The publication of Darwin's Origin of Species was followed by bitter controversy between those who believed in the divine creation of species, and those who were persuaded by the logic and power of Darwin's arguments. This controversy seemed to die down in the twentieth century, and it was then common to assert that science dealt with the material world and religion with the spiritual. It was also implicit in this view that science and religion were in some way complementary to each other. Although most of those who were religious accepted the ancient origin of life on this planet and organic evolution, many believed that this evolution was all part of God's plan, presumably for the final appearance of Homo sapiens. At the same time genetics, and in particular population genetics, were explaining how Darwinian evolution could occur, and there were many contemporary examples of natural selection in action. It became clear that mutation and natural selection could explain complex adaptations. This has now been reinforced by DNA sequencing. which is a very powerful tool for illuminating the origins and diversity of species. Now, at the beginning of the twenty first century, there has been a resurgence of creationism, either in the guise of "science creationism" or "intelligent design". The old arguments about gaps in the fossil record, and the problem natural selection has in explaining the appearance of complex structures, are brought up over and over again. The simple fact is that there is an enormous knowledge gap between between evolutionary biologists who are familiar with the wealth of evidence in favour of Darwinian natural selection, and those who are unfamiliar with this evidence, and indeed most often do not even feel there is a need to examine it, because they have blind faith in a divine creator. This is one of the divisions between religion and science, but by no means the only one.
 

Most religions seem to have the following characteristics. First, a belief in an omniscient God or Gods. Second, a belief in miracles. Third, a belief that the material human body is separable from a non-material soul. Fourth, the belief that humans have free will, a conscience, and the God-given ability to choose between good and evil. Fifth, a belief in an immortal after-life, sometimes in the form of reincarnation. Finally, a belief in the efficacy of prayer, which assumes that direct contact between

 humans and a deity exists.

The belief in a non-material soul or spirit, implies that it arises at some stage in human development, and this can be linked to the view that life itself is a mystery, and by implication, outside the realm and understanding of science. Commonly it is thought that the fertilization of an egg by a sperm initiates life, and that the embryo is therefore already a human being. Modern molecular biology has effectively solved the so-called "mystery of life." The genetic material, DNA, is a polymeric chemical, with enormous coding capacity. It directs the synthesis of RNA which in turn is translated into proteins, consisting of one or more polypeptide chains (linear arrays of amino acids). Many proteins are enzymes, and thousands of these have been characterised. The major components of metabolism are well understood. In short, living cells consist of complex chemicals, and their even more complex interactions. There is absolutely no place for a "vital force" or any non-material entity either in the egg, the sperm, the fertilised egg, the embryo, the child or the adult. Thus, there is no non-material soul, nor an afterlife. Again, the vast amount of biological information that has been gathered in the last fifty years cannot be communicated to those who continue to believe in a soul and an afterlife.

The next fundamental difference between science and religion is the issue of free will. In fact, most individuals believe in free will because it is a matter of common experience that they feel free to make their own decisions. For the religious, free will is God's gift to man. However, once it is accepted that we are complex organisms composed only of molecules, the completely new light is thrown on the supposed existence of free will. In making a simple choice, for example, between moving one's right or left arm, we feel completely free, but the fact remains that a signal is transmitted to the muscles that comes from the brain. The brain is not capable of spontaneously creating energy, because if it did it would contravene the law of conservation of energy, so the signal must come from somewhere else. Because we are conscious of feeling free, the signal must come from another part of the brain which is part of our unconscious brain function. Thus, there are forces at work of which we are not aware. These forces are determinants of our behaviour, and free will is no more than an illusion. Of course, some decision making is complex and may depend on knowledge, experience and external factors of which we are well aware, but this does not affect the basic conclusion that we do not have free will.
 

Decades ago C.P. Snow wrote about "The two cultures" drawn from his own experience as a scientist in the 1930s and his later career as a novelist and writer. Discussion about the two cultures has gone out of fashion, but there is no disputing the fact that the divide between modern science, and particularly modern biology, and the general public remains immense. Today's molecular and cellular biology is of enormous sophistication and complexity, and well beyond the comprehension of an intelligent layman. A glance at a modern scientific journal shows that even the titles of research papers (which normally document a further advance in knowledge) are for the most part completely incomprehensible to anyone not actually working in the field. The concept of two cultures is very much alive, in spite of the best efforts of contemporary science writers to explain new advances to the public. This cannot be better illustrated than by the current discussions of organic evolution. On the one hand there is a mass of information documenting the reality of Darwinian natural selection acting on mutations, that are most commonly single changes in DNA sequence. On the other hand there are those who are totally ignorant of this evidence, and who can simply assert that there are "gaps" in evolution (most commonly gaps in the fossil record), and that biological structures are too complex to be explained by mutation and natural selection. The argument can be turned on its head, and I have argued elsewhere that a creator could easily include wheels or propellers in animal design. Yet no wheels or propellers exist in the animal kingdom. The Darwinian explanation for this is perfect: it is impossible to evolve a wheel by stages, because only a whole wheel has function.

There is a huge difference between those who may believe in an omniscient deity who was responsible for the initial creation of the universe, and those who also believe that this deity is in direct contact with human beings, and may influence their behaviour or respond to their prayers. Atheists believe that there is no God who has any contact, influence or interaction with man, whatever the true origin of the universe may be. For religion they substitute humanism, and a belief that the problems of mankind can only be solved by the inhabitants of this planet

It is said to be politically correct to be tolerant of all religions, but why should we be tolerant of the sets of untruths on which all religions are based? It is therefore not good enough for scientists to accept this political correctness. They should believe in the reality of what science has demonstrated over several centuries. To act or believe otherwise is not intellectually rigorous, and is indeed a betrayal of the achievements of their own discipline . Experimental science has established itself as rational and reproducible, and there is no place for the contravention of natural laws, such as miracles, superstition and the occult. Finally, it is often pointed out that religious scientists exist. It seems that these are individuals who can in some way compartmentalise contradictory viewpoints, but this is an ability that I for one find extremely hard to understand.
 

*Robin Holliday obtained his Ph.D. at the University of Cambridge, England. He joined the scientific staff of the John Innes Institute, Bayfordbury, Hertford, in 1958, and there developed molecular models of genetic recombination. In experimental work he studied recombination and repair in the fungus Ustilago maydis and was the first to isolate and characterise mutants defective in these processes in any eukaryotic organism. He later moved to the National Institute for Medical Research at Mill Hill, London, and became head of the new Division of Genetics in 1970. He was elected Fellow of the Royal Society of London in 1976. He and his colleagues also studied possible mechanisms of the senescence of diploid human cells in culture, and their immortalisation. In 1975 he suggested with his student John Pugh that DNA methylation could be an important mechanism for the control of gene expression in higher organisms, and this has now become documented as a basic epigenetic mechanism in normal and also cancer cells. In 1988 he moved to a CSIRO laboratory in Sydney, Australia, where he continued to study ageing, and his book Understanding Ageing was published in l995. The main focus of his experimental work was the epigenetic control of gene expression by DNA methylation in CHO cells. These experiments provide direct evidence that DNA methylation is a primary cause of gene silencing in mammalian cells.