52 Lehoux
[the heart] they fall outward against the surface of the vein itself and permit
a free fl ow by opening the orifi ce wide and to its greatest extent. If, however,
there is a fl ow from outside back in again, this very fl ow pushes the valves
together so that they overlap each other and make of themselves a gate, as it
were, perfectly sealed... For Nature certainly did not wish to tire the heart
with useless labour by causing it sometimes to send material out when it is
supposed to be coming in from some part of the body, or to draw material in
when it is supposed to be going out to some part.^36And so, part by part, structure by structure, he explores the entire body
over the course of two very large volumes.
Why such thoroughness? In part it is complete for completeness’
sake—a fl urry of almost superhuman virtuosity—but it is also framed as
an argument against a rival interpretation of the body, and indeed of the
universe as a whole, that of the Epicurean atomists. Where I have been
arguing in this chapter for a general teleological and theological frame
to ancient science, I have not been telling the whole story. There was a
good degree of diversity of opinion on many matters, some fi ne grained
(the function of the veins, mechanism of the nerves, precise value for the
equinoctial year, physical makeup of the moon) and some more general.
Indeed, by Galen’s day there were a wide range of philosophical schools
to choose from, Stoicism, Platonism (whose proponents were called “Aca-
demics” after Plato’s “Academy”), Aristotelianism (“Peripatetics”), Epicu-
reanism, or even Scepticism and Cynicism. Many of these schools agreed
on many points, teleology and theology crossing many boundaries in this
respect. But some schools blocked even this move, Epicureans, by the Ro-
man period, very prominent among them.
As we saw briefl y above, the Epicurean universe was made up of at-
oms separated from each other by spaces of pure nothingness, pure void
(an idea that would see an interesting revival in the early- modern pe-
riod).^37 Atoms interacted only by crashing into each other, and all physical
phenomena that we encounter in the macroscopic world are caused ulti-
mately by thousands upon thousands of these tiny collisions. This chaos
of crashing atoms, combined with a technical detail of Epicurean physics
called the swerve (an occasional randomness that affects the motion of
some atoms at some times), meant that the particular combinations of
atoms that we see—dogs, trees, stars, rocks—could perfectly well have
happened otherwise. There is, in short, no intervening deity (although the
Epicureans did insist on the existence of gods, they qualifi ed it by arguing
that the gods did not interfere at all in the functioning of the universe—
such concern would be beneath them). It is to this randomness argument,