156 THE PHILOSOPHY OF BIOLOGY 



of his vocal mechanisms. Actions that have been 

 learned endure ; in some way cerebral and spinal 

 tracts and connections become established and persist : 

 undoubtedly when a cerebral lesion destroys or 

 impairs memory it is these physical nerve tracts and 

 cells that become affected. But in addition to this 

 we have pure memory (Bergson's " souvenir pur "). 

 What, for instance, is the visual image of some thing 

 seen in the past, which most people can form, but pure 

 recollection ? 1 



All the past experience of the organism — all its 

 perceptions, and all the actions it has performed — 

 endures, either as motor habits or mechanisms, or as 

 pure memories. All this need not be present in its 

 consciousness ; the motor habits would not, of course, 

 and only so much of the past would be recalled as 

 would be relevant to the choice which the organism 

 was about to make of the many kinds of responses 

 possible to its motor organisations. Out of this past 

 it would select all that was connected in any way with 

 the actions which were possible to it in the present. 

 It would recall all actions previously performed which 

 resembled the one provisionally decided upon ; but 

 recalling also the other circumstances associated with 

 those past actions, it would discover something which 

 would lead it to modify that provisional action. Now 

 in describing the whole behaviour of the acting organism 

 in this way are we doing any more than simply ex- 

 pressing in more precise terms the " commonsense ' 

 notions of the ordinary person ? The latter would sum 

 up all this discussion by saying that what he would 

 do in any set of circumstance depended not only on 

 the circumstances themselves but upon his experience. 



1 A visual image may, of course, be something that has never been actually 

 seen. But then its elements have had actual perceptual existence in the past. 



