Aristotle on sleep and dreams 201
However, a similar problem presents itself further down in the text, when
Aristotle considers yet another possible explanation for the phenomenon
of divination in sleep; and again the difficulty arises while accommo-
dating the view of another thinker, in this case the atomist philosopher
Democritus.
6 a democritean element
As for dreams that do not have origins of the nature we just described, but origins
that are extravagant in time, place or size, or in none of these respects but without
those who see the dream having the origin in themselves – if foresight of the
future [in these cases] does not occur as a result of coincidence, the explanation
is more likely to be as follows than as Democritus says, who adduces idols and
emanations as causes. Just as when something sets water in motion or air, and this
moves something else, and when the one has stopped exercising motion, such a
movement continues until it reaches a certain point where the original moving
agent is not present, likewise nothing prevents a certain movement and sense-
perception from arriving at the dreaming souls, proceeding from the objects from
which Democritus says the idols and the emanations proceed, and in whatever
way they arrive, [nothing prevents them from being] more clearly perceptible at
night because during the day they are scattered more easily – for at night the air
is less turbulent because there is less wind at night – and from bringing about
sense-perception in the body because of sleep, for the same reason that we also
perceive small movements inside us better when we are asleep than when we are
awake. These movements cause appearances, on the basis of which people foresee
the future even about these things. (Div. somn. 464 a 6 – 19 )
Unfortunately, we do not have much information on Democritus’ views on
prophetic dreams that would allow us to check what Aristotle is attributing
to him,^53 but it seems that Aristotle is largely sympathetic to it, though with
the adaptation that instead of Democritus’ ‘idols and emanations’ (eidola ̄
kai aporrhoiai) he favours ‘movements’ (kin ̄eseis) as the mediating factors.
Furthermore, Aristotle says explicitly that the explanation offered for these
‘extravagant’ cases of foresight is built on the assumption that they are not
due to coincidence (
% "3
3 +). Thus
he is offering an alternative explanation for cases of foresight which earlier
on he attributed to coincidence ( 463 b 1 – 11 ) – and this was apparently also
what Democritus was doing. The experiences mentioned here are clearly
derived from sources outside the dreamer’s body, which emit ‘movements’
that, after travelling over a great distance, reach the soul in sleep; and they
can do so more easily at night because, Aristotle says, there is less wind
(^53) See van der Eijk ( 1994 ) 310 – 12 for a discussion and fuller references.