II.

Understanding of the Physical World in the Middle Ages

Throughout the Middle Ages, formal attempts to understand the physical world were developed, chiefly in the arts and medical faculties of the medieval universities. This natural philosophy, as it was known, derived almost entirely from the teachings of the ancient Greek philosopher Aristotle. Most of the brilliant legacy of ancient Greek thought had been lost to Western Europe after the fall of the Roman Empire in the 5th century. When this legacy began to be recovered from Byzantine and Islamic sources where it had to some extent been preserved, it was the works of Aristotle that had the most immediate impact and began to dominate Western philosophical thought (see Western Philosophy). The learning in the two most powerful faculties of the medieval university system, the faculties of divinity and of law, was based on ancient writings: the Bible and Roman Law, as codified by Byzantine emperor Justinian I in the Corpus Juris Civilis (534; Body of Civil Law). The arts and medical faculties tended to follow suit, with the result that study focused not on the natural world itself, nor on the techniques of practical healing, but instead on the writings of Aristotle and Galen, who was the equivalent medical authority in ancient times. Concentration on the study of texts meant that there was little or no practical study or experimentation within the university curricula.

This tendency to avoid practical subjects was reinforced by Aristotle's own teachings on how natural philosophy should be conducted and on the correct way of determining the truth of things. He rejected the use of mathematics in natural philosophy, for example, because he insisted that natural philosophy should explain phenomena in terms of physical causes. Mathematics, being entirely abstract, could not contribute to this kind of physical explanation. Even those branches of the mathematical sciences that seemed to come close to explaining the physical world, such as astronomy and optics, were disparaged as “mixed sciences” that tried to combine the principles of one science, geometry, with those of another, physics, in order to explain the behavior of heavenly bodies or rays of light. But the results, according to Aristotle, could not properly explain anything.

Although geometry and arithmetic were taught in the university system they were always regarded as inferior to natural philosophy and could not be used, therefore, to promote more practical approaches to the understanding of nature. Within the universities, even the study of plants and animals tended to be text-based. Students learned their knowledge of flora, for example, from the compilations of herbal and medicinal plants by the Greek physician Pedanius Dioscorides, leaving more localized and practical knowledge to lay experts in herbal lore outside the university system. Similarly, alchemy and other empirical (based on experimentation and observation) aspects of the natural magic tradition were pursued almost entirely outside the university system.

This fragmentation of studies concerned with the workings of nature was reinforced throughout the Middle Ages by the Roman Catholic Church. After some initial problems with non-Christian aspects of Aristotelian teaching, the Church embraced such teaching as a handmaiden to the so-called “queen of the sciences,” theology. The Church considered Aristotelian natural philosophy to provide support to religious doctrines, but other naturalist pursuits were considered to be subversive. The Church tended to be suspicious of natural magic, for example, even though natural magic was simply concerned with the demonstrable properties of material bodies (such as the ability of magnets to attract iron or the ability of certain plants or their extracts to cure diseases). One way or another, therefore, the powerful combination of Aristotelian teachings with Church doctrines tended to exclude direct study and analysis of nature.