In the Pensées and other works, Blaise Pascal contributed to an intense debate between the two major religious groups in France at the time. The Jesuits (or Society of Jesus) were a religious order founded a hundred years previously by St. Ignatius Loyola, whose members had become influential leaders in the Catholic world. The Jansenists were a newer religious order based on the teachings of Cornelius Jansen, a Dutch priest and theologian. Advocating a return to the teachings of the early church father St. Augustine, Jansen accused contemporary Catholicism—especially the Jesuits—of deemphasizing the idea of penance and the seriousness of sin in an effort to make the spiritual life easier for ordinary people.

Jansen’s religious movement attracted many followers in French society because of its moral seriousness. However, the Catholic establishment suspected Jansenism of denying free will and affirming predestination—beliefs more typical of Protestant theology, especially Calvinism, and considered heretical by the Catholic Church. The polemical battle between the Jesuits and the Jansenists was a major feature of religious life in France during the 17th century.

Pascal and his family were influenced by the Jansenist movement; his sister Jacqueline became a nun in the order, and Pascal himself lived near the Jansenist monastery at Port Royal after his “Night of Fire.