Natural Knowledge in the Latin Middle Ages 89sisted that, in fulfi lling his mandate of supplying the missing explanation,
the physicus was doing nothing contrary to Genesis.^27
William of Conches’s contemporaries understood what he meant by
physica: “investigating the causes of things in their effects and the ef-
fects from the causes.”^28 Not everyone liked it, however. One opponent
attacked his “philosophical, or better, physical” approach to the Biblical
account of creation.^29 Even John of Salisbury thought that some of “the
physici... exalt beyond measure the power of nature” and went too far in
disputing about the soul, the resurrection, and creation—to the detriment
of the faith. Others disliked the physicus’s skepticism about miracles.^30 The
times were changing. Augustine had valued the liberal arts in order to un-
derstand scripture (as did his followers). For William, however, scripture
did not explain how the world came to be. This lacuna called for physica, a
causal natural philosophy. He was not shy in castigating his critics: “Igno-
rant themselves of the forces of nature and wanting to have company in
their ignorance, they do not want people to look into anything; they want
us to believe like peasants and not ask the reason behind things.”^31
In the Roman and early medieval worlds, natural philosophy had been
a taxonomic rubric more than a full- blown body of knowledge. By the
early twelfth century, natural philosophy emerged as a program for the
causal explanation of nature and developed some content. To twelfth-
century eyes, Plato’s Timaeus was particularly exciting: his use of Pythago-
rean ratios, triangles, and Platonic solids to explain the origins of the cos-
mos made him the natural philosopher of the era. The pump was primed:
between 1140 and 1180, a massive infl ux of works recently translated
from the Arabic fi lled the category of natural philosophy with so much
new content that it was overfl owing.
Meanwhile, drawing on his own exposure to Arabic learning, Adelard
of Bath was adding new depth to the quadrivium, to which contempo-
raries paid scant attention.^32 Adelard’s early- twelfth- century translation
of Euclid’s Elements replaced the fragments of the Boethian translation.
Along with the new vision of a causal natural philosophy, scholars now
had access to the archetype of an axiomatic, deductive, mathematical sys-
tem, and to the crucial prerequisite for understanding astronomy, optics,
and mechanics.
NEW CLASSIFICATIONS OF LEARNING: FROM ARTES TO SCIENTIAE
Early on, Adelard of Bath had advocated reliance on reason rather than
authority (understood as bookish learning and as revelation), and had in-