How did Jansenism influence Blaise Pascal’s religious thought?

Jansenism, a 17th-century movement rooted in Augustinian theology, profoundly shaped Blaise Pascal’s religious life and intellectual output. After encountering Jansenist disciples in 1646, Pascal adopted their austere moral and theological framework, which emphasized the corruption of human nature by original sin and the absolute necessity of divine grace for salvation.1

This influence is most evident in his major works:

• Les Provinciales: Written to defend the Jansenist Antoine Arnauld, these letters attacked the Jesuits for their perceived "relaxed morality" and their emphasis on human responsibility over divine initiative, which Jansenists viewed as a relapse into Pelagianism.23
• Pensées: Pascal’s unfinished apologetics reflect the Jansenist conviction that humanity is a mixture of greatness and wretchedness, explicable only through the Fall. He argued that individuals must be brought to God through Jesus Christ alone, rejecting any compromise between worldly philosophy and the demands of the gospel.34

Ultimately, Jansenism provided the spiritual foundation for Pascal’s turn away from the world toward an ascetic, devotional life centered on the soul's union with God.14