22 The Universe and Life 



pared to meet situations that have not yet arrived ; it 

 takes measures that avoid a later danger or that seize 

 a later benefit. The moUusk that reacts to a shadow as 

 it does to an attack, the rat that avoids a trap, the 

 author that prepares a paper for publication, the 

 statesman that guides a nation to a higher state of 

 culture — ^these illustrate those features of biological 

 material just described. 



Thus in the externally observable structures and 

 activities of organisms there are progressive changes 

 which lead to greater complexity, adequacy, adap- 

 tiveness. 



And along with these, closely correlated with them, 

 occur other changes that are discovered through the 

 fact that the biologist is himself a biological speci- 

 men ; through the fact that the biologist that studies 

 is a piece of the same material of which are composed 

 the living things that he studies. When in develop- 

 ment the organism reaches some degree of elabora- 

 tion, it has sensations, it feels. As development goes 

 farther and the living things become more complex 

 and diversified in structure, the sensations, feelings, 

 and other inner experiences also become more elabo- 

 rate and diversified. New mental experiences are 

 added; the mental experiences become in a high de- 

 gree complex and differentiated. These inner phe- 

 nomena are highly correlated, not only with the 

 physical make-up of the organism, but also with the 

 physical conditions and changes that act on the 

 organism from outside. A correspondence is induced 

 between these inner processes — that we can discover 



