THE SECOND BIRTH OF SCIENCE

IT IS SOMETIMES SAID, by those with an axe to grind against religion, that the rise of Christianity brought an end to the first great age of scientific progress. This claim is untenable. It is true that one can find statements in the writings of the church fathers that deprecate the study of nature, and that science was not high on the early Christians’ list of concerns. However, one finds the same range of attitudes toward science among the early Christians as among their pagan contemporaries. And the fact is that the glory days of ancient science were long gone by the time Christians became a significant demographic or intellectual force. The golden age of Greek mathematics ended two hundred years before the birth of Christ. (For example, the great Greek mathematicians Archimedes, Eratosthenes, and Apollonius of Perga died, respectively, in 212 B.C., 194 B.C., and 190 B.C..) Only a few great figures in ancient Greek science date from the period after Christ, notably the astronomer Ptolemy, who died around A.D. 165, and the mathematician Diophantus, who died around A.D. 284. At that point, Christianity was still a small and persecuted sect.

As is well known, an impressive revival of mathematics and science began in the Islamic world in the ninth century. Under the Abbasid caliphate, which stretched from North Africa to Central Asia, scholars were able to draw upon the patrimony of the Babylonians and Indians as well as the Greeks. The Muslim contributions to science are memorialized in the many scientific terms of Arabic origin, such as alcohol and alkali in chemistry (a field of inquiry once called “alchemy”); algebra, algorithm, and zero in mathematics; and almanac, azimuth, zenith, and the names of the bright stars Algol, Aldebaran, Betelgeuse, Rigel, and Vega in astronomy. However, the brilliance of Muslim science began to fade after a few centuries. The Islamic theological establishment tended to be indifferent or hostile to speculative Greek thought, and therefore science did not achieve the kind of institutional status in the Muslim world that it later achieved in the universities of Europe.

The second birth of science really came in the Latin West. In the eleventh century, when Western Europe began to recover from the economic and cultural collapse caused by the barbarian invasions, its scholars became aware again, largely through contact with the Arab world, of the ancient Greeks’ great achievements in science. This awareness engendered an insatiable curiosity about and demand for the works of ancient Greek scholars, which led in turn to a frenzy of translations of these works into Latin, either from Arabic sources obtained in Spain or directly from Greek versions obtained from the Byzantines. Universities were invented in medieval Europe, and they were founded in part as places where this newly recovered knowledge could be studied. The intense interest in Greek science—or, as it was called at that time, “natural philosophy”—was shared by clergy and laity alike. Indeed, in medieval universities the study of natural philosophy was a prerequisite for the study of theology. (This would be somewhat analogous to physics being a required course in today’s seminaries.)

For a long time, it was standard for modern scholars to dismiss medieval science as lacking in creativity or true scientific spirit, and as being quite irrelevant to later scientific progress. However, scholars such as Pierre Duhem and A. C. Crombie successfully challenged that consensus. They demonstrated that medieval science was far more vital than had been supposed, and that the picture of monkish scholars slavishly following Aristotle had been overdrawn. The “natural philosophers” of the Middle Ages were quite aware of some of the inadequacies in Aristotle’s ideas and adopted a cautiously critical approach to him, though their interesting critiques were not based on experiments but on logical reasoning—and to some extent on what we would today call “thought experiments.” In addition, the medievals took tentative steps toward developing a science of motion. The crucial concept of uniform acceleration (or in their quaint terminology, “uniformly difform” motion) became understood for the first time; the notion of “impetus” (an anticipation of the concept of “momentum”) was developed; graphs were invented to facilitate reasoning about mathematical functions and motion; and mathematical laws of motion were first proposed. Some historians, such as Duhem, Crombie, and more recently Stanley Jaki, have even claimed that these ideas directly influenced the thinking of Galileo and other founders of the Scientific Revolution (though the extent of this influence is disputed, and the issue is far from settled).

Be that as it may, there is one way in which the revival of science in medieval Europe certainly did lay the groundwork for the Scientific Revolution to come. It “institutionalized” science, as Edward Grant, the noted historian of science, has put it. In the ancient and Arab worlds, science like art had depended upon the patronage of wealthy or powerful individuals who happened to have a personal interest in it. It was therefore a hit-or-miss affair, subject to the vicissitudes of politics and economic fortunes. By contrast, in the medieval universities there was created for the first time a stable community of scholars that studied scientific questions continuously from generation to generation. That is, a scientific community came into being. By the end of the Middle Ages there were nearly one hundred universities in Europe, and their graduates numbered in the tens of thousands. This created a significant literate public that was interested in science, was willing to pay to be taught or obtain books about it, and from whose ranks scientific talent could emerge.

Without the scientific community and the scientific public created by the medieval universities, the Scientific Revolution would not have had fertile soil in which to germinate.