86 THE RELATIVITY OF ALL KNOWLEDGE. 



chemical actions which distinguish the food? Whence it 

 becomes manifest, that while Life in its simplest form is the 

 correspondence of certain inner physico-chemical actions 

 with certain outer physico-chemical actions, each advance to 

 a higher form of Life consists in a better preservation of 

 this primary correspondence by the establishment of other 

 correspondences. 



Divesting this conception of all superfluities and reduc- 

 ing it to its most abstract shape, we see that Life is definable 

 as the continuous adjustment of internal relations to exter- 

 nal relations. And when we so define it, we discover that 

 the physical and the psychical life are equally comprehended 

 by the definition. We perceive that this which we call In- 

 telligence, shows itself when the external relations to which 

 the internal ones are adjusted, begin to be numerous, com- 

 plex, and -remote in time or space; that every advance in 

 Intelligence essentially consists in the establishment of 

 more varied, more complete, and more involved adjust- 

 ments; and that even the highest achievements of science 

 are resolvable into mental relations of co-existence and se- 

 quence, so co-ordinated as exactly to tally with certain re- 

 lations of co-existence and sequence that occur externally. 

 A caterpillar, wandering at random and at length finding its 

 way on to a plant having a certain odour, begins to eat has 

 inside of it an organic relation between a particu- 

 lar impression and a particular set of actions, an- 

 swering to the relation outside of it, between scent 

 and nutriment. The sparrow, guided by the more 

 complex correlation of impressions which the colour, form, 

 and movements of the caterpillar gave it; and guided also 

 by other correlations which measure the position and dis- 

 tance of the caterpillar; adjusts certain correlated muscular 

 movements in such way as to seize the caterpillar. Through 

 a much greater distance in space is the hawk, hovering 

 above, affected by the relations of shape and motion which 

 the sparrow presents; and the much more complicated and 



