Historical periods are almost always introduced in hindsight, with some agenda. This is doubly true for ‘Middle Ages,’ a term we employed in previous chapters to designate the period after the fall of the Roman Empire. The millennium this term designates was far from being just ‘in the middle,’ and the people living through it experienced as many changes and upheavals as in any other era.

The movable press was a product and a harbinger of a new age of knowledge in Europe: commercial, expansive, urban, adventurous. It befitted a new world which was both much larger and much smaller: its horizons extended well beyond what could be imagined just decades earlier, but what lay beyond those horizons was now reachable and negotiable. Yet perhaps the most resounding impact of the press was close to home: it shook the foundations of the European institution of knowledge, the Catholic Church.

Disregard, for the moment, all you have been taught and consider the following question, relying only on what you have actually observed: when you look up at the sky, what do you see? The answer is not as straightforward as one might expect.

You may start by answering: ‘it depends.’ During the day, we see the Sun. During the night, we see the stars. Most of us live in cities, so we don’t see many of them, but it only takes a short ride out of town and a bright, moonless night to observe the sky as the ancients did: full of literally countless stars. The Moon is a bit of a mystery: although it usually appears during the night, we have all, on occasion, seen it by day.

Leaving the protective confines of the university for the glamour of the court ended up costing Galileo his freedom, but it wasn’t merely a reckless career move. Galileo did have a powerful idea of himself as a philosopher, making unreserved claims about the make-up of nature – claims that his university rank as a mathematician didn’t allow. Like Kepler, however, he didn’t intend to forsake mathematics for philosophy. His project, rather, was to submit the philosophy of nature to mathematics: to claim mathematical foundations for nature and thus designate the mathematician as its most skilled and authoritative interpreter.

Putting the experimental ideology of the Royal Society into practice was the role assigned to Robert Hooke (1635–1703) – perhaps the first person whose entire career was defined by the institutions and practices of the New Science he helped shape.

He was born on the Isle of Wight in the south of the English Channel to Cecil Gyles and her husband John Hooke, a Church of England priest. These were origins at once respectable and peripheral: on the Isle, his family was notable enough to move in the circles surrounding the court of the embattled King Charles when it found itself in exile there in 1647. When his father died in 1648, however, the 13-year-old Hooke took his small inheritance and went to London.

In 1599, when Galileo was starting to make a name for himself at the University of Padua, a young Cambridge graduate, William Harvey (1578–1657), arrived there to study medicine. Padua was one of the two most prestigious medical faculties in Europe (the other being Leiden), and known to admit non-Catholic students, providing them with special colleges, so an Englishman aspiring for a medical career in the metropolis was all but obliged to make the journey.

What happened to Greek knowledge? Not just the astronomy of Eudoxus, Eratosthenes and Hipparchus, but the natural philosophy of Aristotle and his disciples with its forays into what we’d call botany and zoology; the medicine of Hippocrates and Galen (to whom we’ll return in Chapter 8); the geography of Ptolemy; the mathematics of Euclid and Archimedes and much more – all that knowledge the longing memory of which Raphael captures so marvelously at the beginning of the sixteenth century (Figure 4.1) – and of which we now have only fragments or recollections of.

This is the Gothic cathedral, the marvel that inspired Ormond’s poem. The one in the picture (Figure 1.1) is perhaps the grandest of them all: the Notre Dame cathedral at Chartres, south-west of Paris. It is a breathtaking accomplishment: 130 meters in length, it would cover a Manhattan block and a half; its vaults are 37 meters in height, higher than a modern ten-story building; its southern, Romanesque tower is 107.5 meters tall, and the northern, Jehan de Beauce tower, 114 meters – a 30-storey skyscraper of “hewn rock … hoisted into heaven.”

Here is one thing that the masons building the cathedral and the scholars occupying its chapels would have agreed on: that the stones out of which it is constructed are heavy, and that there is nothing one can do about it. We can, of course, accommodate this heaviness. The scholars may try to understand why stones are heavy and what heaviness is; the masons may try to tackle it “with winch and pulley.” But both would agree that some things in the world are light and some are heavy, and no knowledge can change that.

The cathedral metaphor suggested an important distinction: between what its builders knew how to do – in order to erect the cathedral – and what they knew about the world – according to which they attempted to shape the cathedral. Going back in time, searching for the resources they drew on, we have also revealed the limits of the distinction: knowledge about the world, it turns out, is itself a kind of know-how. Both types of knowledge require skills, tools, materials; they involve recognizing problems and seeking solutions; searching for resources, adopting and adapting them to new use.