ANIMAL BEHAVIOUR 219 



brainless animals without using words like selecting, trying, 

 learning, and profiting by experience. We cannot demon- 

 strate the existence of consciousness in the lower animals, but, 

 as Professor Jennings observes, " objective investigation is 

 as favourable to the view of the general distribution of con- 

 sciousness throughout animals as it could well be " (1906, 

 p. 337). " So far as objective evidence goes there is no 

 difference in kind, but a complete continuity between the 

 behaviour of lower and of higher organisms " (1906, p. 335). 

 We start at one end with our own doings, in some of 

 which intelligence counts, we pass gradually, though never 

 perhaps by rigid demonstration, through the behaviour of 

 our fellows, our horses and dogs, birds and fishes, spiders 

 and hermit-crabs, ganglionless starfishes and sea-anemones, 

 to the extraordinarily puzzling condensed individualities of 

 Infusorians and Amoeba?. Nor will it be easy to shut out 

 carnivorous plants and others that stir themselves in what 

 seems to us a sleep-life, whose dreams are flowers. At all 

 levels of organisation we find behaviour which, objectively 

 considered, is like our intelligent behaviour. We know that 

 in many cases the creatures are not so clever as they look, 

 and we do not know of any way of proving that mentality 

 pervades it all. But it is impossible to think of intelligently 

 controlled behaviour evolving from behaviour in which men- 

 tality was wholly absent, and it seems clearest to think of 

 all organisms as psycho-physical individualities. 



(3) Third we get a vivid impression that the realm of 

 organisms stands out in strong relief against the inorganic 

 background. The not-living world is a domain of mechanical 

 necessitation, without initiatives; a domain of uniformities, 

 without alternatives; a domain of absolute determination, 

 without spontaneity; a domain where there is no individu- 



