508 THE EVOLUTION OF MIND 



verbal jugglery. It. may also be said at the outset that if 

 the genetic view we adopt here results in suggesting that 

 animal behaviour is easy to understand or is a commonplace 

 affair, then it is being wrongly stated. Whatever view we 

 take as to the nature of mind and its relation to bodily ac- 

 tivity, it is a fact that as we follow the main line of animal 

 evolution, behaviour becomes more masterly, more plastic, 

 more like our own. As regards behaviour the slipper-animal- 

 cule is surpassed by the earthworm, the worm by the black- 

 bird, and the bird by the cat. There is increasing freedom, 

 subtlety, and resourcefulness of behaviour. Many will ad- 

 mit this at once, who will not take the further step of 

 supposing that the progressive evolution of behaviour is asso- 

 ciated with a clarifying and strengthening of what, by anal- 

 ogy with ourselves, we may call the stream of inner life — 

 the flow of feeling, will, and thought. We suppose that there 

 is a rill of inner life growing in volume until it becomes 

 a stream, because as we pass from lower to higher animals 

 there is more and more behaviour that we cannot fully de- 

 scribe in purely physiological terms. But before we think 

 tentatively of the stages in the evolution of behaviour, we 

 must give heed to some preliminary considerations. 



§ 2. Difficulty of Understanding the Process, 



First, we must try to avoid any facile reading of the man 

 into the beast. In ourselves we know that some stimulus 

 often sets agoing a vigorous internal activity of thought- 

 processes, involving an experimenting with imagery and play- 

 ing with centrally aroused sensations. This goes on in our 

 brain and it brings fatigue. It may be associated with 

 • movements in larynx and tongue, with speaking to ourselves, 

 and with changes in eyes and brow and heart; but there is 



