has pointed out, a theory that fits all the facts must be wrong, as some of the facts will be wrong.

Why then my passion for Hume? He writes, of course, with beauty and clarity but his claim on my affections really rests upon his discussion of religion: central to any contemplation of its relation to science. Hume accepts that it is reasonable to see order and design in nature and thus infers that "there must have been project and forethought in the workman" who created it. However, and on this he is insistent, you cannot then infer any characteristic of this "workman". So if one believes in a Creator there is no rational basis for ascribing to this Creator any abilities other that of creating the universe. It is from arguments like this Hume establishes that religion is based upon faith and not reason.

By contrast, science is based on reason. How then can one account for miracles which appear to contradict reason and science? For Hume the issue is clear: "no testimony is sufficient to establish a miracle, unless the testimony be of such a kind that its falsehood would be more miraculous than the fact which it endeavours to establish". The laws of science in relation, for example, to turning water into wine, are very reliable and deny this possibility. Take another example: it is in principle possible that the Queen is an extra-terrestrial but to establish this would require evidence of the same overwhelming kind required for a miracle.

Many scientists, Galileo, Newton and Faraday for instance, have been deeply religious. Even today large numbers of scientists - more physicists than biologists - are religious. It is not difficult to understand why. What was there before the big Bang? We have to accept that there will never be a complete theory of everything. For even the most successful theory will contain elements for which explanation is impossible. However I share with the much missed physicist Richard Feynman the view that he would rather live with uncertainty and acceptance of our ignorance that sustaining ourselves with foundationless and unprovable beliefs.

Unlike science which requires a special mode of thought which is quite unnatural and belies common sense, religion is a very natural mode of thought. While science historically only arose once, in Greece, all societies have some sort of religion. Perhaps religion arose when humans began to consciously make casual connections. Naturally they required an explanation of where the world came from and the pleasures and inexplicable injustices of life. How natural to assume, as Hume says, that the vicissitudes of human life should suggest "many diverse powers influencing human weal and woe". It is because of the quite different nature of religious and scientific thinking that the two can so happily co-exist in the minds of religious scientists.

Religion and science do come into conflict when they deal with the same phenomena. Creationism which is rampant in many southern state of the USA and is promulgated by fundamentalist sects, proposes that the Bible, rather than Darwin's theory of evolution, explains both animal and human origins. Where, they ask, does DNA come from, and is not the fossil record incomplete? They regard Darwinian theory as flawed and belief in it as just another act of faith. Such arguments fail to recognise that we scientists are not frightened to make clear what we do not know, that our ideas are not based on authority and so can change and that recent understanding of genetics and cell biology underpins evolutionary theory. It is like geology where understanding the physics and chemistry of the earth can explain the past.

Science has severe limitations when it comes to the preserve which religion wishes to claim as its own, namely morality and ethics. Science can contribute nothing to either ethics or morality, for it is about understanding how the world works. It can neither prescribe nor judge human behaviour. However it is not necessary to turn to religion in order to have moral values. Indeed, as Hume says, "morality is natural and is what many would have performed were there no God in the universe". And again "in short, all virtue, when men are reconciled to it by ever little practice, is agreeable: all superstition is for ever odious and burthensome".

! Lewis Wolpert, of University College London, is chairman of Copus. His book, 'The Unnatural Nature of Science, is published by Faber.