Aristotle on sleep and dreams 191
Homer, in the well-known metaphor of the gates of horn and ivory in the
Odyssey( 19. 560 ff.), which distinguishes between true and false dreams, and
in the Hippocratic workOn Regimenquoted above, which differentiates
between dreams of a divine origin and dreams that have a physical origin.^32
However, these counter-arguments based on a classification of dreams into
different categories would not impress Aristotle: it is clearly inconceivable
for him that a god incidentally andad hocuses a natural phenomenon to
serve a purpose which is different from its normal, natural goal.
On the other hand, the passage also shows that Aristotle does not simply
confine himself to a rejection of a divine origin of dreams: his criticism is
directed against the specific assumption of dreams being ‘sent’ by the gods,
of divine messages being ‘sent’ through the medium of dreams. But that does
not imply that the phenomenon is deprived of any divine aspect whatsoever.
In the sentence ‘they are beyond human control, for the nature (of the
dreamer) is beyond human control, though not divine’ he recognises that
dreams still have something ‘super-human’ because the natural constitution
of the dreamer, which is the cause of the dream, is itself something beyond
human control. It appears from another passage, in the preface toOn Sleep
and Wakingquoted above, that the worddaimoniosis not to be understood
in the sense of ‘sent by demons’, but in the sense of ‘beyond human control’
(the opposite, so to speak, of ‘human’,anthropinos ̄ ): what appears to us in
a dream is beyond our control, just as it is beyond our control what kind
of natural, physiological constitution we have.
It may incidentally be observed that the structure of Aristotle’s argument
here is strikingly similar to that found in the Hippocratic worksOn the
Sacred DiseaseandAirs, Waters, Places(see chapter 1 above). In the former
treatise, the author rejects the view that epilepsy is sent by the gods, and
one of the arguments he produces is concerned with the distribution of
the disease among different kinds of people, which he claims is different
from what one would expect if it were sent by a god. Thus in 2. 4 – 5 he
says: ‘Here is another indication that this disease is in no way more divine
than the others: it affects the naturally phlegmatic, but not those who
are choleric. Yet if it were more divine than other diseases, it would have
to occur with all sorts of people in equal manner and make no distinction
between phlegmatic and choleric.’ And inAirs, Waters, Places 22 , the author
argues against the belief in the supernatural origin of impotence among the
Scythians, again by pointing out that the actual distribution of the affliction
(predominantly among wealthy people, who can afford horses) is exactly
(^32) On this distinction see van der Eijk ( 2004 a).