516 THE EVOLUTION OF MIND 



When we look back over the vaguely discerned succession 

 of modes of behaviour, we detect what may be called the 

 tactics of the evolutionary advance. At level after level, 

 there has been an organisation or automatisation or enregis- 

 tration of behaviour so that an organism can do things 

 effectively without having to think about it. The answer 

 comes pat, and there is an economy of time and life. In 

 reflex actions, tropisms, and instinctive behaviour we see 

 the activation of capacities which have become part of the 

 hereditary constitution. The great result has been that the 

 organism, freed from having to attend to and control these 

 organised activities, has been able to push on to finer issues. 

 As individuals we are aware of this result being attained 

 by habituation, but there is little warrant for supposing 

 that the successive organisations we have referred to have 

 arisen by the entailment of the results of often repeated 

 performance. We say this because we do not know how 

 it could be arranged, because we have no evidence of the 

 transmission of intelligent-habitual capacities, because some 

 of the most striking pieces of instinctive behaviour occur 

 only once in a lifetime, and for other reasons. 



How, then, could the successive organisations be accom- 

 plished ? The probable answer is that they are all due to 

 germinal variations in the direction of a complexified nerv- 

 ous system. New departures which have been called, from 

 the psychical side, ' inborn inspirations ' prompted changes 

 in behaviour, and these were tested and sifted in the indi- 

 vidual lifetime. For a time the germinal variation might 

 be in the direction of differentiating and integrating the 

 brain; for a time there might be a specialisation in the seat 

 of some particular activity; and again there might be varia- 

 tion leading to short-circuits. 



