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Blaise Pascal
Blaise Pascal
(Engraving, 17th Century)

Blaise Pascal (1623 - 1662) was a French philosopher, mathematician and scientist of the Age of Reason.

His earliest (and best known) work was as a mathematician of the first order, especially in the areas of projective geometry and probability theory, and he made important contributions to the natural and applied sciences and wrote in defence of the scientific method. He is also regarded as one of the most important authors of the French Classical Period and one of the greatest masters of French prose.

After a mystical experience late in his short life, however, he devoted himself to philosophy and theology. He opposed both the Rationalism of René Descartes and the main countervailing philosophy, British Empiricist, as being insufficient for determining major truths.


Pascal was born on 19 June 1623 in Clermont-Ferrand in central France. His father was Étienne Pascal, a local judge and aristocrat, who also had an interest in science and mathematics; his mother was Antoinette Bégon, who died when Pascal was just three years old. He had two sisters, the younger Jacqueline and the elder Gilberte. In 1631, his father sold his legal position (a common practice in that time) and invested the money in a government bond which provided a comfortable (if not a lavish) income, and which allowed the family to move to Paris. There, they hired Louise Delfault as a maid, and she eventually became an instrumental member of the family (although his father never remarried).

Pascal's father decided to educate his children himself, for they all showed extraordinary intellectual ability, particularly his son Blaise who was clearly something of a child prodigy. He taught his son grammar, Latin, Spanish, and mathematics, all according to an original method. The young Pascal showed an amazing aptitude for mathematics and science, composing a treatise on the sounds of vibrating bodies at age eleven, and an independent proof of the sum of the angles of a triangle at twelve.

The boy was then allowed to study Euclid, and to sit in (as a silent on-looker) at the gatherings at the monastic cell of Père Marin Mersenne (1588 - 1648), where some of the greatest mathematicians and scientists in Europe (including Gilles de Roberval, Gérard Desargues, Claude Mydorge, Pierre Gassendi and René Descartes) often met. As a result of this, the precocious sixteen year old Pascal submitted to the group a treatise on the geometry of cones, which included what has come to be known as Pascal's Theorem.

In 1638, however, Cardinal Richelieu defaulted on the government's bonds (in order to fund his war efforts), and the Pascal family found themselves in much reduced circumstances. His father was eventually forced to flee Paris because of his opposition to Richelieu's fiscal policies, and the children were left for a while in the care of their neighbour Madame Sainctot (a great beauty with an infamous past, who kept one of the most glittering and intellectual salons in all France). By the following year, however, Pascals' father had been restored to the Cardinal's good graces, and even appointed as the king's commissioner of taxes in the city of Rouen.

From as early as his eighteenth year, Pascal suffered from a nervous ailment that left him hardly a day without pain. Nevertheless, throughout the 1640s and early 1650s, Pascal produced some of his most famous mathematical work (including what have become known as Pascal's Calculator and Pascal's Triangle, and work on the theory of probabilities and the calculus of probabilities), and scientific work (particularly in the fields of hydrodynamics and hydrostatics, and including the inventions of the hydraulic press, the syringe, and a much improved barometer).

In 1647, a paralytic attack so disabled him that he moved to Paris with his sister Jacqueline in search of better medical treatment. His health improved a little, but his nervous system had been permanently damaged and he was subject to deepening hypochondria and fits of anger and depression.

Around this time, he also became interested in the teachings of a Catholic splinter group known as Jansenism, which was becoming popular in France at the time, and he began to write on theological subjects for the first time in the course of 1647, although this initial religious engagement soon faded. His father died in 1651, leaving his inheritance to Pascal and Jacqueline, who then left to become a postulant in the Jansenist convent of Port-Royal.

In November 1654, he had a brush with death after a carriage accident, from which he emerged unscathed but the shock of which apparently led to an intense religious vision which revitalized his belief and religious commitment. He started regularly visiting the convents at Port-Royal for retreats and began writing his first major literary work on religion, the "Lettres provinciales" ("Provincial Letters"). His religion was reinforced by an apparent miracle at Port-Royal, and he set his mind to write his final, unfinished testament (and most influential theological work), the "Pensées" ("Thoughts"), now widely considered to be his masterpiece and a landmark in French prose.

In his latter years in Paris, he followed an ascetic lifestyle and, in 1659, Pascal, whose health had never been good, fell seriously ill, rejecting the ministrations of his doctors in the belief that "sickness is the natural state of Christians". King Louis XIV suppressed the Jansenist movement in 1661, and his sister Jacqueline died the same year, leading Pascal to relax his religious fervour somewhat. In 1662, Pascal's illness became more violent, and he eventually died after suffering convulsions on 19 August 1662, just 39 years old.

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Pascals's philosophical and theological writing began only late in life, after his mystical religious vision of 1654. His first major literary work on religion, the "Lettres provinciales" ("Provincial Letters"), was published between 1656 and 1657 under a pseudonym. It attacked the casuistry (case-based, as opposed to principle-based, reasoning) of many Catholic thinkers in the early modern period (especially the Jesuits) as the mere use of complex reasoning to justify moral laxity and all sorts of sins. It provoked and incensed both King Louis XIV (who ordered the books shredded and burnt), and Pope Alexander VII (who condemned them, despite being persuaded by Pascal's arguments). However, the "Provincial Letters" were extremely popular as a literary work, and influenced the prose of later French writers like Voltaire and Jean-Jacques Rousseau.

Pascal's most influential theological work, referred to posthumously as the "Pensées" ("Thoughts") although originally entitled "Apologie de la religion Chrétienne" ("Defence of the Christian Religion"), was not completed before his death. On its first publication in 1670 (albeit expurgated for the times) it instantly became a classic, and is widely considered Pascals' masterpiece as well as a landmark in French prose. It was to have been a sustained and coherent examination and defence of the Christian faith, although it never quite lived up to that. One of its (high risk) main strategies was to use the contradictory philosophies of Skepticism and Stoicism (exemplified by Michel de Montaigne and Epictetus respectively) in order to bring the unbeliever to such despair and confusion that he would embrace God. It confirmed Pascal's position as a Fideist (the view that religious belief depends on faith or revelation, rather than reason, intellect or natural theology.

Pascal's best kown foray into the Philosophy of Religion was his argument for belief in God, which has become known as Pascal’s Wager. It is based not on an appeal to evidence that God exists, but rather that it is in our interests to believe in God and it is therefore rational for us to do so. He argued as follows: If we believe in God, then if he exists we will receive an infinite reward in heaven, while if he does not then we have lost little or nothing. Conversely, if we do not believe in God, then if he exists we will receive an infinite punishment in hell, while if he does not then we will have gained little or nothing. Thus, "either receiving an infinite reward in heaven or losing little or nothing" is clearly preferable to "either receiving an infinite punishment in hell or gaining little or nothing", so it is rational to believe in God, even if there is no evidence that he exists.

As a young man, Pascal had already proved himself a mathematician of the first order, writing his first mathematical treatises as young as 11 or 12 years old. In 1642 (then not yet nineteen), he constructed a mechanical calculator capable of addition and subtraction, known as Pascal's Calculator (or the Pascaline), the first and most basic of around fifty he built over the course of his life. In 1653, he completed another mathematical milestone, his "Traité du triangle arithmétique" ("Treatise on the Arithmetical Triangle") in which he described a convenient tabular presentation for binomial coefficients, now called Pascal's Triangle. In 1654, he corresponded with Pierre de Fermat (1601 - 1665) on the new mathematical theory of probabilities, and their work on the calculus of probabilities laid important groundwork for Gottfried Leibniz's later formulation of the infinitesimal calculus.

In the late 1640s and early 1650s, Pascal pursued the study of hydrodynamics and hydrostatics, and clarified the concepts of pressure and vacuum (the possibility of which had been denied since Aristotelian times) by generalizing the early work of Evangelista Torricelli (1608 - 1647) on barometers, which he first encountered in 1646. His inventions include the hydraulic press (using hydraulic pressure to multiply force) and the syringe.

He also gave one of the 17th Century's major statements on the scientific method: "In order to show that a hypothesis is evident, it does not suffice that all the phenomena follow from it; instead, if it leads to something contrary to a single one of the phenomena, that suffices to establish its falsity".

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