380 THE POPULAR SCIENCE MONTHLY. 



must have an important influence on the development of the train, 

 and hence also of the mind of which the brain is the organ. 



Whatever differences of opinion may exist as to certain minor 

 points in the physiology of the brain, all agree that it is organ- 

 ized on the same general plan as are the lower parts of the nerv- 

 ous system, and as are the entire nervous systems of those simple 

 animals whose functions consist in feeble sensations which arouse 

 equally feeble movements ; and as there are no abrupt transitions 

 either in the animal series or in individual development, so in the 

 nervous system of man there is no abrupt introduction of mental 

 conditions of a kind totally different from those which prevail at 

 a lower plane of animal life, but rather the foundations of all 

 mental processes are to be found in simple reflex actions. The 

 mental building material is, therefore, derived from movements 

 as well as from sensations ; and a sensation and its associated 

 movement may be said to constitute the psychical unit of the 

 whole mental life, as a sensory and motor nerve with their con- 

 necting center constitute the structural unit of the entire nervous 

 system. 



It is argued by Prof. Bain* that it is by the experience of 

 muscular exertion that we obtain our first real knowledge of the 

 external world — a " not-me " as opposed to the " me " of passive 

 sensation. Mr. Herbert Spencer also describes our fundamental 

 conception of matter as of something which offers resistance.! 

 The different degrees of resistance met with from the " not-me " 

 calling out different degrees of muscular effort, there arises a 

 sense of discrimination which is the beginning of knowledge. 



The duration of a muscular act also leaves its impression as a 

 distinct element of consciousness; and the continuance of the 

 mental state which accompanies this duration becomes a measure 

 of time, the idea of which is thus incorporated in our mental 

 make-up from the very dawn of consciousness. 



The origin of the perception of space is similarly traced, in 

 part at least, to movements ; especially the idea of linear extension, 

 which is greater or less in any given case according to the degree 

 of contraction involved in moving the limbs through space, taken 

 in connection with the time occupied. It is, then, largely by 

 these fundamental modes of what may be termed muscular dis- 

 crimination that we acquire our ideas of matter, of time and of 

 space— the classic triad of "innate ideas" of the intuitionists. 

 These supposed innate ideas being, however, susceptible of a 

 psycho-physical explanation, we are bound by the law of parsi- 

 mony to accept it. J 



* See " The Senses and the Intellect," by Prof. Alexander Bain, M. A. 



f See " First Principles." 



% The view advocated by Prof. W. James (see "Mind," 188*7), that all sensations have 



