336 ADAPTIVENESS AND PURPOSIVENESS 



occasion of a great flood, and so on, we say, with probable 

 accuracy, that the creature was actuated by a definite pur- 

 pose, by some sort of intention, by some anticipation of an 

 end. The validity of this undemonstrable conclusion de- 

 pends (1) on the need of assuming some degree of purpose 

 as the connecting thread which binds together the series of 

 acts, and (2) on what we know in other ways of the creature's 

 psychological analogy with ourselves. If the acts composing 

 the chain are discontinuous, the need for postulating a bond 

 of purpose is particularly evident If the creature has a 

 fine brain at a high structural level, as we know to be the 

 case with dogs, horses, elephants, and the like, the legitimacy 

 of inferring an actuating purpose is the more probable. It 

 may well be that the purpose is not of the same nature as 

 our purpose when we begin a day with the intention of 

 economising our energies at every turn for a difficult task 

 to-morrow, or of converting as many people as possible to an 

 acceptance of methodological vitalism. It may be that the 

 animal's ' purpose ' is only a concrete picture with an asso- 

 ciated desire, a cognitive disposition at a perceptual level 

 and an associated conative disposition. So it is sometimes 

 in mankind, especially in childhood. But it will still be 

 legitimate to describe the behaviour as purposeful, though 

 the purpose was not a conceived purpose. For we mean by 

 purpose an intention of the organism, involving a perceptual 

 or conceptual anticipation of a desired end. 



Difficulties in making sure that an actuating purpose is 

 at work begin whenever we pass from ourselves to our 

 neighbours ; they increase when we pass to big-brained higher 

 animals; they go on increasing when we pass to cases like 

 that of a bird building a nest. The bird goes through a 

 certain routine of collecting and interweaving materials, 



