38 Lehoux
not just by the methods of investigation, but also by the larger reasons
people saw themselves as having for investigating nature in the fi rst place.
Theological and ethical concerns played central roles for almost everyone,
though the specifi cs differed from person to person, as we shall see. Fi-
nally, as we approach the end of classical antiquity, we will see how it was
under the Roman Empire, in the work of two of antiquity’s most prolifi c
investigators—Claudius Ptolemy and his contemporary Galen—that this
intertwining of concerns produced some of the most sophisticated and
technical inquiry of the whole ancient period.THE WORLD ALL AROUND
The great fi rst- century CE Roman encyclopedist and polymath, Pliny the
Elder, composed a massive collection of as many facts as he could fi nd, all
in one book, called the Natural History,^1 often touted as the world’s oldest
extant encyclopedia. Immensely popular right through to the Renaissance
and beyond, it has in more recent times fallen into an unfortunate ob-
scurity among nonspecialist readers, an obscurity that belies its incredible
importance to the history of the sciences. Pliny begins this formidable
work with a defi nition, and at the same time a paean:The world, THIS (according to whatever other name you want to call the
heavens by which everything is embraced round), is rightly believed to be a
god, eternal, immeasurable, never born nor ever perishing. What is outside
its bounds is of no concern to men—nor is it even within the reach of the
human mind. It is sacred, eternal, immeasurable, everything in everything.
Indeed it is itself the everything, fi nite but as though infi nite, certain in
all things but as though uncertain, the whole within and without encom-
passed in itself, both the product of the nature of things, and the nature of
things itself.^2If we parse out the separate claims in this passage, we see that Pliny’s
universe is, among other things, (1) eternal (both unbeginning and un-
ending); (2) a fi nite but very large sphere (the outside of which is both
unknowable and irrelevant); (3) a complete whole (with strong under-
tones of it being a rational, or at least a rationally organized, whole); and
(4) a god.
None of these propositions is unique to Pliny, but then the combina-
tion of the four is not exactly universal either. Pliny, like many of his Ro-
man contemporaries, was a widely educated but also very individualistic