HEHN, V. Wanderings of Plants and Animals. 1885. HILL, H. W. The New Public Health. 1916. HILZHEIMER, M. Die Hausthiere in Abstammung u. Entwicke lung. 1909. HOPKINS, A. A. 2. Man the KEEN, W. W. 1914. The Book of Progress: 1. Man the Creator. Destroyer. 3. Man and Nature. 1915. Animal Experimentation and Medical Progress LEPRINCE and ORENSTEIN. Mosquito Control in Panama. 1916. Rubber and Rubber Planting. 1913. LOCK, R. H. MARTIN, E. A. MASON, O. T. The Story of a Piece of Coal. 1903. Progress of the Century, the. Monographs by numerous authors. 1902. RILEY, W. A., and JOHANNSEN, O. A. Handbook of Medical Entymology. 1915. ROGERS, J. E. The Book of Useful Plants. 1913. WILLIAMS, H. S. Miracles of Science. 1914. WILLIS, J. C. Agriculture in the Tropics (2nd Ed.). 1914. CHAPTER IV THE EVOLUTION OF MAN The real test of the scientific work of a man lies in the accuracy of his observations, not in the permanency of his explanations. Assuming that the observer has really seen that which he describes and has not been fooled by his senses, the record stands for all time. His attempt to explain the causes of what he has seen is limited necessarily by the general knowledge of his time. When he goes beyond this he merely guesses, and guesses are likely to be incorrect. Darwin's name will go down through the ages as one of the greatest scientists, yet every explanation and guess he made will probably yield place some day to others based on fuller and more accurate information than existed in his day. Man has two methods of approaching his intellectual problems speculation and research. Each of these has its advantages and dangers. Since there are several possible answers to most questions, speculation may possibly hit on the correct solution; or, as often happens, may stimulate the search for evidence. Research is much more exacting in its requirements and much more likely to throw out of court questions that have no standing. They speculated long in the Middle Ages as to the number of angels that could stand on the point of a needle, but research methods demanded of the student an ability to see angels that was lacking. Any given man is likely to combine these methods and, not infrequently, forget when he leaves the things he has seen and enters upon the dis cussion of the unseen. This habit causes his later readers great inconvenience, for it demands a knowledge of the author's background. To find Karl Marx, for example, in 1848 writing a Communistic Manifesto and objecting to the term socialist is quite disconcerting until the meaning of the term at that time is known. So far as our minds can perceive, there are really very few ways in which life could have started on earth. It was either created by some outer power or else evolved because of the nature of matter. In either case it may have been an event occurring at one time, or a process lasting for ages. It appeared either as a simple or finished product, each variety of organism either related to or entirely distinct from other varieties. We have then in essence two main possibilities. Life was created (whether at one time or repeatedly, whether in the egg or the adult stage); life was evolved (whether at one time or repeatedly), or a combination of the two. That is, life was once created and has since evolved. Even the attempt to trace life on earth to other planets but removes the question one stage. All other suggested answers are but modifications of these. If these facts be kept in mind we shall not be surprised that the ancient Greeks in their attempts to explain the world hit upon theories that are strikingly like some of the results of modern investigation. Some five hundred years before Christ, Thales of Miletus saw that eternal change characterized nature and thought that water was the principal element. His follower, Anaximander, asserted that living beings were developed from lifeless matter. In the mind of Empedocles (495-435 B. C.) these ideas took such definite shape that he has been called "the father of the evolutionary idea." "There are,” said he, "four elements - eternal, indestructible Fire, Air, Earth, Water. These are acted upon by two forces: Love, which unites; Hate, which separates; and there arise by spontaneous generation living organisms; first plants, then animals." Curiously enough, Empedocles asserts that parts of animals precede the whole; heads without bodies, "eyes that strayed up and down in want of a forehead," etc., which combining produced monsters. These died, being unable to reproduce, and gradually more perfect forms replace them. Apparently there is here a vague idea of a struggle for existence and survival of the fittest. The first student of natural history known to us was Aristotle (384-322 B. C.). In his "Physics and Natural History of Animals" we find that he knew some five hundred different species and was keen enough to see that sponges were animals. His study led him to the belief that purpose, law and design lay back of nature. He saw some of the facts of heredity and claimed that children inherited the characters acquired by their parents. He saw the coördination of the parts of the body with the accompanying division of labor. Life appeared to him as a function of the organism. He thought that before the higher animals appeared there were soft masses of sexless germs. Apparently at times Aristotle identified these germs with mythological monsters. By spontaneous generation inorganic dust is changed to plants which have no feeling, later come animals endowed with sensibility. There is an inner perfecting principle which causes an evolution into the higher and more beautiful forms. Matter offers resistance to the forces shaping it, hence struggle is a natural process which results in progress. He rejected the implication of Em pedocles as to the survival of the fittest for he said that Empedocles believed in chance. Said Aristotle: "It rains not from chance, but from necessity." Had not his desire to emphasize the principle of law led him to reject this idea he would have outlined in all essentials the evolutionary theories of Darwin. Yet we must note the crudity and inconsistency of many of his ideas. Eels and flies might still arise from spontaneous generation. "Plants are evidently for the sake of animals and animals for the sake of man: thus Nature, which does nothing in vain, has done all things for the sake of man.' It was not accident that led these students and many others here unmentioned to see that the beginnings of life were probably in water or slime. They dwelt by the sea and were familiar with the fact that it sheltered many of the lower forms of life. They believed that life originated in its lowest forms directly from the earth, that it changed by a process of evolution. With Aristotle we reach the culmination of Greek thought. It is evident that the Greeks combined considerable knowledge of the actual world with very shrewd speculation. They had gained a conception of gradual change from the simple to the complex. Their ideas of cause and law were gradually extended to natural phenomena such as rain, storm, lightning and even to the action of the gods themselves. They were rapidly approaching the idea of a "reign of law." But the Greek nation was tottering, and soon to fall. The Romans were interested in other problems and the only one even to maintain this scientific attitude was Lucretius (50 B. c.) whom Clodd calls the "first anthropologist." The oriental idea of an almighty God who sits on high 1 OSBORN, H. F. From the Greeks to Darwin, p. 52. |