128 Hippocratic Corpus and Diocles of Carystus
also referred to asdianoia) as a distinct entity, separate from the body (soma ̄ ).
This distinction manifests itself in particular during sleep ( 4. 86 – 7 ). How-
ever, this does not imply that the soul is immaterial. The soul consists of wa-
ter and fire (the elements which, according to this author, have the greatest
influence on the constitution of the human body), which stand in a certain
proportion to each other. Fluctuations in this proportion result in differ-
ences between individual people’s cognitive skills, such as acuteness, a good
memory, precision of the senses and proneness to certain emotions ( 1. 35 ).
When the balance between these two elements is seriously disturbed, it will
give rise to psychological disorders, but these can be cured by changing eat-
ing and drinking habits and adopting a certain lifestyle ( 1. 36 ). According to
this author, the soul is therefore a material entity, yet it does not have a fixed
location: it moves through the body via ‘passages’ (poroi). The condition of
these passages (for instance their width or narrowness) is a further influential
factor in someone’s mental functioning. In the state of wakefulness, the soul
distributes itself over the entire body and carries out certain tasks ‘for the
benefit of the body’, including hearing, seeing, touching and movement.
During sleep, or rather ‘when the body is asleep’, the soul remains awake
and withdraws in its own ‘home’ (oikos), where it carries out the activities of
the body independently. These include seeing, hearing, walking, touching,
grieving, thinking: they are calledenhupniaor ‘dreams’. Yet the author does
not venture an opinion on the location of the soul and its ‘home’.
A presentation like this shows how inadequate terms like ‘materialism’
and ‘dualism’ are to describe ancient theories on body and mind. The author
ofOn Regimenmay be called a materialist to the extent that he holds an
entirely material view on the soul; yet at the same time he assumes two
separate entities which may normally co-operate and mutually influence
each other, yet one of them (the ‘soul’) can also function independently, as,
for instance, in sleep.^19
The greatest refinement in the definition of thestatusof mental phe-
nomena can be found in Aristotle, although his comments on the topic,
too, show a certain amount of fluctuation. He expresses the view that the
‘soul’ is not a separate entity, which might exist independently of the body:
‘soul’ to Aristotle is ‘the form of the body’, that which causes a body to live,
which gives it structure and enables it to exercise its faculties.^20 Yet this
(^19) For the psychology ofOn Regimensee Palm ( 1933 ) 44 – 7 ; Joly and Byl ( 1984 ) 296 – 7 ; Hankinson
( 1991 b) 200 – 6 ; Jouanna ( 1966 ) xv–xviii; Cambiano ( 1980 ) 87 – 96 ; Van Lieshout ( 1980 ) 100 – 3.
(^20) For this interpretation of Aristotle’s understanding of the soul see Sorabji ( 1974 ) 63 – 89 and Kahn
( 1966 ) 43 – 81 , both reprinted in Barnes, Schofield and Sorabji ( 1979 ) 42 – 64 and 1 – 31 ; van der Eijk
( 2000 b). For other attempts to reformulate Aristotle’s view on the mind–body debate in modern
terms see the volume by Nussbaum and Rorty ( 1992 ), with comprehensive bibliography.