Discussion Group Report

"Scientists, like many others, are touched with awe at the order and complexity of nature. Indeed many scientists are deeply religious. But science and religion occupy two separate realms of human experience. Demanding that they be combined detracts from the glory of each," says Bruce Alberts, the president of the National Academy of Science.

In spite of the compelling evidence for evolution, the teaching of evolution in our schools remains controversial. How can the two views of science and religion about origins be so different?

The publication, Science and Creationism: A View from the National Academy of Sciences, in 30 pages gives a synopsis of the scientific evidence on this question. In the preface Alberts indicates, "The tremendous success of science in explaining natural phenomena and fostering technical innovation arises from its focus on explanations that can be inferred from confirmable data. Scientists seek to relate one natural phenomenon to another and to recognize the causes and effects of phenomena. In this way they have developed explanations for the changing of the seasons, the movements of the sun and stars, the structure of matter, the shaping of mountains and valleys, the changes in the positions of continents over time, the history of life on Earth, and many other natural occurrences. By the same means, scientists have also deciphered which substances in our environment are harmful to humans and which are not, developed cures for diseases, and generated the knowledge needed to produce innumerable labor-saving devices."

He goes on to say, "The concept of biological evolution is one of the most important ideas ever generated by the application of scientific methods to the natural world. The evolution of all the organisms that live on Earth today from ancestors that lived in the past is at the core of genetics, biochemistry, neurobiology, physiology, ecology, and other biological disciplines. It helps to explain the emergence of new infectious diseases, the development of antibiotic resistance in bacteria, the agricultural relationships among wild and domestic plants and animals, the composition of Earths atmosphere, the molecular machinery of the cell, the similarities between human beings and other primates, and countless other features of the the biological and physical world." He quotes Theodosius Dobzhansky (1973), "Nothing in biology makes sense except in the light of evolution."

Alberts continues, "Scientists have considered the hypotheses proposed by creation science and have rejected them because of a lack of evidence. Furthermore the claims of creation science do not refer to natural causes and cannot be subject to meaningful tests, so they do not qualify as scientific hypotheses. In 1987 the U.S. Supreme Court ruled that creationism is religion, not science, and cannot be advocated in public school classrooms. And most major religious groups have concluded that the concept of evolution is not at odds with their descriptions of creation and human origins."

Evolution, Science and Creationism states, helps explain the origin of the universe, the Earth and life. In the late 1920s astronomer Edwin Hubble made observations that he interpreted as showing that distant stars and galaxies are receding from the Earth in every direction. The velocities of recession increase in proportion with distance, a discovery that has been confirmed by numerous and repeated measurements since Hubbel's time. The implication is that the universe is expanding. One hypothesis is that the universe was more condensed at an earlier time. This deduction suggests that all the currently observed matter and energy in the universe were initially condensed in a very small and infinitely hot mass. A huge explosion then sent matter and energy expanding in all directions. This Big Bang hypothesis led to more testable deductions. One was that the temperature in deep space today should be several degrees above absolute zero. Observations have shown this deduction to be correct. The COBE satellite launched in 1991 confirmed that the background radiation field has exactly the spectrum predicted by a Big Bang origin for the universe.

Charles Darwin's original hypothesis on biological evolution has undergone extensive modification and expansion, but the central concepts stand firm. Studies in genetics and molecular biology have explained the occurrence of the hereditary variations that are essential to natural selection. Genetic variations result from changes, or mutations, in the nucleotide sequence of DNA, the molecule that genes are made from. Such changes in DNA now can be detected or described with great precision. In 1799 an engineer named William Smith reported that, in undisrupted layers of rock, fossils occurred in a definite sequential order with more modern-appearing ones closer to the top. Today many thousands of ancient rock deposits have been identified that show a corresponding succession of fossil organisms. Multi-cellular organisms--fungi, plants and animals--have been found in only younger geological strata. The fossil record provides consistent evidence of systematic change through time--of descent through modification. Inferences derived about common descent are reinforced by comparative anatomy. For example, the skeletons of humans, mice and bats are strikingly similar despite their radically different ways of life and diversity of their environments. This suggests a common ancestry for them.

Evolutionary theory explains that biological diversity results from the descendents of local or migrant predecessors becoming adapted to their diverse environments. This explanation can be tested by examining present species and local fossils to see whether they have similar structures, which would indicate how one is derived from the other. Also, there should be evidence that species without an established local ancestry had migrated into the locality. Wherever such tests have been carried out, these conditions have been confirmed.

Embryology is another source of independent evidence for common descent. A wide variety of organisms from fruit flies to worms to mice to humans have very similar sequences of genes that are active early in development. Evidence for evolution also is provided by the discoveries of modern biochemistry and molecular biology. The code used to translate nucleotide sequences into amino acid is essentially the same in all organisms. Moreover, proteins in all organisms are invariably composed of the same set of 20 amino acids. The unity of composition and function is a powerful argument in favor of the common descent of the most diverse organisms. The evidence for evolution from molecular biology is overwhelming and is growing quickly.

Many of the most important advances in paleontology over the past century relate to the evolutionary history of humans. Not one but many connecting links have been found as fossils. They document the time and rate at which primate and human evolution occurred. Scientists have unearthed thousands of fossil specimens representing members of the human family. Most of these specimens have been well dated, often by means of radiometric techniques. They reveal a well-branched tree, parts of which trace a general evolutionary sequence leading from ape-like forms to modern humans.

Science and Creationism closes by saying, "The claim that equity demands balanced treatment of evolutionary theory and special creation in science classrooms reflects a misunderstanding of what science is and how it is conducted. Scientific investigators seek to understand natural phenomena by observation and experimentation. Scientific interpretations of facts and the explanations that account for them therefore must be testable by observation and experimentation.

"Creationism, intelligent design, and other claims of supernatural intervention in the origin of life or of species are not science because they are not testable by the methods of science...publications [of the advocates of these claims] typically do not offer hypotheses subject to change in the light of new data, new interpretations or demonstration of error. This contrasts with science, where any hypothesis or theory always remains subject to the possibility of rejection or modification in the light of new knowledge. The growing role that science plays in modern life requires that science, and not religion, be taught in science classes."