Medicine and philosophy - Classical Homeopathy Online

Aristotle on sleep and dreams 183these weaker movements, which escaped our attention in the waking state,get, so to speak, a second chance to ‘present themselves’ to the perceivingsubject. They are ‘reactivated’ and ‘come to the surface’ (461 a 3, 7). This isan operation of the faculty of ‘imagination’. The physiological picture tobe drawn for this process is not completely clear, but seems to be roughly asfollows. Aristotle thinks that apart from the peripheral sense-organs (eyes,ears, nose, etc.) there is also a central, co-ordinating sense-organ located inthe heart (the so-called ‘principle of perception’, 461 a 6, 31; 461 b 4). Hisview seems to be that, normally speaking, a sensitive impulse is transmittedfrom the peripheral sense-organs to the heart, where it is received, recordedand noticed, and co-ordinated with movements from other senses (461 a 31).The transmitting agency is probably the blood (although this is not quiteclear from the text). 26 In the waking state, the weaker sense-movements,which have arrived at the peripheral sense-organs during the waking state,are prevented from reaching the heart because of the competition withstronger movements; it is only in sleep, when the blood withdraws fromthe outer parts of the body to the inner parts, that they penetrate to theheart. The ‘perception’ or ‘noticing’ of these movements is dreaming in thestrict sense. Thus dreams originate from weak sense-movements, whichhave entered the sense-organs in the waking state, but which were notnoticed by the perceiving subject because of their weakness in comparisonwith stronger movements.By explaining the occurrence of dreams in this way, Aristotle managesto account for the fact that dreams often display many similarities withwhat the dreamer has experienced in the waking state (because they consistof movements received during the waking state), but that these elementsoften appear in a distorted, completely ‘unrealistic’ configuration due tothe physiological conditions that influence the transmission to the heart.In order to substantiate this explanation, Aristotle has to presuppose, first,that the sense-organs actually receive very slight movements and, second,that these small movements are being ‘preserved’ (sōizesthai, 461 a 25)inthesense-organs from the moment of their arrival (in the waking state) tothe moment of their transport to the heart and subsequent appearance insleep.When we look at our list of empirical ‘data’, we can see that numbers3–9 are used by Aristotle in order to illustrate the mechanism of ‘lingering’or ‘persisting’ sense-movements after the actual perception has disappeared;numbers 8–9 point to the receptivity of the sense-organs to small26 See 461 a 25 and b 11, 27. See van der Eijk (1994) 81–7 and, with reservations, Johansen (1998).