A Thirteenth-Century Perspective on Optical Science and Experiment: The Case of Roger Bacon

Roger Bacon (ca. 1214–1292), the English Franciscan Scholastic natural philosopher, introduced in his main works a new system for acquiring natural knowledge, which was at the heart of his proposed reform of the university curriculum. This system, scientia experimentalis, elevated knowledge gained through the senses, through experimentum, alongside knowledge from texts or first principles. According to Bacon, scientia experimentalis could yield a new future of Christian dominion, characterized in part by the machines and optical devices this new way of knowing fostered. Optics — the science of visual perception — was central to Bacon’s vision for this epistemic transformation, as it enabled both the understanding of observed phenomena and the creation of lenses and devices that were of enormous practical and rhetorical utility. This talk explores Bacon’s theory of scientia experimentalis, introduces the scholars whose work in this area strongly influenced him, and explores the role of optics in Bacon’s schema, concluding with some thoughts on what we might take from Bacon today.
 
Speaker Bio
 
Elly Truitt is a professor in the History and Sociology of Science Department at the University of Pennsylvania. This lecture derives from her forthcoming second book, Marvelous Inventions: Roger Bacon, the Middle Ages, and the Making of Modern Science. Her first book, Medieval Robots: Mechanism, Magic, Nature, and Art (2015), explored the history of automata in medieval Latin culture, where they appeared as gifts from foreign rulers in Baghdad and Damascus and at the courts of Constantinople and Shengdu. It demonstrated that artificial people and animals were ubiquitous in medieval culture, and that they were used to pose questions about identity, liveliness, and the ethics of knowledge and creation. Prof. Truitt is currently also working on a third book, in which different secular and religious courts (Latin Christian, Byzantine, Islamicate) between 750 and 1300 appear as case studies to explore the extent to which the natural knowledge pursued at courts — such as engineering, navigation, alchemy, and divination — was valued alongside text-based natural philosophical frameworks.