The Lettres provinciales (Provincial letters) are a series of eighteen letters written by French philosopher and theologian Blaise Pascal under the pseudonym Louis de Montalte. Written in the midst of the formulary controversy between the Jansenists and the Jesuits, they are a defense of the Jansenist Antoine Arnauld from Port-Royal-des-Champs, a friend of Pascal who in 1656 was condemned by the Facult de Thologie at the Sorbonne in Paris for views that were claimed to be heretical. The first letter is dated January 23, 1656 and the eighteenth March 24, 1657. A fragmentary nineteenth letter is frequently included with the other eighteen.

In these letters, Pascal humorously attacked casuistry, a rhetorical method often used by Jesuit theologians, and accused Jesuits of moral laxity. Being quickly forced underground while writing the Provincial Letters, Pascal pretended they were reports from a Parisian to a friend in the provinces, on the moral and theological issues then exciting the intellectual and religious circles in the capital. In the letters, Pascal's tone combines the fervor of a convert with the wit and polish of a man of the world. Their style meant that, quite apart from their religious influence, the Provincial Letters were popular as a literary work. Adding to that popularity was Pascal's use of humor, mockery, and satire in his arguments. The letters also influenced the prose of later French writers like Voltaire and Jean-Jacques Rousseau. Brilliantly written by Pascal, the Provincial Letters would not have been possible without the work of theologians from Port-Royal; indeed, most of the arguments Pascal deployed were already to be found in Arnauld's Thologie morale des Jsuites, something which led the Jesuit Nicolas Caussin to reply to Pascal's perceived libel. Pascal's main source on Jesuit casuistry was Antonio Escobar's Summula casuum conscientiae (1627), several propositions of which would be later condemned by Pope Innocent XI.

Paradoxically, the Provincial Letters were both a success and a defeat: a defeat, on the political and theological level, and a success on the moral level. The final letter from Pascal, in 1657, had defied the Pope himself, provoking Alexander VII to condemn the letters. But that didn't stop most of educated France from reading them. Moreover, even Pope Alexander, while publicly opposing them, nonetheless was persuaded by Pascal's arguments. Just a few years later (166566, and then 1679), Alexander condemned "laxity" in the church and ordered a revision of casuistic texts.



Blaise Pascal ( pass-KAL, also UK: -⁠KAHL, PASS-kəl, -⁠kal, US: pahs-KAHL; French: [blɛz paskal]; 19 June 1623 – 19 August 1662) was a French mathematician, physicist, inventor, philosopher, writer, and Catholic theologian.

He was a child prodigy who was educated by his father, a tax collector in Rouen. Pascal's earliest mathematical work was on conic sections; he wrote a significant treatise on the subject of projective geometry at the age of 16. He later corresponded with Pierre de Fermat on probability theory, strongly influencing the development of modern economics and social science. In 1642, while still a teenager, he started some pioneering work on calculating machines (called Pascal's calculators and later Pascalines), establishing him as one of the first two inventors of the mechanical calculator.Like his contemporary Rene Descartes, Pascal was also a pioneer in the natural and applied sciences. Pascal wrote in defense of the scientific method and produced several controversial results. He made important contributions to the study of fluids, and clarified the concepts of pressure and vacuum by generalising the work of Evangelista Torricelli. Following Torricelli and Galileo Galilei, he rebutted the likes of Aristotle and Descartes who insisted that nature abhors a vacuum in 1647.

In 1646, he and his sister Jacqueline identified with the religious movement within Catholicism known by its detractors as Jansenism. Following a religious experience in late 1654, he began writing influential works on philosophy and theology. His two most famous works date from this period: the Lettres provinciales and the Pensées, the former set in the conflict between Jansenists and Jesuits. The latter contains Pascal's Wager, known in the original as the Discourse on the Machine, a fideistic probabilistic argument for God's existence. In that year, he also wrote an important treatise on the arithmetical triangle. Between 1658 and 1659, he wrote on the cycloid and its use in calculating the volume of solids.

Throughout his life, Pascal was in frail health, especially after the age of 18; he died just two months after his 39th birthday.