He was the French advocate of the symbolic logic that emerged in the years before World War I, thanks to the writings of Charles Sanders Peirce, Giuseppe Peano and his school, and especially to The Principles of Mathematics by Couturat's friend and correspondent Bertrand Russell. Like Russell, Couturat saw symbolic logic as a tool to advance both mathematics and the philosophy of mathematics. In this, he was opposed by Henri Poincaré, who took considerable exception to Couturat's efforts to interest the French in symbolic logic. With the benefit of hindsight, we can see that Couturat was in broad agreement with the logicism of Russell, while Poincaré anticipated Brouwer's intuitionism. His first major publication was Couturat. In 1901, he published La Logique de Leibniz, a detailed study of Leibniz the logician, based on his examination of the huge Leibniz Nachlass in Hanover. Even though Leibniz had died in 1716, his Nachlass was cataloged only in 1895. Only then was it possible to determine the extent of Leibniz's unpublished work on logic. In 1903, Couturat published much of that work in another large volume, his Opuscules et Fragments Inedits de Leibniz, containing many of the documents he had examined while writing La Loqique. Couturat was thus the first to appreciate that Leibniz was the greatest logician during the more than 2000 years that separate Aristotle from George Boole and Augustus De Morgan. A significant part of the 20th century Leibniz revival is grounded in Couturat's editorial and exegetical efforts. This work on Leibniz attracted Russell, also the author of a 1900 book on Leibniz, and thus began their professional correspondence and friendship. In 1905, Couturat published a work on logic and the foundations of mathematics which was originally conceived as a translation of Russell's Principles of Mathematics. In the same year, he published L'Algèbre de la logique, a classic introduction to Boolean algebra and the works of C.S. Peirce and Ernst Schröder. In 1907, Couturat helped found the constructed languageIdo, an offshoot of Esperanto, and was Ido's principal advocate over the remainder of his life. By advocating a constructed international language, constructed along logical principles and with a vocabulary taken from existing European languages, Couturat was paralleling Peano's advocacy of Interlingua. By pushing Ido, Couturat walked in Leibniz's footsteps; Leibniz called for the creation a universal symbolic and conceptual language he named the characteristica universalis. Couturat, a confirmed pacifist, was killed when his car was hit by a car carrying orders for the mobilization of the French Army, in the first stage of World War I. He appears as a character in Joseph Skibell's 2010 novel, A Curable Romantic.
Works
1896: Thesim Facultati Litterarum Parisiensi proponebat Ludovicus Couturat, Scholae Normalae olim alumnus. Parisiis: Felix Alcan Bibliopola. 120 p.
1896: '. Republished 1975, Georg Olms.
1901: '. Republished 1961, Georg Olms.
1903: Opuscules et Fragments Inédits de Leibniz. Republished 1966, Georg Olms.
