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Why did Voltaire quarrel with Jean-Jacques Rousseau?

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Life-sized plaster sculpture Seated Voltaire by Jean-Antoine Houdon shows Voltaire draped in a robe, seated with a thoughtful expression and a ribbon crown, against a dark background. — Voltaire *Voltaire*, plaster sculpture by Jean-Antoine Houdon; in the Los Angeles County Museum of Art, California.

The quarrel between Voltaire and Jean-Jacques Rousseau was rooted in their fundamental philosophical disagreements and specific cultural conflicts in Geneva.12

The tension escalated in 1757 following the publication of the seventh volume of the Encyclopédie. At Voltaire’s instigation, his fellow philosopher Jean d’Alembert wrote an article on Geneva that praised certain pastors for their doubts regarding Christ’s divinity and suggested the city should build a theatre.12

Rousseau, who valued Calvinist orthodoxy and viewed the theatre as a corrupting influence on an innocent community, responded with a polemical treatise titled Lettre à d’Alembert sur les spectacles (1758). This defense of traditional values and attack on the rationalist philosophy of the philosophes marked a final break between the two writers. While Voltaire championed reason, progress, and satire, Rousseau increasingly emphasized sentiment, passion, and a critique of the corrupting effects of civilization, leading to a deep ideological divide.1234