The Middle Ages still suffers from the embarrassment of comparison. Before it glowed the light of the ancient Greeks – the great, early speculators of the natural world and our place in it. After the Middle Ages came the scientific revolution – Copernicus, Galileo, Newton – and the surging onrush of modernity. Even if the idea of the so-called ‘dark ages’ is waning, there remains the widespread impression that the Middle Ages is in some sense a time of stagnancy, especially in its understanding of science and the natural world. Is this an accurate view of medieval science? There is one discipline, often overlooked, that serves to illuminate the Middle Ages, as well as its place in the history of scientific thought: mechanics.
The predominant assumption about the rise of modern science is that it went hand in hand with the conception of nature as a universal mechanism. By viewing nature in this way, it could be studied, analysed and experimented upon with mathematical rigour, and its functioning could be elucidated by physicists harnessing empirical methods. While the motion of inanimate bodies became theorised on the model of projectiles, some mechanical philosophers even claimed that the complex organisation of animate bodies could be understood on the model of levers, springs, pulleys and other mechanical devices. This step – nature as a universal mechanism – is often seen as the important break from the Middle Ages.
From these historical facts, it will appear more clearly why and how the modern identification took place – explicitly stated by Galileo, Francis Bacon and René Descartes – of nature with a type of mechanism whose secrets must be investigated by the natural philosopher. The invention of mechanical clocks which, unlike most previous human inventions, did not require anything to keep moving once set in motion, had already modified the way philosophers conceived of nature with respect to machines. In the 14th century, Oresme compared the world to a clock, an analogy later taken up by Kepler in the 17th century. As early as the first half of the 13th century, John of Holywood had designated the Universe created by God as the ‘machine of the world’ (machina mundi). This expression, later quoted by Robert Grosseteste, Giovanni Pico della Mirandola, Nicholas of Cusa and Copernicus, was well known to the 16th-century commentators of the Mechanical Problems, including Galileo, who quotes John of Holywood in his lectures given in Padua.
