CONDORCET. 



:o*dorcet. CONDORCET, Jean Antoine Nicolas de Cajii- 

 - *"v"" '**' tat, Marquis de, a celebrated mathematician and phi- 

 losopher, was descended of an ancient and noble family, 

 and was born at Eibemont in Picardy, on the 17th 

 of September 1743. He received his education at the 

 College of Navarre, where he was distinguished among 

 his fellow students for his ardour in the acquisition of 

 knowledge, and for his extreme partiality to mathema- 

 tical and physical pursuits. In the year 176*5, when 

 he was in the 2 2d year of his age, he published his 

 Traite du Calcul Integral, in which he proposed to 

 give a general method of determining the finite inte- 

 gral of a given differential equation, either for differences 

 infinitely small, or for finite differences. This work, 

 which is noticed in the History of the Academy for 1765, 

 (p. 54.) had the honour of being praised byDAlembert 

 and Bossut, who were employed by the Academy to 

 examine it. They stated that the greater part of the 

 methods were invented by Condorcet ; that it exhibited 

 a degree of knowledge rarely to be met with at so early 

 an age ; and that it afforded a presage of talents which 

 the approbation of the Academy could not fail to excite. 

 This work was followed by his Essais d' Analyse, in 

 four parts, the first of which was published in 1765, the 

 second in 1767, and the third in 1768. This work re- 

 lates principally to the system of the world, and to the 

 solution of the problem of three bodies ; but these sub- 

 jects, as La Lande has already remarked, are treated 

 with a generality which is insufficient for astronomy. 

 On the 8th March, 1 769, he was admitted into the Aca- 

 demy of Sciences as joint mechanician, and as associate 

 on the 22d December 1770 ; and in this situation he 

 formed a friendship with D'Alembert which lasted du- 

 ring his life. He was appointed, along with D'Alem- 

 bert and Bossut, to assist the celebrated Turgot in his 

 financial calculations; and about the same time he 

 wrote, under the title of Lettres du Labuureur, a reply 

 to Necker's essay on the corn laws, entitled De la Le- 

 gislation et du Commerce des Grains, and he published 

 an anonymous defence of the political sect to which he 

 had attached himself. This last work was entitled 

 Lettres d'un Theologien a sonsjils, and was intended as 

 an answer to the Abbe Sabbatier's Dictionnaire des Trois 

 sieclcs de notre Literature. It contains a great deal of 

 unmanly and illiberal abuse, directed against religion 

 and its ministers ; and, as if even this was not a suf- 

 ficient display of his opinions, he afterwards publish- 

 ed his Commentaire des Pensees de Pascal, which is 

 filled with the principles of the most determined athe- 

 ism. 



In 1773 he published, at Paris, the Eloges des Aca. 

 demiciens de V Academic Boyale des Sciences tnort de- 

 puis 1666 jusqu'en 1699. This work contains the lives 

 of Huygens, Picard, and Roemer, who were not inclu- 

 ded in the Eloges either of Fontenelle or D'Alembert, 

 and, if we believe La Lande, was written at a time 

 when he was ambitious of the secretaryship to the Aca- 

 demy of Sciences, and with the view of shewing that 

 he was qualified for that important office. Influenced 

 probably by the genius displayed in these eloges, as 

 well as by the high opinion entertained of him by 

 D Alembert, the Academy appointed him adjunct 

 secretary, with the reversion of that office, on the 10th 

 of March 1773. 



A vacancy having occurred in the French Academy 



by the death of M. Saurin, in 1782, Condorcet was 



proposed as a candidate by his friend D Alembert, while 



M. Bailly, the celebrated author of the History of Astro- 



nmy, was supported witli all the influence of the 



vor., VII. PART I. 



J13 



Count de Buffon. Bailly had been vanquished, at the Condorcet 

 last election, by M. Chamfort, by only three or four 

 votes, and was therefore supposed to have the best 

 chance of succeeding Saurin. D'Alembert, however, 

 employed all his address and activity in the cause of 

 his friend, and he at last succeeded in securing Con- 

 dorcet's election by the single vote of M. de Tressan, 

 at a meeting consisting of 31 members. This acade- 

 mician, who owed his place in the Academy to Buffon, 

 had promised his vote both to Bailly and Condorcet,' 

 but D'Alembert, who was more acquainted with human 

 character than Buffon, had the precaution of obtaining 

 a written promise from M. de Tressan, and of thus se- 

 curing a vote which might otherwise have decided the 

 election of Bailly. The discourse which Condorcet de- 

 livered to the Academy at his admission, does not appear 

 to have answered the high expectations of his friends. 

 It related principally to the rapid progress of know- 

 ledge during the 16th century, and to the doctrine of 

 the infinite perfectibility of the human mind, an opinion 

 which seems to have decayed with the revolutionary 

 spirit in which it had its origin, and which could be 

 maintained only by men who were intoxicated with a 

 false and extravagant estimate of their own powers. 



In the year 1778, when the Academy of Sciences at 

 Berlin proposed a prize for the best dissertation on the 

 theory of comets, Condorcet transmitted an essay, 

 which was however unsuccessful. It was published 

 along with one of TempelhofPs and two of Hennert's 

 prize dissertations, in a quarto volume, entitled Dis- 

 sertations sur la Theorie des Cmnetes. Utrecht, 1780. 

 Upon the death of D'Alembert in 1783, Condorcet 

 succeeded, in virtue of his former appointment, to the 

 Secretaryship of the Academy of Sciences, and in thi* 

 office he distinguished himself by his Eloges on some 

 of the most celebrated members. His Account of the 

 Life and Discoveries of D'Alembert and Euler ; his 

 Eloge on the celebrated Turgot ; his Life of Voltaire, 

 which appeared in 1787 ; and his Biographical Account 

 of Dr Franklin, which appeared in 1790, display a deep 

 knowledge of science and of character, and exhibit the 

 peculiar talent which Condorcet eminently possessed, 

 of giving a perspicuous and comprehensive view of the 

 labours and discoveries of others. 



Amidst the duties of his new office, Condorcet did not 

 forget his mathematical pursuits. His attention was 

 turned particularly to the doctrine of chances ; and he 

 treated this subject in a series of four memoirs, enti- 

 tled, Sur le Calcul des Probabilites, and printed in the 

 Memoirs of the Academy between 1781 and 1785. 

 He published also a separate work on the subject, enti- 

 tled, Essai sur I'application d'analyse a la Probabilite 

 des Decisions, 4to, 1785. In the application of the re- 

 sults of his investigations to the practical purposes of 

 life, he examined the probability of an assembly's giving 

 a true decision, and he explained the limits to which 

 our knowledge of future events might extend, when 

 regulated by the laws of nature. He supposed that we 

 have, at least, a mean probability that the law indicated 

 by events is constant, and will be perpetually observed. 

 He regarded a forty-five thousandth part as the value 

 of the risk, in the case when the consideration of a new 

 law comes under our notice ; and it results from his 

 formulae, that an assembly consisting of 6l voters, where 

 it is requisite that there should be a plurality of nine, 

 will fulfil this condition, if there is a probability that 

 each vote is equal to five-fifths, that is, if there is a pro- 

 bability that each member shall be deceived only once 

 m five times. These calculations he next applies to 

 p 



