BEGINNINGS OF MODERN NATURAL SCIENCE
[Sidenote: Two-fold Development of Culture, Science and Art]
Human civilization, or culture, always depends upon progress in two directions—the reason, and the feelings or emotions. Art is the expression of the latter, and science of the former. Every great period in the world's history, therefore, is marked by a high appreciation of aesthetics and an advance in knowledge. To this general rule, the sixteenth century was no exception, for it was distinguished not only by a wonderful development of architecture, sculpture, painting, engraving, music, and literature,—whether Roman, Greek, or vernacular,—but it is the most obvious starting point of our modern ideas of natural and experimental science.
Nowadays, we believe that science is at once the legitimate means and the proper goal of the progress of the race, and we fill our school curricula with scientific studies. But this spirit is essentially modern: it owes its chief stimulus to important achievements in the sixteenth century and the first half of the seventeenth.
[Sidenote: Characteristics of the Sixteenth Century]
Five elements contributed to impress the period that we are now reviewing with a scientific character. In the first place, the humanists encouraged a critical spirit in comparing and contrasting ancient manuscripts and in investigating the history of the distant past; and their discovery and application of pagan writings served to bring clearly and abruptly before the educated people of the sixteenth century all that the Greeks and Romans had done in astronomy, physics, mathematics, and medicine, as well as in philosophy, art, and literature. Secondly, the invention of printing itself was a scientific feat, and its extended use enabled scientists, no less than artists, immediately to acquaint the whole civilized world with their ideas and demonstrations.
Thirdly, the marvelous maritime discoveries of new routes to India and of a new world, which revolutionized European commerce, added much to geographical knowledge and led to the construction of scientific maps of the earth's surface. Fourthly, the painstaking study of a small group of scholars afforded us our first glimpse of the real character of the vast universe about our own globe—the scientific basis of modern astronomy. Lastly, two profound thinkers, early in the seventeenth century,—Francis Bacon and Descartes,—pointed out new ways of using the reason—the method of modern science.
In an earlier chapter, an account has been given of the maritime discoveries of the sixteenth century and their immediate results in broadening intellectual interests. In this chapter, some attention already has been devoted to the rise of humanism and likewise to the invention of printing. It remains, therefore, to say a few words about the changes in astronomy and in scientific method that characterized the beginning of modern times.
[Side Note: Astronomy]
In the year 1500 the average European knew something about the universe of sun, moon, planets, and stars, but it was scarcely more than the ancient Greeks had known, and its chief use was to foretell the future. This practical aspect of astronomy was a curious ancient misconception, which now passes under the name of astrology. It was popularly believed prior to the sixteenth century that every heavenly body exerted a direct and arbitrary influence upon human character and events, [Footnote: Disease was attributed to planetary influence. This connection between medicine and astrology survives in the sign of Jupiter 4, which still heads medicinal prescriptions.] and that by casting "horoscopes," showing just how the stars appeared at the birth of any person, the subsequent career of such an one might be foreseen. Many silly notions and superstitions grew up about astrology, yet the practice persisted. Charles V and Francis I, great rivals in war, vied with each other in securing the services of most eminent astrologers, and Catherine de' Medici never tired of reading horoscopes.
[Sidenote: "The Ptolemaic System">[
Throughout the middle ages the foremost scholars had continued to cherish the astronomical knowledge of the Greeks, which had been conveniently collected and systematized by a celebrated mathematician and scholar living in Egypt in the second century of the Christian era —Ptolemy by name. Among other theories and ideas, Ptolemy taught that the earth is the center of the universe, that revolving about it are the moon, Mercury, Venus, the sun, the other planets, and the fixed stars, and that the entire machine is turned with incredible velocity completely around every twenty-four hours. This so-called Ptolemaic system of astronomy fitted in very nicely with the language of the Bible and with the popular prejudice that the earth remains stationary while the heavenly bodies daily rise and set. It was natural that for many centuries the Christians should accept the views of Ptolemy as almost divinely inspired.
[Sidenote: "The Copernican System">[
However, a contradictory theory of the solar system was propounded and upheld in the sixteenth century, quite supplanting the Ptolemaic theory in the course of the seventeenth. The new system is called Copernican after its first modern exponent—and its general acceptance went far to annihilate astrology and to place astronomy upon a rational basis.
Copernicus [the Latin form of his real name, Koppernigk (1473-1543)] was a native of Poland, who divided his time between official work for the Catholic Church and private researches in astronomy. It was during a ten-year sojourn in Italy (1496-1505), studying canon law and medicine, and familiarizing himself, through humanistic teachers, with ancient Greek astronomers, that Copernicus was led seriously to question the Ptolemaic system and to cast about in search of a truthful substitute. Thenceforth for many years he studied and reflected, but it was not until the year of his death (1543) that his results were published to the world. His book—On the Revolutions of the Celestial Bodies, dedicated to Pope Paul III—offered the theory that the earth is not the center of the universe but simply one of a number of planets which revolve about the sun. The earth seemed much less important in the Copernican universe than in the Ptolemaic.
The Copernican thesis was supported and developed by two distinguished astronomers at the beginning of the next century—Kepler (1571-1630) and Galileo (1564-1642), one a German, the other an Italian. Kepler taught astronomy for a number of years at Gratz and subsequently made his home in Prague, where he acquired a remarkable collection of instruments [Footnote: From Tycho Brahe, whose assistant he was in 1600-1601.] that enabled him to conduct numerous interesting experiments. While he entertained many fantastic and mystical theories of the "harmony of the spheres" and was not above casting horoscopes for the emperor and for Wallenstein, that soldier of fortune, [Footnote: See below, pp. 223, 226.] he nevertheless established several of the fundamental laws of modern astronomy, such as those governing the form and magnitude of the planetary orbits. It was Kepler who made clear that the planets revolve about the sun in elliptical rather than in strictly circular paths.
Galileo popularized the Copernican theory. [Footnote: Another "popularizer" was Giordano Bruno (c. 1548-1600).] His charming lectures in the university of Padua, where he taught from 1592 to 1610, were so largely attended that a hall seating 2000 had to be provided. In 1609 he perfected a telescope, which, although hardly more powerful than a present-day opera glass, showed unmistakably that the sun was turning on its axis, that Jupiter was attended by revolving moons, and that the essential truth of the Copernican system was established. Unfortunately for Galileo, his enthusiastic desire to convert the pope immediately to his own ideas got him into trouble with the Roman Curia and brought upon him a prohibition from further writing. Galileo submitted like a loyal Catholic to the papal decree, but had he lived another hundred years, he would have rejoiced that almost all men of learning—popes included—had come to accept his own conclusions. Thus modern astronomy was suggested by Copernicus, developed by Kepler, and popularized by Galileo.
The acquisition of sound knowledge in astronomy and likewise in every other science rests primarily upon the observation of natural facts or phenomena and then upon deducing rational conclusions from such observation. Yet this seemingly simple rule had not been continuously and effectively applied in any period of history prior to the sixteenth century. The scientific method of most of the medieval as well as of the ancient scholars was essentially that of Aristotle. [Footnote: Exception to this sweeping generalization must be made in favor of several medieval scientists and philosophers, including—Roger Bacon, a Franciscan friar of the thirteenth century.] This so-called deductive method of Aristotle assumed as a starting-point some general of principle as a premise or hypothesis and thence proceeded, by logical reasoning, to deduce concrete applications or consequences. It had been extremely valuable in stimulating the logical faculties and in showing men how to draw accurate conclusions, but it had shown a woeful inability to devise new general principles. It evolved an elaborate theology and a remarkable philosophy, but natural experimental science progressed relatively little until the deductive method of Aristotle was supplemented by the inductive method of Francis Bacon.
[Sidenote: Modern Method of Science: Introduction. Francis Bacon]
Aristotle was partially discredited by radical humanists, who made fun of the medieval scholars who had taken him most seriously, and by the Protestant reformers, who assailed the Catholic theology which had been carefully constructed by Aristotelian deduction. But it was reserved for Francis Bacon, known as Lord Bacon (1561-1626), to point out all the shortcomings of the ancient method and to propose a practicable supplement. A famous lawyer, lord chancellor of England under James I, a born scientist, a brilliant essayist, he wrote several philosophical works of first-rate importance, of which the Advancement of Learning (1604) and the Novum Organum (1620) are the most famous. It is in these works that he summed up the faults which the widening of knowledge in his own day was disclosing in ancient and medieval thought and set forth the necessity of slow laborious observation of facts as antecedent to the assumption of any general principle.
[Sidenote: Descartes]
What of scientific method occurred to Lord Bacon appealed even more to the intellectual genius of the Frenchman Descartes (1596-1660). A curious combination of sincere practicing Catholic and of original daring rationalist was this man, traveling all about Europe, serving as a soldier in the Netherlands, in Bavaria, in Hungary, living in Holland, dying in Sweden, with a mind as restless as his body. Now interested in mathematics, now in philosophy, presently absorbed in physics or in the proof of man's existence, throughout his whole career he held fast to the faith that science depends not upon the authority of books but upon the observation of facts. "Here are my books," he told a visitor, as he pointed to a basket of rabbits that he was about to dissect. The Discourse on Method (1637) and the Principles of Philosophy (1644), taken in conjunction with Bacon's work, ushered in a new scientific era, to some later phases of which we shall have occasion to refer in subsequent chapters.