From the Beginning to Plato

FROM THE BEGINNING TO PLATO 207
atomists assigned some role to chance in the causation of events, though
precisely what role is not easy to determine. Aristotle (Physics 196a24–8, DK 68
A 69), Simplicius (Physics 327.24–6, DK 68 A 67; 330.14–20, DK 68 A 68) and
Themistius (Physics 49.13–16 (not in DK)) all say that Democritus attributed the
formation of every primal cosmic swirl to chance (indeed Aristotle finds a special
absurdity in the theory that while events in a cosmos occur in regular causal
sequences, the cosmos itself comes into being purely by chance). Cicero (On the
Nature of the Gods I.24.66, DK 67 A 11) says that heaven and earth come into
existence ‘without any compulsion of nature, but by their [i.e. the atoms’] chance
concurrence’, while Lactantius (Divine Institutions I.2.1–2, DK 68 A 70) baldly
attributes to Democritus and Epicurus the view that ‘everything happens or
comes about fortuitously’. Aetius I.29.7: ‘Democritus and the Stoics say that it
[i.e. chance] is a cause which is unclear to human reason’ may be read either as
asserting or as denying that Democritus believed that there are genuinely chance
events. Read in the latter way it attributes to Democritus the view that we explain
an event as due to chance when its real cause is unknown; on the former reading
the view attributed to Democritus is that chance is itself a real cause of events,
but an unfathomable one (the position mentioned by Aristotle without attribution
at Physics 19605–7). A passage from Epicurus’ On Nature (fr. 34.30 in
Arrighetti), which one might hope to be our most authoritative source, is
similarly ambiguous. There Epicurus describes the atomists as ‘making necessity
and chance responsible for everything’, a formulation which is ambiguous
between two positions; (1) ‘necessity’ and ‘chance’ are two names for a single
universal cause, (2) necessity and chance are distinct but jointly exhaustive
causes of everything. 4
The passage of Lactantius is of little weight; he states that the fundamental
question is whether the world is governed by providence or whether everything
happens by chance, and says that Epicurus and Democritus held the latter view. It
is plausible that he took their denial of providence to commit them to that view,
since he himself took those alternatives to be exhaustive. This passage, then,
gives no independent ground for the attribution to either philosopher of the thesis
that literally everything happens by chance.
We are still, however, left with those passages attesting Democritus’ belief that
every cosmic swirl, and therefore every cosmos, come into being by chance.
That might be thought to be confirmed by the statement in Diogenes Laertius’
summary of Democritus’ cosmology that he identified the cosmic swirl itself
with necessity (IX.45, DK 68 A 1). On this interpretation the statement that
everything happens by necessity is confined to events within a cosmos, and
states that all such events are determined by the atomic motions constituting the
swirl. The swirl itself, however, is not determined by itself, nor by anything; it
just happens. Eusebius (Praeparatio Evangelica XIV.23.2, DK 68 A 43) also
reports Democritus as ascribing the formation of worlds to chance, and goes
further by reporting him as holding that the pre-cosmic motion of the atoms was
also random (‘these atoms travel in the void hōs etuchen (literally “as it