CHAPTER XXI 



THE MENTAL OR COGITIC EVOLUTION OF MAN IN 

 RELATION TO THAT OF THE HIGHER ANIMALS 



Regarding mental states Hume has said (195): "All our per- 

 ceptions are dependent on our organs, and the disposition of 

 our nerves and animal spirits." In accordance with such a 

 century-old dictum, it will be our endeavor in the present chap- 

 ter to ascertain how perfectly even the most complex mental 

 processes can be traced back to simpler beginnings. For Ro- 

 manes has well remarked: "It belongs to the very essence of 

 evolution, considered as a process, that, when one order of 

 existence passes on to higher grades of excellence, it does so 

 upon the foundation already laid by the previous course of its 

 progress." 



In Chapter IV it was suggested that, amongst simplest non- 

 nucleate organisms or Acaryota, a more perfect or condensed 

 form of energy than electricity traversed and energized the 

 protoplasm. This we named biotic energy. Further we ad- 

 duced evidence for the persistence of this in all cell protoplasm, 

 but accepted it that, with the gradual evolution of nucleoprotein 

 and a nuclear mass, a still more evolved energy was increasingly 

 associated with the biotic, and which we termed the cognitic. 

 We considered that biotic energy exhibited itself amongst the 

 Acaryota in simple direct responses to such environal stimuli 

 as light, gravity, moisture, etc., so that a rather indefinite or 

 varying type of growth resulted, since a degree of direct re- 

 sponse at one time to one stimulus might be altered or reduced 

 in amount by another action at a later time. 



In contrast to the last and in more evolved connection, we 

 considered that cognitic energy gave to caryotic or nucleated 

 plants and simpler animals the capacity to receive a variety of 

 environal stimuli, to combine these often within the tissues, 



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