III.

Key Developments During the Renaissance

The situation began to change during the Renaissance, a period of tremendous cultural achievement in Europe that began in the early 14th century and ended about 1600. The scientific revolution can be seen as a major aspect of the sweeping and far-reaching changes of the Renaissance. In broad terms the scientific revolution had four major aspects: the development of the experimental method, the realization that nature obeys mathematical rules, the use of scientific knowledge to achieve practical aims, and the development of scientific institutions.

A.

Development of Experimental Method

The Renaissance was the period when the experimental method, still characteristic of science today, began to be developed and came increasingly to be used for understanding all aspects of the physical world. Previously, the natural world had been thought to be comprehensible based on thoughtful consideration alone. The experimental method holds that understanding comes through hands-on trial and error under controlled conditions. The experimental method was not in itself new—it had been a common aspect of the natural magic tradition from ancient times. For example, all the experimental techniques used by the English physicist William Gilbert, author of what is generally acknowledged to be the earliest example of an experimental study of a natural phenomenon, De Magnete (1600; Of Magnets, Magnetic Bodies, and the Great Magnet of the Earth, 1890), were first developed by Petrus Peregrinus, a renowned medieval magus (magician).

Experimentation was a major aspect of the natural magic tradition and was ready for appropriation by Renaissance natural philosophers who recognized its potential. The experimental methodology used in magic became more acceptable to Renaissance scholars thanks to the rediscovery of ancient magical writings. Religious opposition to magic had less force after the discovery of various writings allegedly written by Hermes Trismegistus, Zoroaster, Orpheus, and other mythical or legendary characters. We now know these texts were written in the early centuries of the Christian Era and deliberately attributed to such legendary authors, but Renaissance scholars believed they were genuinely ancient documents. This gave the texts great authority and led to increased respect for magical approaches.

Increased emphasis on experience and observation complemented the adoption of manipulative experimental techniques. Andreas Vesalius, innovative professor of surgery at the University of Padua, claimed to have noticed over 200 errors in Galen's anatomical writings when he performed his own dissections. Scholars had previously relied on Galen’s works rather than performing their own dissections.

Vesalius's emphasis upon a return to anatomical dissection led to major discoveries. William Harvey, who was taught by one of Vesalius's successors at Padua, discovered that blood circulates through the body. Similarly, the discovery of numerous new species of animals and plants in the New World led to a more empirical approach to natural history. Previously, bestiaries (books containing collected descriptions of animals) and herbals (books containing collected descriptions of plants) had included religious symbolism, legends, superstitions, and other nonnatural lore. Since there was no equivalent information about newly discovered species, however, herbals and bestiaries compiled after the Renaissance were more likely to record properties based on actual observation.

The advent of printing also played an important part in the transmission of accurate information. When the circulation of texts depended upon handwritten copies, illustrations were often crudely executed by the various scribes who copied the book. Subsequent copies of the copy could be unrecognizable. In the preparation of a printed edition, however, a skilled illustrator could be called in to prepare a single illustration that would then be mass-produced. The standard of illustrations improved immeasurably. Almost inevitably the illustrations became more realistic and stimulated a concern for proper observation of natural phenomena.

Another important aspect of the new focus on experimentation and observation (empiricism) was the invention of new observational instruments. The Italian astronomer Galileo, for example, used the telescope—first developed for commercial purposes—to make astonishing astronomical observations. His exciting success stimulated the development of a whole range of instruments for studying nature, such as the microscope, thermometer, and barometer.

B.

Mathematization of Nature

The scientific revolution has also been characterized as the period of the “mathematization of the world picture.” Quantitative information and mathematical analysis of the physical world began to be seen to offer more reliable knowledge than the more qualitative and philosophical analyses that had been typical of traditional natural philosophy. The mathematical sciences had their own long history, but thanks to Aristotle's strictures they had always been kept separate from natural philosophy and regarded as inferior to it. Aristotle's authority weakened throughout the Renaissance, however, as the rediscovery of the writings of other ancient Greek philosophers with views widely divergent from those of Aristotle, such as Plato, Epicurus, and the Stoics, made it plain that he was by no means the only ancient authority.

As skepticism became credible in light of the remarkable exposures of the failings of traditional intellectual positions, mathematics became an increasingly powerful force. Mathematicians claimed to deal with absolute knowledge, capable of undeniable proof and so immune from skeptical criticisms. The full story of the rise in status of mathematics is complex and crowded. Notable contributors included Polish astronomer Nicolaus Copernicus, who claimed that, for no other reason than that the mathematics indicated it, Earth must revolve around the Sun, and German astronomer Johannes Kepler, who reinforced this idea with astronomical measurements vastly more precise than any that had previously been made. Copernicus’s moving Earth demanded a new theory of how moving bodies behave. This theory of motion was effectively initiated as a new mathematical science by Galileo and reached its pinnacle a few decades later in the work of Isaac Newton.

C.

Practical Uses of Scientific Knowledge

Experimentalism and mathematization were both stimulated by an increasing concern that knowledge of nature should be practically useful, bringing distinct benefits to its practitioners, its patrons, or even to people in general. Apart from supporting dubious medical ideas, the only use to which natural philosophy had been put throughout the Middle Ages was for bolstering religion. During the scientific revolution the practical usefulness of knowledge, an assumption previously confined to the magical and the mathematical traditions, was extended to natural philosophy. To a large extent this new emphasis was a result of the demands of new patrons, chiefly wealthy princes, who sought some practical benefit from their financial support for the study of nature. The requirement that knowledge be practically useful was also in keeping, however, with the claims of the Renaissance humanists that the vita activa (active life) was—contrary to the teachings of the Church—morally superior to the vita contemplativa (contemplative life) of the monk because of the benefits an active life could bring to others. The major spokesman for this new focus in natural philosophy was Francis Bacon, one-time Lord Chancellor of England. Bacon promoted his highly influential vision of a reformed empirical knowledge of nature that he believed would result in immense benefits to mankind.

D.

Development of Scientific Institutions

Finally, the scientific revolution was also a period during which new organizations and institutions were established for the study of the natural world. While the universities still tended to maintain the traditional natural philosophy, the new empirical, mathematical, and practical approaches were encouraged in the royal courts of Europe and in meetings of like-minded individuals, such as the informal gatherings of experimental philosophers in Oxford and London that occurred during the 1650s. The Royal Society of London was established on a formal basis in 1660 by attendees of those earlier gatherings. Although nominally under the patronage of Charles II, the Royal Society received no financial support from the monarchy. A similar French society, the Académie des Sciences de Paris, however, was set up by Jean-Baptiste Colbert, Louis XIV's controller-general of finance, and its fellows were paid from the treasury. Whatever their precise constitution, the proliferation of collaborative scientific societies testifies to the widespread recognition that, as Bacon wrote, “knowledge is power,” and knowledge of nature is potentially extremely powerful.