INTRODUCTORY. 15 



it certainly does admit of gradual development from a 

 zero level." 



But, as we have said, this is covertly to affirm the 

 very thing to be proved — that intellect can be gradually 

 developed from a zero level. We altogether deny that 

 it can, though a nature of a certain kind, existing ab 

 initio^ may only make its real nature plainly manifest 

 as impediments disappear and needful conditions for 

 its showing itself, become provided. No "order of 

 psychical being " is perceptible by us in itself, but only 

 through its effects ; and we know quite well (through 

 persons who, from accident or disease, are temporarily 

 or permanently deprived of speech or even reason) that 

 an "order of psychical being" may be certainly in 

 existence, and nevertheless unable, from accompanying 

 physical conditions, to make that existence manifest ; 

 while we also know (through the further education of 

 children already plainly intellectual) that one and the 

 same "order of psychical being" may become better 

 able to manifest its latent power through changes in its 

 environment, e.g., through education. Therefore the 

 indisputable fact that no " sudden leap " in individual 

 human evolution takes place, is an argument that the 

 same intellectual nature has existed from birth, and that 

 it is only changes in environmental agencies and bodily 

 growths — i.e. physical conditions — which have enabled 

 powers latent from the first, to more and more plainly 

 make themselves manifest. The fact that the psychical 

 differen(ie between the immature and the mature human 

 being is marked by no obvious and conspicuous interval, 

 while the difference between the psychical manifestations 



