40 THE PHILOSOPHY OF BIOLOGY 



than the sensori-motor system are the basis of our 

 actions, but the memory images are, so to speak, 

 pressed back into that part of our organisation which 

 does not emerge into consciousness. Only so much of 

 them as bear on the situation in which we, for the 

 moment, find ourselves and which may therefore 

 influence our actions, flash out into consciousness. 

 As " dreamers " we indulge ourselves in the luxury 

 of becoming conscious of these memory images, but 

 as " men of action " we sternly repress them, or so 

 much of them as do not assist us in the actions that 

 we are performing. Yet it is in the experience of each 

 of us that, in spite of this continual inhibition, parts of 

 our memories slip through the barriers of utility and 

 surreptitiously remind us of all that we have been 

 and thought. 



Thus we simplify the stream of our consciousness. 

 That of which we are conscious at any time is never 

 more than a part of our crude sensation : we never 

 perceive more than a small part of all that our organs 

 of sense transmit to our central nervous system. 

 But even these chosen perceptions of the external 

 world are so rich, so chaotic and confused, that we 

 are unable to attend to them all at once and we there- 

 fore " skeletonise " the contents of our consciousness. 

 We think about it a bit at a time. It is an unitary 

 thing, unable to be broken up, but we look at it from 

 a great number of different points of view, so to speak ; 

 and then, fixing our attention on some aspect of it, we 

 agree to ignore all the rest. We thus detach parts of 

 it from the rest and, having thus arbitrarily decomposed 

 it, we call these separate aspects the elements of our 

 perceptions, and confer upon them separate existence 



