Mental Processes in Animals. 337 



Unfortunately, we have at present but little particular 

 knowledge of the correlation of psychical and physiological 

 processes. We cannot, by the dissection of a brain, draw 

 much in the way of valid and detailed inference as to the 

 nature of the psychical processes which accompany its 

 physiological action. Fortunately, however, on the other 

 hand, there are certain physical manifestations which do 

 aid us, and that not a little, in drawing inferences from 

 the physical to the mental. For organisms exhibit certain 

 activities, and from these activities we can infer to some 

 extent the character of the mental processes by which they 

 are prompted. We are wont, in observing the actions of 

 our fellow-men, to draw conclusions (often, alas ! erroneous) 

 as to the mental processes which accompany them. We 

 are ourselves active, and we are immediately conscious of 

 the modes of consciousness which accompany our actions. 

 Thus the activities of organisms give us some clue to their 

 mental processes, and it is through observation of their 

 physical activities that we gain nearly all that is of par- 

 ticular value concerning the mental activities of animals. 

 These activities we shall have to consider more fully in a 

 future chapter. In the present chapter we shall consider 

 them only so far as they give us information concerning 

 the perceptual world (or worlds) of animals, and the nature 

 of the inferences which we may suppose animals to draw 

 from the phenomena which fall within their observation. 



I think that, from the fundamental identity of life-stuff, 

 or protoplasm, in all forms of animal life, and from the 

 observed similarity of nerves and nerve-cells when nervous 

 tissue has been developed, and again from the essential 

 resemblance of life-processes in all animal organisms, we 

 are justified in believing that mental or conscious pro- 

 cesses, when they emerge, are essentially similar in kind. 

 Exactly when they do emerge in the ascending branches 

 of the great tree of animal life it is exceedingly difficult, 

 if not quite impossible, to determine. And it is, I fancy, 

 quite impossible for us so to divest ourselves of the com- 

 plexity of human consciousness as to imagine what the 



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