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 20th 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 21st 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 records, and the problem natural selection has in explaining the appearance of complex structures, are brought up over and over again.
The simple fact is there is an enormous knowledge gap: 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:a belief in an omniscient god or gods:
- a belief in miracles;
- a belief that the material human body is separable from a non-material soul;
- a belief that humans have free will, a conscience, and the God-given ability to choose between good and evil;
- a belief in an immortal after-life, sometimes in the form of reincarnation; and
- a belief in the efficacy of prayer, which assumes that direct contact between humans and a deity exists.
There is an enormous knowledge gap 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.
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 fertilisation of an egg by a sperm initiates life, and 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 50 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, a 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 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.