94 NATURAL SELECTION AND 



we refer to it those progressive manifestations 

 of Life in the vegetable, the animal and man 

 which we may classify as unconscious, conscious 

 and intellectual life and which probably de- 

 pend upon different degrees of spiritual influx." 1 

 'Now, if gravitation, cohesion, etc., are the 

 spiritual world, the ordinary man may well ask, 

 " Where is the non-spiritual world ? " and an 

 idealist philosopher, where such can be found, 

 will echo the question in a slightly different 

 tone. Nobody denies that gravitation, chemi- 

 cal affinity, life, consciousness, intelligence, re- 

 present an ascending scale. But if the word 

 "spiritual" be extended to the lowest of them, 

 does this mean anything very different from 

 extending the word " material " to the highest 

 of them ? There is, indeed, a difference be- 

 tween naming the ultimate principle of the uni- 

 verse from the higher end of the scale or from 

 the lower ; but it is a difference in ontological 

 theory and not on a question of physical causa- 

 tion, with which alone the biologist, as such, 

 has to deal. 



Leaving this matter for the present, let us 

 see what reasons Mr. Wallace has for rejecting 



1 Ibid. p. 476. 



