THE BIOLOGY OF HEALTH 130 



physico-chemical bustle that goes on in the nervous 

 system is the other aspect of the same reality. The two 

 aspects are inseparable, like the concave and the convex 

 surfaces of a dome ; but no metaphor is of any use, the 

 relation is quite unique. 



This is one of the oldest of riddles, and Tennyson 

 made " The Ancient Sage " say : — 



Thou canst not prove that thou art body alone, 

 Nor canst thou prove that thou art spirit alone, 

 Nor canst thou prove that thou art both in one : 



For nothing worthy proving can be proven, 

 Nor yet disproven. 



Yet three things seem to us to be quite certain : 

 (1) Our nervous system is a scientific actuality that can 

 be measured and weighed ; it is complex beyond our 

 power of conception, if only because of the millions of 

 living units which it includes ; it is the seat of an extra- 

 ordinary activity which baffles our imagination. No 

 theoretical view can stand that is subversive of the funda- 

 mental reality of our nervous system. (2) Even more 

 real, however, if there are degrees of reality, is our inner 

 life of consciousness, our stream of thoughts and feelings, 

 desires and purposes. It is our supreme reality, 

 for it includes all others, and no theoretical view can 

 stand that is subversive of this reality. (3) But the 

 third certainty is that organism and personality, body 

 and mind, nervous metabolism and consciousness, are 

 in the experience of everyday life interdependent. 

 If it is a relation, there is nothing to which we can 



