Voltaire sometimes doubted Jean Le Rond d’Alembert’s zeal for the cause of Enlightenment, and d’Alembert’s distancing himself from the encyclopédistes reveals that he was not one to take great risks. He observed that “honest men can no longer fight except by hiding behind the hedges, but from that position they can fire some good shots at the wild beasts infesting the country.” From his post in the salons and the Académie Française, he worked, as he told Voltaire, “to gain esteem for the little flock” of philosophes.
If Voltaire could accuse d’Alembert of excessive caution, d’Alembert could in turn charge Voltaire with toadying to the powerful. In his 1753 Essai sur les gens de lettres, d’Alembert urged writers to rely solely on their talents, and he reminded the nobility that intellectuals were their equals. “I am determined never to put myself in the service of anyone and to die as free as I have lived,” he wrote Voltaire. Neither Frederick the Great’s repeated invitations to assume the presidency of the Berlin Academy nor Catherine the Great’s offer of 100,000 livres a year to tutor her son Grand Duke Paul could lure him away from France and independence.
In both his life and thought he was loyal to the ideals of the philosophes, so it is fitting that Ernst Cassirer should choose him as the representative of the Enlightenment and call him “one of the most important scholars of the age and one of its intellectual spokesmen.” His belief in the ability of reason to solve any problem epitomizes the view of eighteenth century intellectuals, but he also recognized the role of experimentation and imagination. In his Eléméns de musique théorique et practique suivant les principes de M. Rameau (1752), d’Alembert dissented from Jean-Philippe Rameau’s view that one can devise mathematical rules for composition. As in his article on elocution in the Encyclopédie, he argued that rules are necessary, but only genius can elevate a work beyond mediocrity. Excellent scientist though he was, he ranked the artist above the philosopher.