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 Maupertuis clearly merits a place of some distinction. For he was the possessor of a wide view of the interrelation of different scientific problems; 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?[1] This question he answered in a pessimistic sense, in an age when a superficial optimism was the proper note among enlightened 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.
