Wrestling with Nature From Omens to Science

Natural Knowledge in the Classical World 51

tendons, the nerves) are still the same, and on many readings the analysis
from natural selection is no less teleological than Galen’s physiology of
the body had been.^33
In his pursuit of a complete analysis of Nature’s wisdom and benefi -
cence, Galen moved farther and farther into the body. His skill in fi nd-
ing, exposing, and analyzing the interior of the body, down to the very
limits of visibility (and beyond—he correctly argued for the existence of
invisible capillaries, for example) was unsurpassed for centuries before and
after (indeed, one testament to his stature is the fact that we have more
of his writings preserved—considerably more—than of any other ancient
Greek author).^34 His careful technique can be seen in his tracing of the
nerves to the larynx:

In the larynx there are three other pairs of muscles most necessary for the

production of the voice... Let us see, then, how perfectly Nature has pro-

vided for these two considerations: namely, supplying what was necessary

for [muscular] action, while avoiding the injustice of supplying inappropri-

ate nerves to the muscles. She decided to bring nerves down from the brain,

like the others I have spoken of earlier, by way of the sixth pair, from which

nerves must also be given to the heart, stomach, and liver, but to make them

run a sort of double course, carrying them fi rst to parts below the larynx,

and then bringing them back up again to its most important muscles. But

they could not run back without making a turn, so that Nature was forced

to seek a turning- post, so to speak, for the nerves around which she might

bend them.^35

Here we see the combination of very skilled observation (when Galen
traced the nerves responsible for the motion of particular muscles through
their complex paths) with his experimental physiological work (the deter-
mining of particular nerve functions in the fi rst place) all overarched by
his argument on the providence and foresight of Nature. In other inves-
tigations, the complexity is multiplied by the need to observe the func-
tioning of very deep organs without killing the anatomical subject. So his
description of the valves of the heart at the origin of the pulmonary artery
(which he calls the “arterial vein”):

They lie facing outward from within, surrounding the whole circumference

of the orifi ce, and each has such an accurate shape and size that when they

are all tensed and stand erect, they become a single large membrane sealing

the whole orifi ce. When they are opened by an outward fl ow from within