178 ANIMAL BEHAVIOUR 



to say, the description that we give of an animal's behaviour, 

 or of critical corners in it at least, is bound to be inadequate 

 unless we use psychical terms. This is the other extreme. 

 It was expressed by Hume when he said : " No truth appears 

 to be more evident than that beasts are endowed with thought 

 and reason as well as men." That may be tenable generosity 

 for horse and dog, but it cannot hold good for starfish and 

 earthworm. 



How are we to avoid the stern over-parsimony of Descartes 

 on the one hand, and the delicious over-generosity of Mon- 

 taigne on the other? We must not give a false simplicity 

 to the facts by reducing the animal to the level of an auto- 

 matic machine, but we must not read the man into the 

 beast without critical hesitation. The hive-bees that make 

 the honeycomb so symmetrically are not automatic machines, 

 but neither are they little geometricians. 



To keep to the via media of good sense must always be 

 difficult, for the assumption of mind in an animal or of a 

 psychological aspect in the behaviour of an animal cannot 

 be demonstrated. There is no litmus paper for mentality. 

 " Every statement," says Bethe, " that another being pos- 

 sesses psychic qualities is a conclusion from analogy, not a 

 certainty ; it is a matter of faith." Our assumption of mind 

 in our fellow-men rests on the same sort of basis (though 

 with inter-subjective corroborations) ; it is a necessary hy- 

 pothesis and one that works. Is not a similar hypothesis 

 indispensable in regard to animals if we are to understand 

 them and make the most of them? But animal behaviour 

 has such a long gamut that each case must be judged on 

 its own merits. We ask in each case whether we can make 

 sense of what we see without assuming mental factors, 

 whether we can adequately describe what we see without 



