It is an interesting fact that in our complex modern world there are but two surviving hy­potheses of origins of man and his associated plants and animals. According tothese hypothe­ses, organisms either have evolved into their pres­ent forms or were created much as we see them today.

The great majority of thinking men are evolu­tionists. To this group belong most churchmen who build their faith upon God's Word. They believe in the existence of a Supreme Being, most certainly. Many of them believe in the inspiration of the Scriptures and that God did create living things. However, it is their opinion that the cre­ative act merely produced simple, single-celled or­ganisms, which later evolved by natural processes into their present complex forms. This opinion is a compromise conclusion based upon two concepts : first, that modern scientists must be correct in their belief that evolution has occurred; and sec­ond, that the Scriptures must be inspired. To these evolutionists who are sometimes called Day-age theorists, the days of creation week were vast stretches of evolutionary time, the close of each day marking the end of an evolutionary period of development. The number of purely mechanistic evolutionists, those who think they see no evidences of a Supreme Intelligence in nature, has decreased in recent years, at least in America.

The comparatively small group of special cre­ationists, as in the case of the evolutionists, is not found entirely within a single denomination. True, all Seventh-day Adventists believe that God cre­ated our organic world in seven literal days and that the original morphological details of these or­ganisms were basically as they are today—simple and complex appearing on our earth at the same time. But equally sincere and forthright special' creationists are found within the ranks of almost every other denomination.

The chief concern of these paragraphs is a con­sideration of the scientific accuracy of these two hypotheses. Much heat has been generated in discussions of evolution versus special creation. The evolutionist believes with all sincerity that the weight of accumulated facts in favor of his theory is now so great that it overcomes all in­telligent opposition by its sheer mass. H. H. Newman, professor of zoology at the University of Chicago, crystallizes the evolutionist's opinion of the theory of special creation (and, incidentally, of creationists) in these words:

"There are no rival hypotheses [of evolution] except the outworn and completely refuted idea of special creation, now retained only by the ignorant, the dogmatic, and the prejudiced." ¹

The special creationist feels with equal sincerity that he does not have an exclusive corner on the traits possessed by the individuals listed by Doctor Newman. Too frequently a discussion of the sci­entific accuracy of the two theories merely degen­erates into the extremely unacademic procedure-of mud slinging. Let us now ignore the mud and get down to the bedrock of facts. Which of these hypotheses is the more scientific, that is, the more in harmony with natural facts?

Any idea which is to pass as a theory must measure up to sorne very exacting specifications. Through classification and comparison of facts there are often brought to light certain broad and general truths which enable us to embody in one statement a great many known facts and to predict a great many other facts. The discovery of these general truths, or natural laws, is an extremely important goal of science. The objective of the scientist thus becomes, in the words of the great astronomer Kepler, the endeavor to "think the thoughts of God after Him."

In the search for these laws scientists make use of certain tentative explanations, or hypotheses, which are the product of the imagination of the scientific worker and are in agreement with many of the facts which are known about the subject under consideration. Many hypotheses are soon shown to be wrong, but a hypothesis which sur­vives the test of newly discovered facts and is not displaced by some more reasonable hypothesis at­tains in time to the dignity of a theory. A theory is not recognized, however, as a natural law until it has long stood the test to which it is constantly being put by the discovery of new facts. In the light of this standard usage among scientific work­ers it is appropriate to question whether either the evolution theory or the theory of special creation has reached the place where it may accurately be termed a theory.

In these paragraphs we are addressing ourselves to a scientific hypothesis of origins. By their own definition scientists assert that in order for any­thing to' be scientific it must include only such facts as can be conveyed to the minds of others by definite and precise statements. It does not in­clude any facts which have not been verified and subjected to the test of experimentation or re­peated accurate observation.

According to scientists, the methods of science are intellectual; that is, they are based upon rea­son and logic, not upon prejudice, sentiment, or emotion. Science is the concern of the head, not of the heart. Knowing in the intellectual sense, may not be the most important thing in life, but it is the only thing with which science is con­cerned. Many of the most important facts of human experience, having to do with emotion, sentiment, and faith; are by no means purely intellectual in their nature, and their worth is not necessarily to be judged by the wholly intellectual stand­ards of science. To insist that their value be judged by such standards is no more justifiable than to permit emotion and sentiment to enter into scientific thinking. I make these statements in order that we may understand the use of the adjective "scientific" and the noun "hypothesis" in our title.

II

In the light of this delimitation of terms, let us first briefly discuss the "theory" of evolution. A search for a definition of evolution may lead the searcher into a serious state of mental confu­sion because of the great diversity of opinion among evolutionists concerning what the asser­tions of their theory are. However, they all agree quite well in the assumption that life appeared on this earth in extremely simple forms and has de­veloped into present-day complex manifestations through the operation of natural laws. Because of its recency and because of its popularity among evolutionists, I will use the definition set forth by Theodosius Dobzhansky, professor of zoology at Columbia University. He says :

"The theory of evolution asserts that (a) the beings now living have descended from different beings which lived in the past; (b) the discontinuOus variation ob­served at our time level—the gaps now existing between clusters of forms—have arisen gradually, so that if we could assemble all the individuals which have ever in­habited the earth, a fairly continuous array of forms would emerge; (c) all these changes have arisen from causes which now continue to be in operation and which therefore can be studied experimentally."

If we state the essence of this definition in a simple way we could say : Evolution asserts that the living kinds of plants and animals have de­scended from less complex kinds through the agency of natural forces now in operation which are subject to laboratory experimentation. Thus the principal assertion of evolution is that the nat­ural forces of our day have caused and are causing new kinds of animals to appear; that is, modern birds and reptiles have developed from more primi­tive ruling reptile forms,³ and man and ape have evolved from the same apelike ancestor.⁴ There­fore, to test the scientific accuracy of the evolution "theory" it becomes necessary to discover whether present-day natural forces are or are not capable of producing new kinds of organisms.

III

For more than twoscore years hundreds of genetical scientists have had under extremely care­ful scrutiny, both in the formal laboratory and in the field, the natural forces which produce vari­ation among organisms. The summarized results of this research in the field of origin of hereditary differences can be found in any of the numerous collections of genetical principles on the book mar­ket today. (For example, see Sinnott and Dunn⁵ and Snyder.⁶ A study of these compendiums shows that geneticists are agreed that all variations in plants and animals may be grouped into two great classes: environmental and autogenous.

Environmental variations, those due to the di­rect action of the environment, may give rise to differences as great as are seen between the gnarled and stunted fir on the mountaintop and one with identical inheritance which has grown into a magnificent giant in the valley. Environ­ment causes the difference in appearance between the potato plant grown in the dark and one grown in the light. It likewise, through nutritional ef­fects, is responsible for the differences between the worker honeybee and the queen. Environmen­tal factors may cause such differences between the members of a pair of human identical twins as tanned or pale, well fed or undernourished, scarred from accident or operation, or differences in emo­tional nature and reaction. However, it is the unanimous opinion of geneticists that the environ­mental class of variations does not furnish the changes which are inherited according to Men­del's principles. Fortunately, the loss of an arm, an environmental change, does not affect the germ line. A man may. lose all his limbs and still be­come the father of perfectly normal children. Therefore, all geneticists are agreed that environ­mental variation cannot in any way accomplish the change of one kind of organism into another kind.

If evolution is taking place now, and such is the opinion of the vast majority of scientists, evolu­tionary geneticists agree that it must be accom­plished by autogenous variation. Variation of this type is due to changes in chromosomes, to changes in the hereditary units (genes) within the chromo­somes, or to both. These autogenous variations are commonly classified by evolutionists into three main categories: (a) recombinations, (b) gene mutations, and (c) chromosome changes.⁷ Upon the kind of changes which these variations produce in organisms hangs the scientific proof or disproof of the "theory" of evolution. In the following three sections it will be necessary to discuss very briefly the nature of the variation which is actually accomplished by each of these three classes of chromosome and (or) gene changes.

IV

Recombinations.—These are the commonest source of differences in appearance between par­ents and offspring and among offspring. How­ever, they are not, properly speaking, new differ­ences at all, but are due to rearrangements of heritable elements which were already in the germ lines. Examples of this type of variation are seen in the appearance of the one blue-eyed child among otherwise brown-eyed progeny of two brown-eyed parents. Another illustration is furnished in the birth of a red-and-white calf to a line of Holstein-Friesian cattle which have been only black and white for seven or eight generations. This type of variation is sometimes called a "throwback." The red color had been in the germ line all the way from those of its Dutch ancestors, which were red and white, on down, but could not express it­self because black was dominant. When two of these recessive reds meet in the same fertilized egg, the result is a: red-and-white calf.

That this type of variation is the source of much of the delightful diversity so characteristic among closely related individuals, is well known, but it is obvious that such changes can never give rise to new kinds of organisms. Even optimistic evolu­tionists make no such claims for it.

References

H. H. Newman, Evolution, Genetics, and Eugenics (The University of Chicago Press, 1930), p. 59.

T. Dobzhansky, Genetics and the Origin of Species (rev. ed.; Columbia University Press, 1941), P. 7.

A. S. Romer, Man and the Vertebrates (3d ed. : The University of Chicago Press. 1941), p. 99.

Id., pp. 186-190.

E. W. Sinnott and L. C. Dunn, Principles of Genet­ics (3d ed.; McGraw-Hill Book Co., 1939).

L. H. Snyder, The Principles of Heredity ( 26 ed., D. C. Heath Co., 5940).

'Sinnott and Dunn, op. cit., p. 293.