Natural Knowledge in the Classical World 55understandable, mind you, but itself capable of reasoning—and therefore
alive. There are hints of these ideas in some passages in Aristotle (and
some of his predecessors), but only hints, never fully developed. It is only
later, in Stoicism, that all the consequences of the equation of divinity and
order get fully explored, and it is through physics that this rational order
is found: theology is again a consequence of sophisticated physical inves-
tigation. The complex order demonstrated by the motions of the planets
and stars, for example, betrays the hand of a creator, far superior in ability
and wisdom to humans, and it does this so obviously that to doubt the
divinity behind it would be like doubting the existence of the sun, as the
great statesman and philosopher Cicero would put it not long before the
assassination of Julius Caesar.^42
Again, the Epicureans disagreed, limiting causation strictly to physical
interaction between atoms (plus the infamous “swerve”). Gods existed,
but they did not interfere in the universe except insofar as they provided
models of virtue for humans to contemplate. This emphasis on physical
causation and bracketing of divinity may look on the face of it more like
the disciplines we now think of as “scientifi c,” but there was a curious
upshot: other than arguments about the most basic levels of causation,
Epicureans did not tend to engage in what we would think of as scientifi c
investigation—we have no long list of prominent Epicurean anatomists,
geometers, biologists, or astronomers. Via ethics, Epicurean physics has
made overly careful scientifi c observation essentially irrelevant. Epicurus’s
treatment of astronomy, for example, makes it clear that minute investi-
gation in the sciences was beyond the scope of atomism, because atom-
ism was ultimately an ethically driven philosophy.^43 The observation and
explanation of the actual motions of the stars was irrelevant to the main
aim of the school, which was after all to provide for human happiness.
So long as the philosopher could be sure that some causal mechanism
was at play, he need not trouble himself about precisely why or how the
stars moved. Detailed empirical investigation could, in this sense, hang
itself. This looks to be a curious result, that a billiard- ball physics which
bracketed the gods out of the cosmos should turn away from an emphasis
on too close an investigation into nature, while the highly theologized
versions such as Aristotle’s and Galen’s should produce such a profound
curiosity about the tiniest details of nature. We should further note that
these theological arguments cannot be seen as attempts by ancient reli-
gion to provide justifi cations for itself, since ancient religion was really a
very different animal to what we are seeing here. Ancient religion was not
highly theologized, but instead stressed ritual devotion rather than intel-
lectual awe. What we have here is a philosophically motivated and em-