Mathematician, physicist and religious philosopher, b. 19 June 1623 (Clermont-Ferrand, France), d. 19 August 1662 (Paris).
Pascal's father was the presiding judge of the tax court in Clermont-Ferrand. When Blaise was 3 years old his mother died, and the family moved to Paris, where his father looked after the education of his children. He had an interest in mathematics and was respected for his contributions in this field. His two children also proved to be gifted, Blaise's sister in the field of literature and Blaise himself in mathematics, physics and mechanics.
When Blaise's father was appointed to the local administration of Rouen, the 16 year old Blaise started on the design of a calculating machine to assist his father with his tax calculations. The machine, the first digital calculator ever invented, was completed in 1644. During these years the young Pascal also wrote several essays on mathematical topics, which raised the admiration and envy of Descartes.
During the following years Pascal embarked on physical experimentation. He studied the theories of Galileo Galilei and tested the principle of the barometer discovered by Torricelli by measuring air pressure in Paris and on a mountain top near Clermond-Ferrand. He invented the syringe and constructed a hydraulic press, which worked on what has become known as Pascal's Law that pressure in a fluid acts equally in all directions. This work led him to studies of the vacuum and the weight and density of air. He continued his mathematical investigations with the Traité du triangle arithmétique, a treatise on the arithmetic triangle of the binomial coefficients. In his last work he laid the foundations for the calculus of probabilities.
This highly productive period of scientific activity came to an end after 1655, when Pascal's interest in religion caused him to join the convent of Port-Royal. He had already turned to Jansenism, an ascetic form of Catholicism, after a severe illness of his father in 1646.
According to Jansenist teaching salvation is predetermined; it is not achieved by good works but is a gift of divine grace. Antoine Arnauld, a supporter of Jansenism, had attacked the prevelant teaching of the church that frequent communion would allow one to commit repeated sins without repentance. The Catholic church considered Jansenism an aberration, and Arnauld had to defend his ideas in a trial before the faculty of theology in Paris.
From 1655 Pascal did not write any more works except when asked to do so by the Jansenists, and he did not publish them under his own name. His first major work of that period, 18 Lettres écrites par Louis de Montalte à un provincial (better known as "Les Provenciales"), was in defense of Arnauld and contains a strong attack on Jesuit ethics. The work totally ignored the pompous style and rhetoric of the literature of the time and replaced it by simple prose of brilliant clarity. It was the beginning of modern French prose and an immediate success when it appeared in 1657. Its impact on the church was such that 20 years later in 1678 Pope Innocent XI agreed to half of Pascal's criticism.
Pascal's second major work, known as Pensées ("Thoughts"), consists of the major parts of a planned but unfinished Apologie de la religion chrétienne (Apologetics of the Christian religion). Written before 1658, it was prepared for the use of friends who did not share his religious conviction and was only published after his death.
During the years 1657 and 1658 Pascal returned to fame through mathematical works. The convent of Port-Royal had asked him to write down his discoveries in the area of geometry and particularly his work on the cycloid curves. But in 1658 an illness caused him to return to religious introspection. He lived an ascetic life helping the poor and died with much suffering, probably from an ulcer of the stomach.
Pascal ranks clearly among the great mathematicians of all time. It is known that his many gifts caused him discomfort; he would have wished to be able to live a simpler life. But his sense for the concrete and his ability for exact analysis shine through even in his religious works, which make the relationship between God and human beings appear as a problem of geometry. French civilization owes him much gratitude for his clarity of style, which pairs eloquence with precision.
The complete sequence of binomial coefficients, generally known as "Pascal's triangle", was known to Chinese mathematicians, who published it in 1303, 300 years before Pascal. In the European civilization it was first postulated by Newton. Bernoulli provided a proof in 1716.