212 Aristotle and his school
and cognition – we are told that they suffer from certain disturbances in
their recollective capacities because of the presence of moisture around their
‘perceptual parts’,^19 but we are not informed about thenormalphysiological
conditions for a successful operation of the recollective faculty.
One reason for this may be that Aristotle believed his audience to be
sufficiently aware of these physical or physiological processes, perhaps be-
cause they were part of a medico-physiological tradition which he took for
granted,^20 or he may not have quite made up his mind on them himself;
in both cases, lack of clarity in the texts^21 prevents us from seeing how all
these brief references to physiological processes fit together and are to be
accommodated within the more ‘formal’ account ofOn the Soul, in which
the emphasis is, as I said, on what ensouled beings havein commonand
in which deviations are rarely considered (although they are occasionally
taken into account in passing in that treatise as well, as inDe an. 421 a 22 ff.,
to be discussed below).
However, it would also seem that these discrepancies are, at least partly,
the result of a fundamental tension in Aristotle’s application of the concept
of ‘nature’K -
L, that is, what it means for the psychic functions to
operate ‘naturally’K1 -
L. On the one hand, there is what we might
call his ‘normative’ (or perhaps ‘idealistic’) view of what it naturally means
to be a living plant, animal or human being – an approach which dominates
inOn the Souland in theEthics. On the other hand, there is also a more
‘technical’ or perhaps ‘relativistic’ perspective, in which he is concerned
with the mechanics of psychic processes and with a natural explanation
of thevariationsthat manifest themselves in the actual performance of
psychic functions among different living beings (e.g. degrees of accuracy
in sense-perception, degrees of intelligence, degrees of moral excellence).
Thus from the one perspective he might say that every human being is
intelligent by definition, but from the other that not all human beings are
equally intelligent, or from the one perspective that all animals have sense-
perception by definition, but from the other that not all animals possess all
senses. Whilst some of these variations exist between different species (e.g.
some species of animals have only one sense, touch, whereas others have
more), others exist between individual members of one species or between
differenttypeswithin one species (thus Aristotle distinguishes, within the
human species, types such as the melancholics, dwarfs, ‘ecstatic’ people,
(^19) Mem. 453 a 19 ff.
(^20) This seems to be the case with his concept of the melancholics; see ch. 5 in this volume.
(^21) On the general lack of clarity of physiological descriptions in theParva naturaliasee Lloyd ( 1978 )
229.