Aristotle on sleep and dreams 171
discussed. For although Aristotle, within the scope of these short treatises,
covers an admirable amount of topics and aspects of the phenomenon of
dreaming with a sometimes striking degree of sophistication, it is at the
same time remarkable that some important aspects of dreaming are not
treated at all – aspects which are of interest not only to us, but also to
Aristotle’s contemporaries. Let me give two examples. (i) Aristotle does
not appear to be interested in the contents of dreams, in their narrative
structure or in the mechanism responsible for the sequence of events and
experiences that occur to the dreamer in a certain order. Nor does he pay
serious attention to the interpretation of dreams: he only makes some very
general remarks about this towards the end ( 464 b 9 – 16 ); he does not
specify the rules for a correct interpretation of dreams. Yet themeaningof
dreams was what the Greeks were most concerned with, and we know that
in Aristotle’s time there existed professional dream interpreters who used
highly elaborated techniques to establish the meaning of dreams.^8 (ii) A
further striking fact is that Aristotle hardly discusses the relation of dreams
with other mental processes during sleep, such as thinking and recollection.
He has little to say on questions such as: can we think in sleep? can we solve
mathematical problems in sleep? (a problem that attracted much attention
in later thought on dreams, e.g. in medieval Arabic dream theory). This lack
of interest calls for an explanation, for not only does experience evidently
suggest that these mental operations are possible in sleep, but there was also
a powerful tradition in Greek thought, widespread in Aristotle’s time, that
some mental operations, such as abstract thinking (nous), could function
better and more accurately in sleep than in the waking state, because they
were believed to be ‘set free’ in sleep from the restrictions posed by the soul’s
incorporation in the body. Why does Aristotle not address this issue?
Now, in response to this, one could argue that Aristotle was under no
constraint from earlier traditions to discuss these points, for early and clas-
sical Greek thought tends to display rather ambivalent attitudes to the
phenomenon of sleep, and in particular to whether we can exercise our
cognitive faculties in sleep. On the one hand, there was a strand in Greek
thought, especially in some medical circles, in which sleep was defined
negatively as the absence of a number of activities and abilities that are
characteristic of the waking life, such as sense-perception, movement, con-
sciousness and thinking. And as we shall see in a moment, Aristotle’s theory
of sleep shows strong similarities to this tradition. On the other hand, there
was also a strand in Greek thought, represented both in Orphic circles but
(^8) See del Corno ( 1982 ).