NURTURE AND NATURE 5 



correlation 1 . Taking the social conditions we wish to modify, we 

 must study their correlation with as many factors as we can possibly 

 measure. In the choice of these factors we must of course be guided 

 by the reasonable probability of association and by the limits of 

 human life and energy. The correlations of a multiplicity of factors 

 being known we may justifiably assume that the factors with the 

 highest correlations are, among those dealt with by us, the most 

 important, and then the process of "partial correlation" will guide 

 us still further towards a final judgment of what fundamentally are 

 social cause and effect. 



We admit to the full that even then we may not have avoided all 

 danger of pitfalls, that we may have overlooked possible factors, and 

 that spurious correlation may have arisen from all sorts of disregarded 

 selective processes. The prudent statistician will always advance his 

 conclusions with a word of caution ; he will simply state that they are 

 those which reasonably follow from the data provided. But at the 

 same time he will not hesitate to proclaim that in the present state 

 of our knowledge the calculus of correlation is the sole rational and 

 effective method available for attacking these urgent social problems. 

 If that calculus throws no light, when properly applied, on social 

 dynamics, then the only solution is to develop a finer statistical 

 calculus ; no other instrument, least of all general reasoning with 

 appeal to social or moral pre judgments, can at present aid us in our 

 difficulties with regard to what makes for, and what mars national 

 fitness. Indeed we venture to go further and to assert that much of 

 the canon of social conduct and moral action as it has existed in the 

 past and as it widely exists at the present will be found inadequate 

 or even antisocial, when we understand more fully the manner in 

 which legislation, social custom, and philanthropy (in the old sense) 

 tend to modify the biological factors on which human progress so 

 largely depends. 



There is no one with the least biological knowledge who would 



1 The coefficient of correlation measures the amount of resemblance or association 

 between characteristics of individuals or of things; it is represented by a decimal 

 which lies between o and i. As the correlation coefficient rises to i we approach a 

 condition of absolute dependence. As it falls to o we approach a condition of absolute 

 independence. Thus the correlation between right and left femur in man is -96 which 

 is practically unity, i.e. almost perfect dependence as we should expect. The inheritance 

 between stature of father and son is -51, half-way between absolute dependence and 

 absolute independence. 



