A History of Evolution/Chapter 2
CHAPTER II.
FROM THE CHRISTIAN FATHERS TO KANT.
Inasmuch as almost the entire learning of Europe for several centuries was under the protection and rule of the church, it is important that we examine in some detail the fate of evolution at the hands of that organization.
The early church drew its teachings on the origin and development of life from two sources—the Book of Genesis, and the philosophies of Plato and Aristotle. The early Christian Fathers, or at least the more prominent of them, were very broad-minded in their interpretations of the "revelations" of the Bible. In the fourth century, Gregory of Nyassa began a natural interpretation of Genesis that was completed in that century, and the one following, by Augustine. Despite the plain statements of the direct, or "special" creation of all living things, to be found in Genesis, Augustine promulgated a very different doctrine. He believed that all development took place according to powers incorporated in matter by the Creator. Even the body of man himself fitted into this plan, and was therefore a product of divinely originated, but naturally accomplished development. Thus Augustine, as Moore says, "distinctly rejected Special Creation in favor of a doctrine which, without any violence to language, we may call a theory of Evolution."
It is particularly interesting to note, in these days when prominent men go about denouncing the doctrine of organic evolution as foul, repulsive, and contrary to the will of God, that the early churchmen were not troubled by such narrowness. Augustine not only gave up the orthodox statement of special creation; he modified the conception of time. To him the "days" of Genesis did not mean days of astronomy; they meant long and indeterminable periods of time. And it is particularly interesting to find him rebuking those who, ignorant of the principles underlying nature, seek to explain things according to the letter of the scriptures. "It is very disgraceful and mischievous," says he, "that a Christian speaking of such matters as being according to the Christian Scriptures should be heard by an unbeliever talking such nonsense that the unbeliever, perceiving him to be as wide from the mark as east from west, can hardly restrain himself from laughing."
Augustine was followed by some of the later church authorities, most notably Thomas Aquinas, who lived in the latter part of the thirteenth century. He did not add to the evolution idea, but rather expounded the ideas of Augustine. His importance was due to his high rank as a church authority, not to any ideas which he produced.
During the period between Augustine and Aquinas, however, science almost died out in Europe, and leadership in philosophy went into the hands of the Arabs. Between 813 and 833 the works of Aristotle were translated into Arabic, and they form the basis of the natural philosophies of the Arabians. Avicenna (980–1037) probably held a naturalistic theory of evolution, and is known to have been fundamentally modern in his conceptions of geology. During the tenth century scientific books were imported into Spain in considerable numbers, and the Spanish scientific movement culminated in the works of Avempace and Abubacer (Abn-Badja and Ibn-Tophail). The former held that there were strong relationships between men, animals, plants, and minerals, which made them into a closely united whole. Abubacer, a poet, believed in the spontaneous generation of life, and sketched in a highly imaginative fashion the development of human thought and civilization.
But the reactionary trend of church thought during the dark ages finally attacked and conquered Arabic progress. In 1209 the Church Provincial Council of Paris forbade the study of Arabic writers, and even declared against the reading of Aristotle's "Natural Philosophy." During the middle ages the progress backward was carried to an even greater degree. Men no longer cared to think, or to discover things; they preferred to be told what they should believe. This attitude was encouraged by the authorities of the church, who represented power, and who depended for their easy existence upon the servility of the people at large. Obedience to authority in intellectual as well as in political affairs was demanded of everyone, and by almost everyone was rendered as a matter of course. Those who by chance made real discoveries, and found that they contradicted the established authorities, either refused to believe their Own senses, or else feared to publish their information because of the almost certain prosecution that would follow. To believe blindly, without analysis or question, was considered right and proper; to seek knowledge for oneself was a crime that the medieval church, and her governmental allies, stood ever ready to punish.
But the autocratic enforcement of antiquated dogma, and the serf-like submission to authority, could not go on forever. A revolution came, even within the ranks of the theologians themselves. Giordano Bruno (1548–1600) revived the teachings of Aristotle, and combined them with theories, and combined them with ideas secured by omnivorous reading of Greek, Arabic, and Oriental writings. He undoubtedly had some conception of evolution, compares the intelligence of man and various of the lower animals, and recognizes a physical relationship between them. In geology he was essentially modern, arguing against the six thousand years of Bible chronology, and maintaining that conditions of his day were the same, fundamentally, as those during ancient periods of the earth's history–a doctrine which he probably borrowed from the Arabian, Avicenna.
Before considering others of the philosophers who became, during the sixteenth and seventeenth centuries, the sponsors of the evolution idea, we may well pause to glance at the general state of learning throughout Europe at the beginning of that period. Just as any idea is a product of the men who advocate it, so is its development dependant upon the state of culture in the regions where it is being fostered. We must, therefore, consider the outstanding features of that environment in order to understand the true significance of the progress made along the line in which we are principally interested.
Universities in Europe were founded at the beginning of the twelfth century, following those established by the Arabs[1], Oxford, the most noted university of England, was founded about a century later. For a long time after this, authority still held almost unchallenged sway. Naturalists were mainly compilers, repeating what had been said and done before them, and carefully avoiding anything new. But in the first half of the sixteenth century there sprang up, in the Italian university town of Padua, an important school of anatomy. In 1619 Harvey, an English physiologist, discovered[2] the circulation of blood, and applied the method of experimental study in zoology. This one piece of work was of far more importance than all of his contributions to physiology—of which he is usually considered the real founder—for it gave to scientists the one almost infallible method of securing information. In the latter half of the seventeenth century the study of microscopic organisms was begun, and the foundations of a logical classification of animals was laid by Ray.
It was during these two centuries of progress that the basis of our modern methods of evolutionary investigation was laid. Oddly enough, this was done, not by the naturalists of the time, but by the natural philosophers, such as Bacon and Leibnitz. They found their source of inspiration in the Greek literature, especially the writings of Aristotle, incorporating material offered by the leading naturalists of their times. Probably their biggest contribution was in giving a proper direction to evolutionary research; they saw clearly that the important thing was not what had taken place among animals, but what changes and variations were going on under the very eyes of the investigators. By establishing the fact that evolution was nothing more than individual variations on a stupendously large scale, they brought variation into prominence and laid the foundation for Darwin's final triumph.
The second great achievement of the philosophers was their proof of the principle of natural causation. From Bacon, the earliest, to Kant, one of the last of these workers, this principle was the object of continued study and enthusiasm. Each of them believed that the world, and in fact, the universe was governed by natural causes instead of by the constant interference of a man-like Creator. Of course, this attitude was hailed as the rankest heterodoxy, and was under the ban of the church. Nevertheless, it prevailed, and has stood as a pillar of all natural philosophy of the present day.
Francis Bacon (1561–1626) was the first of the natural philosophers of later-day Europe. He was familiar with the Greek science, but revolted strongly against the authority given it. So radical was his attitude that he went to wholly unjustifiable lengths in attacking the Greeks, calling them "children … prone to talking and incapable of generation." This enmity may partly explain Bacon's failure to put into practice the excellent ideas which he voiced in his epigrams, maxims, and aphorisms. He did, it is true, suggest the means whereby the natural causes of which he wrote might be discovered, but he did little investigation himself. Bacon was too near the reactionarism of the middle ages to consistently practice the inductive method of study, and as a result his work was not of lasting value.
The rebellion of Bacon in England was followed by that of Descartes in France, and Leibnitz in Germany. The latter philosopher did much to revive the teachings of Aristotle, likening the series of animals to a chain, each form representing a link. This conception, while good enough in Aristotle's time, was out of date when revived by Leibnitz, and did much to hamper a true interpretation of the evolutionary sequence. As we shall see more than once in this study, scientific ideas are not like statues or paintings, things of permanent and immutable value. An idea that was good, and valuable, a hundred years ago may be neither today, and its revival would work distinct harm to knowledge. The "faddism" against which enemies of science complain is neither harmful nor iniquitous. An idea should be used to its utmost as long as it represents the height of our knowledge; then, when it has been replaced by new information which is an outgrowth of itself, should be relegated to the museum of scientific antiquities. An ancient, worn-out idea is just as harmful in science as it is in politics; the sooner it is done away with, the better for all concerned.
One of the most important, and at the same time, most puzzling, of the German natural philosophers was Emmanuel Kant (1724–1804). When thirty-one years of age Kant published a book entitled, "The General History of Nature and Theory of the Heavens," in which he attempted to harmonize the mechanical and teleological views of nature. He considered nature as being under the guidance of exclusively natural causes, a very advanced position when compared with the teological conceptions of other Germans. But in his critical work, "The Teological Faculty of Judgment," published in 1790, he abandoned his progressive views on causation, dividing nature into the 'inorganic,' in which natural causes hold good, and the 'organic,' in which the teleological principle prevails. He called to the support of this conception the discoveries of the then new science of paleontology, saying that the student of fossils must of necessity admit the existence of a careful, purposive organization throughout both the plant and animal kingdoms. That this assertion was unfounded is shown by the fact that not a few modern paleontologists are strong defenders of rationalism and the mechanistic conception of all life activities.
But in spite of the fact that Kant was so awed by the immensity of the problem of organic evolution that he declared it impossible of solution, he nevertheless declared himself in favor of the careful study of all evidence bearing upon it. In a most striking passage, quoted by Schultze and Osborn[3], he says:
"It is desirable to examine the great domain of organized beings by means of a methodical comparative anatomy, or order to discover whether we may not find in them something resembling a system, and that too in connection with their mode of generation, so that we may not be compelled to stope short with a mere consideration of forms as they are … and need not despair of gaining a full insight into this department of nature. The agreement of so many kinds of animals in a certain common plan of structure, which seems to be visible not only in their skeletons, but also in the arrangement of the other parts … gives us a ray of hope, though feeble, that here perhaps some results may be obtained by the application of the principle of the mechanism of Nature, without which, in fact, no science can exist. This analogy of forms strengthens the supposition that they have an actual blood relationship, due to derivation from a common parent; a supposition which is arrived at by observation of the graduated approximation of one class of animals to another." He goes on to say that there is an unbroken chain extending from man to the lowest animals, from animals to plants, and from plants to the inorganic matter of which the earth is composed. And yet the man who, in 1790, could give so clear an outline of the basic facts of evolution, was unable to believe that the sequence which he perceived would ever be understood! For in another passage he says:
"It is quite certain that we cannot become sufficiently acquainted with organized creatures and their hidden potentialities by aid of purely mechanical natural principles, much less can we explain them; and this is so certain, that we may boldly assert that it is absurd for man even to conceive such an idea, or to hope that a Newton may one day arise to make even the production of a blade of grass comprehensible, according to natural laws ordained by no intention; such an insight we must absolutely deny to man[4]."
Perhaps the production of a blade of grass is not yet thoroughly comprehensible to us, but certainly the essential steps leading to that production are now well known. Even at the time Kant wrote there lived a man who did much to render the explanation possible, and another who, though disbelieving in evolution of any sort, perfected the means by which evolutionists were to arrange and label the members of the animal and plant kingdoms in order to make the study of them orderly and comprehensible. The great philosopher's passion for accuracy, although an unusual and most creditable character in an age noted for its loose thought and wild speculation, prevented him from seeing the great significance of his own work. When man is able to comprehend a problem, and to state it in clear, accurate language, the solution of that problem is almost assured. The final triumph may be years, or even centuries away, but its eventual coming need hardly be questioned.