220 Aristotle and his school
is sometimes justified by means of the alleged etymological relation be-
tween
#and
,^46 and it occurs a number of times in
Aristotle’s works.^47 There is nothing to suggest that this should be un-
derstood in a metaphorical way; on the contrary, the reference to bodily
motion and to children who because of their structural state of motion
are not capable of thinking strongly suggests that Aristotle actually believes
that thinking emerges from the ‘coming to a standstill’ of a bodily pro-
cess. Where this coming to a standstill takes place (the heart?) and what
bodily factors are involved (the blood?) are not explained in any of these
texts.^48 Whether thoughts ‘emerge’ from the standing still of movements,
or whether thoughtbrings aboutthe standing still of images (e.g. by ab-
straction) remains unclear.^49 The physiological picture to be drawn with
the transition from having knowledge to using it, which is said to occur
at the transition from drunkenness (or sleep) to sobriety (or waking), is
also referred to in Aristotle’s discussion ofakrasiainEth. Nic. 1147 b 6 ff.,
where it is said: ‘The explanation of how the ignorance (which caused the
weak person’s action) is dissipatedK -
Land the weak person returns
to a state of knowing is the same as concerning a drunk and a sleeping
person, and it is not peculiar to this condition: it is to be obtained from
the physiologists.’ This physiological explanation is provided by scattered
remarks in Aristotle’s physical works and is conveniently summarised by
Tracy: ‘knowledge is acquired and activated only when the body, and the
sensory system in particular,calms down, being freed from disturbance and
brought to a state of stable equilibrium in all respects, that is, to a state of
maturity, health, sobriety and moral excellence. Some of these may be pro-
duced by natural processes alone; others, like health and moral excellence,
may require assistance from the physician and trainer, the moral guide and
statesman.’^50 As emerges fromOn Sleep and WakingandOn Dreams, one
of these ‘natural processes’ is the restoration of the balance between warm
and cold in the body which is brought about when the process of digestion
(the material cause of sleep) has been completed; another, which accom-
panies this, is the process of separation of blood into a thinner, clearer
part and a thicker, more troubled part;^51 and yet another (in the case of
(^46) See Plato,Phaedo 96 b 8.
(^47) SeeDe motu an. 701 a 27 ;An. post. 100 a 1 ff. and 15 ff.;Int. 16 b 20 ;De an. 407 a 32 – 3 .Cf.Pr. 956 b
39 ff.; 916 b 7 ff.
(^48) Except inPr. 916 b 7 ff., where, perhaps significantly, a disturbance in intellectual activity (
,
in this case reading) is attributed to the cooling effect of ‘pneumatic movements’ and melancholic
humours; a few lines later on, however, the intellect ($) is localised in the head ( 916 b 16 ).
(^49) Perhaps one should think of an act of viewing ( ) ) the relevant items in a confused whole; see
Insomn. 461 a 8 – 25 ;Div. somn. 464 b 7 – 16 (cf. 463 b 15 – 22 );Mem. 450 b 15 ff.
(^50) Tracy ( 1969 ) 276.
(^51) On the physiological explanation of sleep inSomn. vig. see Wiesner ( 1978 ).