336 Animal Life and Intelligence. 



of the dog the world of Newton from the world of 

 Diamond ! 



And we must remember that it is not merely that the 

 same world is differently mirrored in different minds, but 

 that they are two different worlds. If there is any truth 

 in what I have urged in the last chapter, we construct the 

 world that we see. The sensations are, as we have seen, 

 mental facts, in no sense resembling their causes, but 

 representing them in mental symbolism. Percepts are the 

 elaborated products of this mental symbolism. The 

 question, then, is not How does the world mirror itself in 

 the mind of the dog ? but rather How far does the symbolic 

 world of the dog resemble the symbolic world of man ? 

 How far is his symbolism the same as ours ? Only by 

 fully grasping the fact that the external world of objects 

 does not exist independently of us (though something 

 exists which we thus symbolize), shall we realize the great- 

 ness of the difficulty which stands in the path of the student 

 of animal psychology. So long as we are content to accept 

 John Bunyan's crude analogy of the gateways of sense, the 

 difficulty is comparatively small. There is the outside 

 world self-existent and independent ; a knowledge of it 

 comes into the mind through the five gateways of sense 

 a picture of it through the eye-gate, and so on. The dog 

 has also five similar gateways. The world for him is, 

 therefore, much the same as for us. But this is not a true 

 analogy. The world we see around us is a joint product 

 of an external existence, the independent nature of which 

 we can never know, and the human mind. It is something 

 we construct, in mental symbolism. How far does the dog 

 construct a similar world? The answer to this question 

 must, as it seems to me, be largely speculative. 



And what help have we towards answering it ? That 

 afforded by the theory of organic evolution. If we accept 

 that theory, and accept also the view that mental or 

 psychical products are the inseparable concomitants of 

 certain organic or physiological processes, then we have a 

 basis from which to start. That basis I adopt. 



