[ SI ] 



XIV. Some Jccount of the Life and IVrillngs of CoNDORCiiT, 

 By M. Lacroix*. 



Jean Antoine Nicolas Caritat, Marquis de Condorcet, 

 one of the most distinguished philosophers of th.e eighteenth 

 century, commenced the study of the mathematics with very 

 great success, never lost sight of them, hut attached himself 

 principally to the diiTusion of knowledge in general, and to the 

 discussion of the most important subjects in social (leconomy. 

 His father, descended from an ancient family in the Venaissin, 

 resided in the Castle of Ribeinont in Picardv. Here Condorcet 

 was born on the 17th of September 1743, and came in 175S to 

 study philosophy at the college of Navarre : there he sustained a 

 thesis in mathematics, in presence of Clairaut, D'Alembert, and 

 Fontaine, who judged him worthy of one day taking his place 

 among them. In 1762 he settled at Paris, with his old pro- 

 fessor of philosophy Giraud de Keroudou, in order to give him- 

 self up entirely to the mathematics. Soon afterwards he con- 

 nected himself with Fontaine, a geometrician endowed with 

 great sagacity, but whose singular character and strange habits 

 had prevented his progress. It was the peculiar doctrine of 

 Fontaine that Condorcet proposed to develop and extend in his 

 Essay on the Integral Calculus, the first of his works ; but the- 

 Theory of the Equations of Condition, with which he commenced 

 at the age of twenty, gave him a very distinguished rank, since 

 we there find the demonstration of several important theorems, 

 which Euler had met with by chance only, and the direct proof 

 of which he regarded as being very difficult. The remainder 

 of this w^ork, containing only general ideas, which require to be 

 fixed and even proved by applications, announced much sagacity, 

 and a profound knowledge of his subject, but left too much to 

 be done in the details to enable us to derive any advantage 

 from it. He afterwards treated in the same spirit the Problem 

 of the Three Bodies, of which he was the first to give equations 

 at once general and completely symmetrical ; but he did not 

 stop to particularize them, in order to render them accessible to 

 the methods of approximation, and contented himself with de- 

 veloping the spirit of these methods, and the precautious which 

 their use requires : " i\Iy object (he says) is to give general ]iriii- 

 ciples, wdthout entering into details which should facilitate to 

 others routes which I have not the courage to pursue." These 

 words, which escaped !iim, would seem to indicate a sort of scien- 

 tific egotism : but such an interpretation would he quite unfair 

 so far as Condorcet is concerned, who desired nothing so much 



* Mas,usin Enci/cloi'edique for Nmember 1313, p. i4. 

 Vol. 44. No. 19G. August 1814. F as 



