Overview: Physical Sciences

700-1449

The year 700 was a turning point in history because it marked the beginning of the medieval era. In the west, small European kingdoms began to unite into larger ones. In the Middle East Islam asserted itself politically and soon became a dominant cultural force. In both Christendom and the Dar-al-Islam the knowledge of ancient civilizations provided a foundation for the long period of growth toward modern western civilization, yet the continuity of learning in these two spheres was quite different.

In marked contrast, Far Eastern civilization was based on centuries of uninterrupted learning. Chinese physical science had begun as early as 2000 b.c., with observational astronomy and a 12-month calendar. Chinese optics was as ancient as that of the Greeks. Alchemy, too, had its roots in Asia in the second century a.d.

Things were also different in the West, where barbarian invasions and the collapse of Roman civilization led to the Dark Ages and the loss of ancient scientific knowledge. In the Middle East Islamic culture became benefited from a tradition that encouraged the pursuit of knowledge and the assimilation of knowledge from earlier cultures.

Medieval Islamic Physical Science

The legacy of ancient knowledge, held in trust by eastern Christian and Persian scholars and augmented by Indian scholars, was the focus of a concerted Islamic effort, beginning in the eighth century, to translate the great corpus of Greek philosophy, science, and mathematics into Arabic. Aristotle (384-322 b.c.), Pythagoras (c. 580-500 b.c.), Plato (c. 428-c. 348 b.c.), Claudius Ptolemy (c. 85-c. 165), and others were diligently studied, demonstrating the importance of knowledge, science, and philosophy in the Islamic world. This effort reached a high point in the early ninth century under the Abbasid caliph al-Mamun.

Arabic astronomers incorporated Indian, Persian, and Near Eastern ideas, along with the central synthesis of Greek thought on the cosmic realm. Among the important contributions they made to the sciences were the first large-instrument observatory (Maraghah in Persia) and the development of accurate astronomical instruments, including the astrolabe, which they used to catalog old stars and discover new ones.

In physics, Islamic scientists learned how to measure an object's specific weight (or weight density) and to use the balance. They also tried to correct Aristotle's theory of projectile motion, which led them to consider ideas on impetus and momentum. Their most important contribution may have been innovative experimental techniques in the study of optics, pioneered by ibn al-Haytham, also known as Alhazen (965-1038).

In the Islamic world, the alchemy of Alexandrian Greece and China were studied, producing the famous Islamic alchemist Abu Musa Jabir ibn Hayyan (c. 721-815). In the next century experimentation helped refine the acid-base theory in the science of chemistry, and Muhammad ibn Zakariyya ar-Razi, also known as Rhazes (c. 865-c. 930), an alchemist who was also the greatest physician in the Islamic world, divided all matter into organic and inorganic categories. Interestingly, the term "alchemy," whose name is derived from the Arabic al-kimiya, was little known in the West until Arabic works were translated in the eleventh century.

Applied physical science was given full attention as well. Islamic thinkers studied geography, minerals, and geology. Ibn Sina, also known as Avicenna (980-1037), produced the first descriptions of Malayan minerals. The close contemporary and equally polymathic Abu Rayhan al-Biruni (973-1048) wrote extensively on physical geology, geography, the problem of determining the circumference of the earth, and his study of India, which resulted in the first correct description of the sedimentary nature of the Ganges basin.

Medieval European Physical Science

Early European scientific thought was hindered by Christian doctrinal distrust of surviving Greek science, which centered on astrology and the physical traditions from Aristotle, neither of which agreed with Scripture. St. Augustine was the first to retreat from this stance by stating that, when dealing with the physical world, experiment should count more than faith-based interpretation.

About the early tenth century, the first Arabic translations and commentaries appeared in Europe, translated into Latin by a dedicated generation of scholars: Domengo Gondisalvi (c. 1134), John of Luna (c. 1134), and others. By the twelfth century these Islamic contributions, along with original Islamic works (such as Ibn Haytham's Book of Optics), fueled much interest in Western science. Unfortunately, these Islamic hand-me-downs were often paraphrases and summaries of Greek thought rather than works in their entirety. Producing complete Latin translations of original Greek texts became the goal of another generation of translators, particularly Gerard of Cremona (c. 1114-1187) and his group at Toledo, followed by Michael Scot (c. 1230), and later William of Moerbeke (c. 1255-1278). Their efforts spurred critical appraisal of past scientific thought, and encouraged independent contributions to physical science.

In the West, little was known about Aristotle, although his works greatly influenced Islamic science, until about 1115, when Arabic paraphrases, commentaries, and partial translations made some of his works available. By the late twelfth and early thirteenth centuries Aristotle's scientific thought had gained much attention in England and France—and ecclesiastical resistance to them only increased curiosity and study. By the 1240s Aristotle had become the foundation of the formal scholastic framework used in the analysis of science and other ideas. Following a concerted effort, all of Aristotle's works had been translated from Greek into Latin by about 1278.

The Aristotelian foundation was built upon by Robert Grosseteste (c. 1168-1253) (who influenced the English Oxford Franciscans), Albertus Magnus (c. 1193-1280), and scholars at the universities of Paris and Toulouse. Soon, however, a more critical appraisal of Aristotle and his ideas surfaced. By the late thirteenth century a formalized school of logic called nominalism emerged. It first appeared in commentaries by John Duns Scotus (c. 1270-1308) and is best known from the work of William of Ockham (c. 1285-1349).

Aristotle's astronomical theory centered on a "Prime Mover" of the universe, which for many medieval European thinkers represented God. This was particularly true for Thomas Aquinas (1225-1274), who used the concept of a Prime Mover in the first of his logical proofs of God's existence. Ockham, on the other hand, by applying strictly nominalist principles, denied that the Prime Mover concept proved the existence of God.

Other Scientific Achievements

The era's heightened interest in science produced further seminal observations and conclusions. In 1269 Peter Peregrinus of Maricourt (fl. 1200s) provided the first experimental study on the magnetization of iron and magnetic poles. Mathematician Jordanus de Nemore (c. 1255) advanced static physics by defining the law of straight-lever equilibrium.

Studies on the reflection and refraction of light, especially rainbow optics, marked the work of Oxford's Grosseteste and the Oxford Franciscans, followed by those of the Pole Witelo (c. 1230-c. 1275), and culminated with Theodoric of Freiberg's (c. 1250-1311) comprehensive rainbow theory. The Oxford and Paris nominalists, particularly Thomas Bradwardine (c. 1290-1349), Jean Buridan (c. 1270-c.1358), and Nicole Oresme (c. 1320-1382), established concepts in the physics of motion, or dynamics.

The scholars at Oxford and Paris also delved into more speculative areas of physical science, such as the possibility of the vacuum (which was judged reasonable though nature seemed to abhor it). Another was the motion of the earth. Though Aristotle's physics and Earth sciencesshaped medieval thought, his astronomy had been supplanted by Ptolemy's (fl. 139-161), despite criticism of its confusing epicenters and epicycles to explain the apparent retrograde movements of the planets. In either case, the earth was considered to be at rest, yet other incessant motions were proposed relating to changing center of gravity by Albert of Saxony (c. 1316-1390), Buridan's student at Paris. This opened the way for conjecture possibility by Oresme (1377) that the earth could rotate, and that its territory obeyed a gravity attraction to the earth's center.

Conclusion

Science during this period was undeniably in its infancy and hampered by its ties to ideological, rather than objective, standards. Despite this, the rediscovery of ancient writings and the exposure of European civilization to Eastern, particularly Islamic, achievements, set the stage for the flowering of scientific knowledge that would occur in the Renaissance.

WILLIAM J. MCPEAK