102 Shank
scrutiny of propositions using rigorous logical analysis that led Ockham
to conclude (among other things) that motion was not itself a thing, but
a name for the behavior of a thing.^89
Murdoch’s expression “natural philosophy without nature” nicely
makes the point that many medieval natural philosophers were more in-
terested in conceptual analysis than the direct observation of nature or ex-
perimentation.^90 A key feature of the enterprise in the fourteenth century
was the exploration of hypothetical scenarios, sometimes with surprising
results. After exploring the hypothetical rotation of Earth, Nicole Oresme
confessed that he could fi nd no compelling rational or empirical evidence
either to prove or to disprove it. He also analyzed the behavior of a stone
falling through a hypothetical tunnel along the diameter of Earth, con-
cluding that the stone would oscillate with a pendulum- like motion from
one side to the other.^91
If much medieval natural philosophy, like most theory today, was
bookish, not all of it was—to say nothing of medicine and the mathemati-
cal sciences. Some books testify to their authors’ wrestling with nature
through observation and experimentation. In the “science of plants,” the
“science of stones,” and the “science of animals” (considered by most as
belonging to natural philosophy), observation played a nontrivial role.
Knowledge acquired from local observation appears in Hildegard of Bin-
gen’s writings on fungi, birds, and animals from the Rhineland. Albertus
Magnus systematically observed the bat and experimented on the be-
havior of ants whose antennae he had removed—arguably the fi rst since
Theophrastus to take up Aristotle’s “causally oriented study of the ‘animals
and plants around us.’” A hunter who spent hours observing raptors and
their prey in their habitats, Holy Roman Emperor Frederick II (d. 1250)
criticized Aristotle in his detailed On the Art of Hunting with Birds. He also
studied avian anatomy and determined experimentally that vultures fi nd
carrion by sight, not smell.^92 Clearly, Aristotle was not treated as infallible.
His positions often framed the box, but fourteenth- century natural philos-
ophers also thought outside it. They criticized, and proposed alternatives
to, his views on many topics, from new rules of motion and explanations
of the acceleration of falling bodies to discussions of the possible rotation
of Earth, which he had held to be impossible.^93
The intermediate sciences relied on the book, but also went beyond it.
While most astronomi / astrologi could make predictions using only astro-
nomical tables in a windowless room, the minority who worried about the
foundations of the “science of the stars” did appeal to the sky. The new,
late- thirteenth- century Alfonsine Tables professes a rhetoric of long- term
observation in Spain, even though few new observations shaped them.^94