Before the "Discourse" was ever created, d'Alembert was actually better known for his scientific and mathematical genius. However, over time, and in part due to his vibrant personality, he befriended Madame du Deffand, whose powerful salon ultimately allowed him to enter the public eye as a philosophe. d'Alembert also became a close ally of Diderot, and eventually, d'Alembert was a man who was held in very high regard among Europe's intellectuals. Ultimately, d'Alembert's tendency to turn more to history to explain the foundations of science and ethics reflects a general historical trend to seek enlightenment and better understanding of human nature in history. Ultimately, the Discourse defines two ways of approaching ideas, one of which being operations of the "isolated mind" (xli) and the other concerning studies of the origins of truth as a function of the progress of a given society. Although the Discourse derives much of its fundamental principles from men such as René Descartes, John Locke and Condillac in a purely metaphysical sense, the effect of historical experience is vital.