Aristotle on the matter of mind 211
when, inGen. an. 5. 7 , he says that he has been discussing those aspects
of voice that have not yet been dealt with inOn the SoulandOn Sense
Perception.^15
Yet not always can differences in Aristotle’s treatment of a particular soul
power at different places be so easily related to the principles or strate-
gies underlying the arrangement of his biological works. To continue with
the example of sense-perception, there is a discrepancy between his rather
formal and abstract enunciations on visual perception inDe an. 2. 7 (the
‘canonical’ doctrine of sight being moved by the visible object through the
medium of the transparent) and, on the other hand, his rather technical
discussions of various forms and degrees of sharpness of sightKSDR +L
and seeing over a great distance inGen. an. 5 , and of observing certain
cosmic phenomena such as haloes as a result of reflectionK"
Lin
Meteorologica 3 , which seem to presuppose an emanatory view on visual
perception consisting in visual ‘rays’ departing from the eye and reaching
the object of sight (or failing to do so properly). Even if this ‘emanatory’
doctrine is not identical to the view that Aristotle seems to reject inOn
Sense PerceptionandOn the Soul, it remains unclear how it is to be accom-
modated within the ‘canonical’ theory of visual perception expounded in
those works.^16
In general, one gets the impression that divergences like this^17 tend to
occur when Aristotle is dealing with the more ‘technical’ or ‘mechanical’
aspects of how soul powers actually operate and how, in particular cases or
circumstances, these operations maydeviatefrom the normal procedure.
In dealing with these deviations, Aristotle sometimes refers to physical or
physiological mechanisms or entities in respect of which it is not quite clear
how they fit in the general picture or what part, if any, they play in thenormal
procedure. Thus in the example of visual perception over great distances,
Aristotle does not explain what atmospheric conditions are conducive to
the process of the object setting the visual faculty in motion, resulting in
successful seeing. Similarly with regard to the ‘type’ of the melancholics^18
- one of Aristotle’s favourite examples of deviations in the area of action
(^15788) a 34 -b 2. As for the relationship between ‘psychology’ and ‘biology’ in Aristotle, it would be
interesting to examine the relationship betweenGen. an. 5 on the one hand andOn the Souland
On Sense Perceptionon the other; the many references in the former to the latter ( 786 b 23 ff.; 781
a 21 ; 779 b 22 ) should indicate that Aristotle is very much aware of possible differences in levels of
explanation or in status of the psychic phenomena to be discussed in either of these works.
(^16) On this problem see van der Eijk ( 1994 ) 183 and 189 – 91.
(^17) Other examples are Aristotle’s discussion of the central sense faculty inDe an. 3. 2 ,Sens. 6 andSomn.
vig. 2 , or his doctrine of the ‘kindled soul’ inDe iuv. 469 b 16 andResp. 474 b 13 , or the problem of
animal intelligence (see below and Coles ( 1997 )).
(^18) See ch. 5 in this volume.