EIGHTEENTH CENTURY EVOLUTIONISTS. 241 



to be rehabilitated. He was by no means a great scientific investigator ; 

 his work in physics and in astronomy, which he professed for his chief 

 specialties, seems to be of decidedly questionable accuracy and value. 

 His celebrated 'law of least action,' which was the original occasion of 

 his quarrel with Koenig and Voltaire, was a generalization vaguely 

 conceived and ill formulated, although, as Mach has pointed out, it 

 was taken up by Euler, the friend and partisan of Maupertuis, and 

 transformed into an important physical principle. But in any history 

 of the general movement of scientific thought in his century Mauper- 

 tuis clearly merits a place of some distinction. For he was the pos- 

 sessor of a wide view of the interrelation of different scientific prob- 

 lems; he was an ingenious and yet often a pretty shrewd and critical 

 interpreter of the bearing and ulterior consequences of the scientific 

 discoveries of others; and he contributed to more than one branch of 

 science new and important conceptions, which during the subsequent 

 century and a half have come into great vogue and in some cases into 

 general acceptance. 



As was the fashion of his time, Maupertuis took philosophy as well 

 as physical science for his province; and before considering his work 

 in the latter domain, it is worth noting that in the former also he was 

 the proposer of several notions, now familiar enough, which were at 

 the time relatively novel and contrary to the prevailing intellectual 

 fashions. As a moralist, for example, Maupertuis raised a question 

 that has been repeated with much doleful iteration by his nineteenth 

 century successors, but one highly paradoxical to his contemporaries: 

 In ordinary human life, does the sum of dissatisfactions exceed the sum 

 of pleasures?* This question he answered in a pessimistic sense, in 

 an age when a superficial optimism was the proper note among enlight- 

 ened philosophes — and was reproached for it by the writer who, a few 

 years later, was to produce the 'Poem on the Lisbon Disaster' and 

 'Candide. ' In laying down the logical conditions for dealing with 

 such a question, Maupertuis anticipated Bentham and the 'moral 

 arithmetic' of the Utilitarians, by elaborating a species of hedonic 

 calculus, in which careful definitions are offered, not only of the nature 

 of pleasure and pain, but also of the several dimensions of each that 

 must be reckoned in assessing the relative value of any two 'sums of 

 pleasure,' or of its contrary. As a political theorist, also, he shows 

 himself a precursor of the English Utilitarian school, at a time when 

 nearly all the new systems of political philosophy were based upon some 

 form of the conception of 'natural rights' or 'natural law.' In his 

 'Eloge de M. de Montesquieu' he criticizes the political doctrine of 

 the 'Esprit des Lois,' which rests, he says, upon the assumption that 

 there inheres in human relations 'un certain rapport d'equite' which 

 man's reason immediately recognizes. "It is not," writes Maupertuis, 



* ' Essai de philosophie morale,' chaps. 1 and 2. 



