**Blaise Pascal** – (June19 , 1623 – August 19 , 1662) was a French mathematician, physicist and philosopher with contributions to numerous fields of science as well as to the construction of mechanical calculators , to the probability theory and to the study of the fluids by clarifying the concepts of pressure and vacuum. Following to a religious revelation, in1654 Pascal abandons the mathematics and the exact sciences and dedicates his life to the philosophy and religion.

In the honour of his contribution to the science his name was given to the measure unit of pressure, as well as to a programming language .

Pascal was born in Clermont , (now Clermont-Ferrand) on Juin 19, 1623 in the region of Auverne of France. He was the Etienne Pascal’s third child and his single son. Blaise’s mother died when he was at the age of only 3 , the little child Blaise being very touched by his mother’s loosing . In 1632 Etienne and his four children leaved Clermont and established in Paris and being a mathematician with un-ortodox views on the education he decided that Blaise not to learn anything about mathematics up to the age of 15. On the age of 12, being stimulated by this interdiction, Blaise started to learn geometry on his own finding that” the sum of the angles of a triangle is equal to 2 right angles”. When Blaise’s father heard about this fact he released the previous interdiction and allowed to Blaise to have a copy of Euclid’s „Elements “.

In December 1639, the Pascal family leaved Paris for living in Rouen where Etienne was appointed Collector of taxes for Upper Normandie and where Blaise publishes in February 1640 Essay on Conic Sections . After working for three years between 1642 and 1645, Pascal invented the first machanical calculator, Pascaline, for helping his father in the work as the Collector of taxes.

In 1646 his father’s leg was wounded and he had to recover at home being cured by two younger brothers of a religious movement who exerted a great influence on the young Pascal who became profoundly religious. Also in this period there were the first attempts of studies on the atmospheric pressure and in 1647 he demonstrates that the vacuum exists after he contradicted with Descartes on this scientific truth on September 25 of that year. In 1648 Pascal noted that the atmospheric pressure decreased with altitude and concluded that above the atmosphere there is vacuum.

In September 1651, Etienne Pascal died. In a letter addresed to one of his sisters Blaise awards a deep Christian sense to the death in general and to the death of his father in particular and these ideas were the base of his later philosophical work – Les pensées.

Since May 1653, Pascal writes Récit de la grande expérience de l’équilibre des liqueurs (Treaty about the equilibrium of liquids) in which he explains the Law of pressure. After the correspondence with Fermat in the summer of 1654 he laid the bases for the Probability Theory. On this period he also have health problems but continues the work up to October 1654. On November 23, 1654, after a religious experience he dedicates his life to Christendom. After this date Pascal pays visits to the Port-Royal des Champs Jansenists Monastery situated at 30 km south–west of Paris and in 1656 publishes anonimous works joined in Lettres provinciales. Between 1656 and 1658 he writes Les pensées, the most known theologic work of Pascal.

Died on 19 August 1662 (aged 39) after the proliferation of the malignant tumor of stomak and was buried at St. Étienne-du-Mont in Paris.

Contribuions to the science

At the age of 16, Pascal presented his original result known as Pascal’s triangle (Pascal theoreme), and at 18 he achieved the first mechanical calculator for helping his father to calculate the taxes. The device which was named Pascaline, was like the mechanical calculator of 1840’ years and this invention makes Pascal as the second person who invented tha calculator because Schickard had invented another one in 1624. Pascal is confronted by problems of calculator design due to the French system of that time . There were 20 sols in a livre and 12 deniers in a sol such that Pascal had to resolve technical problems much more dificult due to dividing the livre by 240 instead of deviding by 100. In any way, the manufacture of the apparatus started in 1642 but up to 1652 it had been made 50 prototypes from which only a few were sold and the manufacture of the Pascal’s arithmetic calculator stopped in that year. One of these prototypes there is now in Zwinger museum in Dresden, Germany.

Hearing about the attempt of Torricelli to determine the atmospheric pressure, Pascal started to search various types of tests which to demonstrate the truth of Toricelli’s discovery, building an installation with tubes which demonstrated the influence of pressure. In August 1468 Pascal observed that the atmospheric pressure decreases with altitude and concluded that above the atmosphere there is vaccuum. Descartes wrote to Carcavi in June 1647 about Pascal’s tests : „It is me who advised him two years ago to do this and, for this reason, although I myself did not participate in, I had no doubt of our success …“, although a year before after a dispute with Pascal concerning the existence of vaccuum he had written to Huygens that Pascal „… had too much vaccuum in his head .“

Pascal was the first who realised that by menas of the barometer the difference of altitude between two points can be measured and drew the attention that the modiffication of the mercury column length depends also on the humidity and on the air temperature and this fact can be used for meteorological forecasts. No less important are Pascal works in the field of hydrostatics. In his most important work „Treaty about the equilibrium of liquids“ he formulated the fundamental law of Hydrostatics, named later The Pascal’s Law. He calculated the hydrostatic pressure , described the hydrostatic paradox, the law of communicating vessels and the principle of the hydraulic press.

From the correspondences with Fermat there will arise the probability theory as an answer to questions asked by the chevalier de Mére concerning dice.

Since 1654 he abandons the scientific world for dedicating to Christendom and his last published work is that which describes the curve traced by a point in the circumference of a circle which rolls. Since 1658 he begins again to think about the problems of mathematics because of the pains which tortured his sleeping. Pascal challenged Wren, Laloubère, Leibniz, Huygens, Wallis, Fermat by two problems : the calculation of the area of any cycloid segment and the gravity center of any segment, problems which were solved by Pascal using the indivisibles calculation of Cavalieri in the letters to Carcavi.

Contributions to the Philosophy and the Theology

Pascal dealt also with the Philosophy considering that the scientific progress is the purpose of the humanity existence. Oscilating between the rationalism and skepticism and being influenced in the childhood by the faith in God, he choose the faith towards the end of his life. Blaise Pascal participated together with his father in the conventions of the abbot Mersenne belonging to the Order of Minims since the age of 14 and after his father leg is wounded and is cured by two brothers of a religious Order he became profoundly religious. After an accident he suffered in 1654 on the bridge of Neuilly on Seine and especially after a religious revelation which he had in November 23 ,1654 Pascal decided to take the way of Faith by visiting the jansenits Monastery near Paris.

The most known philosophy work of Pascal is Les pensées, which is a collection of thoughts on the human sufference and on trusting in God and a Christian apologetic work addressed to the dessacralised world . This work comprises also the Pascal’s famous wager which tries to demonstrate that God exists, using a theory of probability. Beginning with the correspondence with Fermat to demonstrate a problem of dice, Pascal presumes that all the cases appear „equally easy” for that Somebody, The Supreme takes care to such a distribution , His wager was : „if God exists and I am a Catholic, I gain the eternal life submitting to the church ; if not I have nothing to loose” . In a few words Pascal’s conception was: God exists because it is the best wager and Pascal needed God existence to mend from time to time the disorder in the Universe.

Pascal made theological speculations on the notion of infinit while Isaac Newton, Leibnitz (and just he himself in his studies on the epicycloid), laid the bases of the infinitesimal calculus from which later by leaving the mystic aura it will arise The Mathematical Analysis .