Looked at from two points of view—how mankind acquires knowledge and how life has evolved—there is no room for religion or the existence of a supernatural power in the development of mankind. Religion has simply been the expression of man’s ignorance of, and his blind defence against, the operation of natural forces which he did not yet understand.
Thinking is a function of the brain, just as grasping is a function of the hand and walking a function of the feet; each function acquiring competence by training and experience. In order to think the brain must have something to think about; the material the brain thinks about is drawn from the world around through the medium of the senses—seeing; hearing; tasting; feeling and smelling. The thought material thus acquired, compared and generalised upon, determines the outlook of the individual, and the nature of this thought material is itself limited by the individual’s contact with the world; his own experience and the passed on experience of others through reading and talking. The most important contact a person has with the world is that concerned with the satisfaction of his fundamental needs—food, clothing, shelter and the reproduction of his kind—and, therefore, these are the contacts that dominate his life, bring him into social relations with his kind, and, in general, shape his outlook.
We can only think of things that actually exist, but, we can put pieces of actual existence into fantastic forms. We can, in imagination, take a female form, attach a fish tail to it and produce and imaginary mermaid. We can also, in imagination, put wings on elephants and picture them flying through the air. But we cannot produce anything in imagination that does not already exist in some form in the world. Thus the religious imagine God as some kind of man. The brain has the faculty of working up the material drawn from the environment, just as the digestive apparatus has the faculty of digesting food that comes to it—and both can suffer from indigestion! The brain is that part of the world which pictures and thinks about the rest of the world. There is no mystery, no unknowable, only that which is not yet known but will be in the course of time. However, as things are always evolving there will always be something not yet known.
The study of evolution has shown that all living things have evolved from relatively simple inorganic molecules to complex organisms as the result of small changes over countless ages. Carbon is a basis of life on earth because it can build exceedingly complicated molecules. Scientists have now shown very reasonably that there has been a transition without a break between non-life and life in the chain that runs; hydrogen—elements—chemical compounds—nuclear acids—proteins—viruses—bacteria—higher organisms. From which it appears that there is no boundary between life and non-life in the evolutionary chain. Thus there is no room for religious explorations in the chemical evolution up to modern man. Man, including the brain, is simply a particular undesigned arrangement of chemicals—mainly hydrogen, carbon, nitrogen, oxygen, phosphorous and sulphur.
The nucleic acids in the above chain have a unique property. Once made they can go on indefinitely initiating copies of themselves. They alone of all molecules posses this ability, which made them the foundation of all life on earth and the raw material of its evolution. They are the stuff the genes are made of, and genes are the carriers of hereditary characteristics. In this sense also the chemical variations of past generations weigh heavily on the body and brain of the living.