XXVII HUMAN PROGRESS : PAST AND FUTURE 501 



cannot get direct proof, then the probability which arises 

 from all the phenomena being such as would occur if the 

 theory in question were true, and this so completely as to 

 give us the power of predicting what will occur under new 

 and hitherto untried conditions. Of this nature is the 

 probability in favour of the existence of an ethereal medium 

 whose undulations produce light and heat ; of atoms which 

 combine to form the molecules of the various elements ; 

 and of the molecular theory of gases. The biologists of 

 Europe, though usually slow to accept new theories in 

 the place of old ones, have given to the theories of Weis- 

 mann and Galton an amount of acceptance which was 

 never accorded to Darwin's theory of Pangenesis, notwith- 

 standing the weight of his great reputation ; and they are 

 now seeking earnestly for facts which shall serve as 

 crucial tests of the rival theories, just as the phenomena 

 of interference served as a test of the rival theories of 

 light. 



We have here only to deal with the theory of the non- 

 inheritance of acquired characters as it affects mental and 

 moral qualities ; and in this department it has to encounter 

 great opposition, because it seems to bar the way against any 

 improvement of the race by means of education. If the 

 theory is a true one, it certainly proves that it is not by 

 the direct road of education, as usually understood, that 

 humanity has advanced and must advance, although edu- 

 cation may, in an indirect manner, be an important factor 

 of progress. Let us, however, look at the problem as pre- 

 sented by the rival theories, and see what light is thrown 

 upon it by the history of those great men who have most 

 contributed to the advance of civilization, and who serve 

 well to illustrate the successive high-water marks attained 

 by human genius. 



Illustrations of the Non- inheritance of Ciolture. 



If progress is in any important degree dependent on the 

 hereditary transmission of the effects of culture, as distin- 

 guished from the transmission of innate genius, or of the 

 various talents and aptitudes with which men and women 



