Pascal, Blaise (1623-1662)

French philosopher, mathematician, and physicist, considered one of the great minds in Western intellectual history. Pascal was born in Clermont-Ferrand on June 19, 1623, and his family settled in Paris in 1629. Under the tutelage of his father, Pascal soon proved himself a mathematical prodigy, and at the age of 16 he formulated one of the basic theorems of projective geometry, known as Pascal's theorem and described in his Essai pour les coniques (Essay on Conics, 1639). In 1642 he invented the first mechanical adding machine. Pascal proved by experimentation in 1648 that the level of the mercury column in a barometer is determined by an increase or decrease in the surrounding atmospheric pressure rather than by a vacuum, as previously believed. This discovery verified the hypothesis of the Italian physicist Evangelista Torricelli concerning the effect of atmospheric pressure on the equilibrium of liquids. Six years later, in conjunction with the French mathematician Pierre de Fermat, Pascal formulated the mathematical theory of probability, which has become important in such fields as actuarial, mathematical, and social statistics and as a fundamental element in the calculations of modern theoretical physics. Pascal's other important scientific contributions include the derivation of Pascal's law or principle, which states that fluids transmit pressures equally in all directions, and his investigations in the geometry of infinitesimals. His methodology reflected his emphasis on empirical experimentation as opposed to analytical, a priori methods, and he believed that human progress is perpetuated by the accumulation of scientific discoveries resulting from such experimentation.  Later Life and Works   Pascal espoused Jansenism and in 1654 entered the Jansenist community at Port Royal, where he led a rigorously ascetic life until his death eight years later. In 1656 he wrote the famous 18 Lettres provinciales (Provincial Letters), in which he attacked the Jesuits for their attempts to reconcile 16th-century naturalism with orthodox Roman Catholicism. His most positive religious statement appeared posthumously (he died August 19, 1662); it was published in fragmentary form in 1670 as Apologie de la religion Chrétienne (Apology of the Christian Religion). In these fragments, which later were incorporated into his major work, he posed the alternatives of potential salvation and eternal damnation, with the implication that only by conversion to Jansenism could salvation be achieved. Pascal asserted that whether or not salvation was achieved, humanity's ultimate destiny is an afterlife belonging to a supernatural realm that can only be known intuitively. Pascal's final important work was Pensées sur la religion et sur quelques autres sujets (Thoughts on Religion and on Other Subjects), also published in 1670. In the Pensées Pascal attempted to explain and justify the difficulties of human life by the doctrine of original sin, and he contended that revelation can be comprehended only by faith, which in turn is justified by revelation. Pascal's writings urging acceptance of the Christian life contain frequent applications of the calculations of probability; he reasoned that the value of eternal happiness is infinite and that although the probability of gaining such happiness by religion may be small it is infinitely greater than by any other course of human conduct or belief. A reclassification of the Pensées, a careful work begun in 1935 and continued by several scholars, does not reconstruct the Apologie, but allows the reader to follow the plan that Pascal himself would have followed.  Evaluation   Pascal was one of the most eminent mathematicians and physicists of his day and one of the greatest mystical writers in Christian literature. His religious works are personal in their speculation on matters beyond human understanding. He is generally ranked among the finest French polemicists, especially in the Lettres provinciales, a classic in the literature of irony. Pascal's prose style is noted for its originality and, in particular, for its total lack of artifice. He affects his readers by his use of logic and the passionate force of his dialectic.