THE DESCENT OR OBIOIN OF MAN 189 



imperfect types, and to the skilful selection of the finest 

 individuals out of each successive generation"; tlie selection 

 relating only to the married state, and acting on all cor- 

 poreal, intellectual, and moral qualities." "We may, there- 

 fore, infer that sound and good men who, out of prudence, 

 remain for a time unmarried, do not suffer a high rate of 

 mortality. 



If the various checks specified in "the last two paragraphs, 

 and perhaps others as yet unknown, do not prevent the 

 reckless, the vicious, and otherwise inferior members of 

 society from increasing at a quicker rate than the better 

 class of men, the nation will retrograde, as has too often 

 occurred in the history of the world. We must remember 

 that progress is no invariable rule. It is very difficult to 

 say why one civilized nation rises, becomes more powerful, 

 and spreads more widely, than another; or why the same 

 nation progresses more quickly at one time than at another. 

 We can only say that it depends on an increase in the actual 

 number of the population, on the number of the men en- 

 dowed with high intellectual and moral faculties, as well 

 as on their standard of excellence. Corporeal structure ap- 

 pears to have little inff^ience, excej)t so far as vigor of body 

 leads to vigor of mind. 



It has_been urged by several writers, that as high intel- 

 lectual powers are advantageous to a nation, the old Greeks, 

 who stood some grades higher in intellect than any race that 

 has ever existed," ought, if the power of natural selection 

 were real, to have risen still higher in the scale, increased in 

 number, and stocked the whole of Europe. Here we have 

 the tacit assumption, so often made with respect to corporeal 

 structures, that there is some innate tendency toward con- 



" Dr. Duncan remarks ("Focundity, Fertility," etc., 1871, page 334) on 

 this subject: 



"At every age the healthy and beautiful go over from the unmarried side 

 to the married, leaving the unmarried columns crowded with the sickly and 

 unfortunate." 



"' See the ingenious and original argument on this subject by Mr. Galton, 

 "Hereditary Genius," pp. 340-342. 



