Comte Antoine Louis Claude Destutt de Tracy, the French philosopher and propounder of the doctrine of Ideology, was born in Paris. Educated at the University of Strasbourg, he entered the army and served later as deputy of the Bourbonnais nobility to the States-General. Despite his noble rank he was a fervent partisan of reform in monarchical government, but by 1792 he had become disgusted with the extremists among the revolutionaries and retired from politics to Auteuil, where he joined the celebrated group of philosopher-scientists that found its center at the home of Madame Helvétius. Among his intimates were Pierre-Jean-Georges Cabanis and Marquis de Condorcet, Comte de Volney and Dominique Joseph Garat. Imprisoned for a year under the Terror, he began to study the works of Étienne Bonnot de Condillac and John Locke, the result...