SUMMARY AND CONCLUSION 315 



we concluded that their analogical method was unsatisfactory, 

 also that the biometric method of the Galton Eugenics Laboratory 

 had not as yet yielded conclusive evidence as to the relative in- 

 fluence of " nature " and " nurture," because the data were 

 unreliable and because of the inherent difficulty of separating 

 these two factors. Evidence brought forward in later chapters 

 has tended to confirm this conclusion and to leave us in uncer- 

 tainty as to whether or not progress from the far distant period of 

 the Neanderthal and Cro-Magnon types of man has been in native 

 mental ability or merely in somatic variations in the line of or- 

 ganic adaptation to geographical environment, and in acquired 

 intellectual and moral qualities transmitted by social heredity. 

 The arguments of the neo-Darwinian sociologists are too largely 

 deductive and analogical to be conclusive, whereas at least some 

 of the evidence produced by the environmental school is inductive 

 and indisputable. The former to a large extent have made the 

 cardinal mistake of assuming that the different races of mankind 

 are analogous to biological species whereas at present the con- 

 sensus of opinion is that there is but one species, while the term 

 "race" has no definite connotation. Evidence concerning the 

 difference in social instincts, keenness of sense perception, and 

 intellectual and emotional qualities between primitive and 

 modern man is so conflicting as to counsel moderation of state- 

 ment rather than dogmatism. The evidence on the whole, how- 

 ever, indicates that as there have been somatic variations mak- 

 ing for better adaptation to life conditions, especially in the 

 decrease in the size of the mandibles, in pigmentation and accli- 

 mation, so there have been variations in the nervous system 

 and brain tissue making for greater adaptation to the conditions 

 of existence and success imposed by modern life in civilized 

 nations. Differences in individuals are unquestioned, but when 

 the group is made the sociological unit the standard of ability is no 

 longer individual but social, and we have no sure word concerning 

 the native ability of the average in any civilized nation today as 

 compared with the average in any primitive group now extant or 

 that ever existed. No two groups come into competition now, 

 and never have, so far as we know, under such conditions that we 



