CHAF. XIL] SENSATION, IDEATION, AND .PERCEPTION. 169 



of ' Eeflex Action and Unconscious Cognition,' will be 

 found to be a fully justifiable procedure, and it was equally 

 desirable that its consideration should have been prefaced 

 by an enquiry as to the scope of ' Mind ' and the nature 

 of mental phenomena. 



Descartes, Leibnitz, Spinosa, and other philosophers 

 have, as Sir William Hamilton reminds us, been led to 

 regard "the faculty of Cognition as the fundamental 

 power of mind from which all others are derivative ; " 

 while Condillac and his school attributed this rank to 

 Sensation rather than to Cognition, and similarly derived 

 all other mental faculties from this as a base or starting 

 point. 



It would not be in accordance with the point of view 

 of Evolutionists to say that either of these faculties could 

 generate all the others. If we grant it to be true, that one 

 or other of them either Cognition or Sensation does, 

 in fact, constitute the primary manifestation of mental 

 activity, we should rather say, that as the nervous actions 

 upon which the mental process is dependent grow more 

 complex, so may other so-called ' faculties ' of mind be 

 gradually engendered as related phases of the same neu- 

 rological activity, and marked by a growing tendency to 

 become more and more distinct from one another. 



As to which of the mental modes or manifestations is 

 to be regarded as primary, there seems to us to be little 

 room for doubt. Hamilton truly observes* : " The 

 faculty of knowledge is certainly the first in order, inas- 

 much as it is the conditio sine qua non of the others ; and 

 we are able to conceive a being possessed of the power of 

 recognizing existence, and yet wholly void of all feeling of 

 pain and pleasure, and of all powers of desire and voli- 

 tion. On the other hand, we are wholly unable to con- 



* " Lectures on Metaphysics." Fifth Edition, vol. i., p. 188. 



