FACTS AND FACTORS OF DEVELOPMENT 35 



memory, instincts, intelligence and will ; the continuity of consciousness 

 is associated with the continuity of these activities, as well as with the 

 structures of the body in general and of the brain in particular. It is 

 well known that things which interrupt or destroy these functions or 

 structures interrupt or destroy consciousness. Lack of oxygen, anes- 

 thetics, normal sleep cause in some way a temporary interruption of 

 these functions and consequently temporary loss of consciousness ; while 

 certain injuries or diseases of the brain which bring about the destruc- 

 tion of certain centers or association tracts may cause permanent loss of 

 consciousness. 



The development of all of these psychical faculties runs parallel 

 with the development of bodily structures and apparently the method of 

 development in the two cases is similar, viz., progressive differentiation 

 of complex and specialized structures and functions from relatively 

 simple and generalized beginnings. Indeed the entire organism — struc- 

 ture and function body and mind — is a unity, and the only justification 

 for dealing with these constituents of the organism as if they were sepa- 

 rate entities, whether they be regarded in their adult condition or in the 

 course of their development, is to be found in the increased convenience 

 and effectiveness of such separate treatment. 



Development, like many other vital phenomena, may be considered 

 from several different points of view, such as (1) physico-chemical 

 events involved, (2) physiological processes, (3) morphological charac- 

 ters, (4) ecological correlations and adaptations, (5) psychological 

 phenomena, (6) social and moral developments. All of these phases of 

 development are correlated, indeed they are parts of one general process, 

 and a complete account of this process must include them all. General 

 considerations may lead us to the belief that each of the succeeding 

 aspects of development named above may be causally explained in terms 

 of the preceding ones, and hence all be reducible to physics and chem- 

 istry. But this is not now demonstrable and may not be true. Function 

 and structure may be related causally, or they may be two aspects of one 

 substance. The same is true of body and mind or of matter and energy. 

 But even if each of these different phases in the development of person- 

 ality may not be causally explained by the preceding ones, at least the 

 principle of explanation employed for any aspect of development ought 

 to be consistent and harmonious with that employed for any other aspect. 



The phenomena of mental development in man and other animals 

 may be summarized in the following table : 



Development of Psychical Processes in Ontogeny and Phylogeny 



All Living Things, including Germ Mature Forms of Higher Animals 



Cells and Embryos, show: show: 



1. Differential Sensitivity = 1. Special Senses and Sensations = 



Different Eesponses to Stimuli Sensations are the Elements of 



differing in Kind or Quantity. Mind. 



