ANIMAL AND RATIONAL INTELLIGENCE 221 



these two modes of knowing, must be constantly in 

 view. Strict guard must be kept against encroach 

 ment of the one mode into the province of the other, 

 such as might induce easy acceptance of analogies 

 in procedure of the lower and higher life. The need 

 for this guard has been long insisted upon in the 

 interests of physiology ; it must now be insisted upon 

 in the interests of psychology. 



The results of our training of animals must afford 

 the main test of their intelligence. Though there is 

 no evidence that animals, even the highest mammals, 

 interpret their own sensory experience, we have 

 ample proof that the higher animals are capable of 

 interpreting signs, for direction of their action. This 

 is obvious in the case of the horse, the dog, the 

 monkey, and the ape. This capability places these 

 animals in closer relation with man, than proves 

 possible for lower orders. After scrutinising in detail 

 the whole circle of evidence, 1 we observe this limita 

 tion, that the exercise of animal intelligence is 

 connected with direction of animal activity, not with 

 acquisition of knowledge. Of this apparent restric 

 tion, explanation may be sought in our mode of obser 

 vation, which is restricted to the actions of animals. 

 But this explanation is clearly insufficient. The 

 limitation is in the scope of the activity observed. 

 Call the animal into action, and its intelligence 

 becomes apparent. Leave the animal to itself, and 

 signs of intelligence are either wanting, or are com 

 paratively rare. As instinct always concerns forms of 

 action, so it is here. When intelligence appears in 



1 For this, I must refer again to The Relations of Mind and 

 Brain, chap. vii. 



