180 Aristotle and his school
built on observation of ‘the facts surrounding sleep’ ( 459 a 24 ), and his
claims are backed up by a much more considerable amount of empirical
evidence:
1. There is no sense-perception in sleep ( 458 b 7 ; but see nos. 23 and 24 below).
2. During sleep, we often have thoughts accompanying the dream-images ( 458 b
13 – 15 ); this appears most clearly when we try to remember our dreams imme-
diately after awakening ( 458 b 18 – 23 ).
3. When one moves from a sunny place into the shade, one cannot see anything
for some time ( 459 b 10 – 11 ).
4. When one looks at a particular colour for a long time and then turns one’s
glance to another object, this object seems to have the colour one has been
looking at ( 459 b 11 – 13 ).
5. When one has looked into the sun or at a brilliant object and subsequently
closes one’s eyes, one still sees the light for some time: at first, it still has the
original colour, then it becomes crimson, then purple, then black, and then it
disappears ( 459 b 13 – 18 ).
6. When one turns one’s gaze from moving objects (e.g. fast flowing rivers),
objects that are at rest seem to be moving ( 459 b 18 – 20 ).
7. When one has been exposed to strong sounds for a long time, one becomes
deaf, and after smelling very strong odours one’s power of smelling is impaired
( 459 b 20 – 2 ).
8. When a menstruating woman looks into a mirror, a red stain occurs on the
surface of the mirror, which is difficult to remove, especially from new mirrors
( 459 b 23 – 460 a 23 ).^24
9. Wine and unguents quickly acquire the odours of objects near to them ( 460 a
26 – 32 ).(^24) For a full discussion of this extraordinary claim see van der Eijk ( 1994 ) 167 – 93 with more detailed
bibliographical references (to which should now be added Woolf ( 1999 ), who arrives at a very similar
view to mine about the passage being illuminating for Aristotle’s views on material alteration in sense-
perception). While in earlier scholarship the authenticity of the passage was disputed, the discussion
now focuses on the following issues: ( 1 ) the problem of the passage’s obvious counterfactuality; ( 2 )
is the theory of menstruation as expounded here in accordance with what Aristotle says elsewhere?
( 3 ) is the theory of something emanating from the eye not inconsistent with Aristotle’s views on
visual perception as stated elsewhere? ( 4 ) What is the point of the passage for the discussion of the
way in which dreams come into existence? Briefly summarised, my view is ( 1 ) that what seems to
be underlying the passage is a traditional belief (perhaps derived from magic or midwives’ tales) in
the dangerous and polluting effects of menstrual blood, and that Aristotle must have accepted this
story without checking it because he felt able to provide an explanation for it; such beliefs were not
uncommon regarding menstruation (although most of the evidence dates from the Roman period);
( 2 ) there is no inconsistency regarding the cause of menstruation, for in 460 a 6 – 7 the words
1
% /
must be connected with8
> > > '# 8 (pace
Dean-Jones ( 1987 ) 256 – 7 ); ( 3 ) there is no inconsistency, for Aristotle is not discussing perception
but reflection, in which the eye is not the perceiving subject but the object that sets the process in
motion and brings the reflection about; ( 4 ) the passage illustrates (a) the swiftness and acuteness
of the senses, which allows them to register even the tiniest differences and changes, and (b) the
lingering of such tiny perceptions after the impression has been made. It is these lingering, tiny
movements that constitute the material for dreams.