For many years it has been well established scientifically that all known forms of life, including human beings, have developed by a lengthy process of evolution. It is also verifiable today that very primitive forms of life, ancestral to all living forms, came into being thousands of millions of years ago. Humans and the other highly organized types of today constitute the present twig-end of that tree. The human twig and that of the apes sprang from the same apelike progenitor branch. Some possibility of human error, even if very slight, always exists.
Scientists welcome the challenge of further testing of any view whatever.
They use such terms as firmly established only for conclusions founded on rigorous evidence that have continued to withstand searching criticism. The principle of biological evolution, as just stated, meets these criteria exceptionally well. It rests upon a multitude of discoveries of very different kinds that concur and complement one another. It is therefore accepted into humanity's general body of knowledge by scientists and other reasonable persons who have familiarized themselves with the evidence. In recent years, the evidence for the principle of evolution has continued to accumulate.