288 THE SCIENCE OF LOGIC 



Take the case of mortality statistics. A series of deaths is 

 not a phenomenon of precisely the same sort as the drawing of 

 a series of cards from a pack. Each particular death the death 

 of this particular person at this particular time and place is 

 the necessary outcome of certain (partially known and partially 

 unknown) natural causes, operating detrimentally in his organism ; 

 or it may be the inevitable result of a complex concurrence of 

 natural causes culminating in a fatal accident. The drawing of 

 this particular card from the pack is likewise determined by the 

 concurrence of a number of unknown natural causes. The dif 

 ference is not in the individual cases : it lies in this, that while 

 the general set of antecedents does not vary in the case of draw 

 ing a series of cards, it may vary considerably in a series of 

 deaths. The number of deaths per year in any country depends 

 on many and variable factors ; and, consequently, the average 

 number of deaths during any period of years furnish a very 

 uncertain basis for conjecturing the average number during 

 another period of the same duration. In Belgium, for example, 

 the average age of the inhabitants in 1829 was 31 years 5 

 months; in 1856, 38 years I month; in 1890, 45 years I 

 month. 1 



Tables of mortality form part of the basis on which the 

 business of life insurance companies is conducted. Yet those 

 tables are recognized as only rough approximations to any real 

 constancy : the actuaries take care to revise and readjust their 

 tables frequently, in order to keep them in agreement with the 

 actual facts. 



There is still more reason for caution in making any attempt 

 to explain phenomena of the psychological, moral, or social orders 

 by statistics and averages, or to erect such statistical uniformities 

 into laws? During the last century great hopes were aroused of 

 reading the secrets of moral and social phenomena by the appli 

 cation of statistics to their domain. In his Essai de physique 

 sociale, published in 1839, Qu6telet proposed to himself to study, 

 by their consequences, &quot; the natural causes, whether favourable 

 or unfavourable, that influence the development of man&quot;. The 

 initiative of this able Belgian scholar opened up the way to a 

 number of highly interesting but extremely delicate researches. 

 He himself brought his observations to bear on the age at which 



1 MANSION, op. eit., p. 32. J C/. WELTON, op. cit., ii., p. 198. 



