(Clermont-Ferrand, France, 1623-Paris, 1662) Philosopher, physicist and French mathematician. His mother died when he was three years, following which his father moved to Paris with his family (1630). He was a precocious genius whom his father began very soon in geometry and introduced into the circle of Mersenne, the Academy, to which he himself belonged. There, Pascal became acquainted with the ideas of Girard Desargues and in 1640 wrote his essay on conics (Essai pour les coniques), that contained what today is known as the hexagon of Pascal theorem.
The designation of his father as a Commissioner of the real tax was transferred to Rouen, where Pascal developed a new interest in the design and construction of a machine to add; There are still several copies of the model who devised, some of whose principles were then used in the modern mechanical calculators.
Rouen Pascal began also to interested in physics, and in particular by the hydrostatic, and undertook his first experiences on the vacuum; He took part in the controversy surrounding the existence of the horror vacui in nature and conducted important experiments (particularly the Puy de Dôme in 1647) in support of the explanation given to the operation of the barometer by Torricelli.
The disease prompted Pascal to return to Paris in the summer of 1647; doctors advised her distraction and a worldly period which ended with his mystical experience of the November 23, 1654, he started his second conversion (in 1645 had embraced the Jansenism); convinced that the way to God was on Christianity, not philosophy, Blaise Pascal suspended his scientific work almost in full.
A few months before, as witnessed his correspondence with Fermat, had occupied the properties of the arithmetic triangle today call of Pascal and giving the developments of the successive powers of a binomial coefficients; his treatment of the triangle in terms of a «geometry of random» became one of the founders of the mathematical calculation of probabilities.
In 1658, apparently in order to forget about a toothache pain, Pascal developed his study of the Cycloid, which proved an important stimulus in the development of the differential calculus. From 1655 he frequented Port-Royal, where his sister Jacqueline had withdrawn in 1652. It took party in favour of Arnauld, the general of the Jansenists, and anonymously published their provincial.
The success of the letters led him to project an apology of the Christian religion; the deterioration of his health from 1658 thwarted, however, the project, and the scattered notes relating to it were later collected in his famous thoughts (South Pensées the religion, 1669). Although he always rejected the possibility of establishing rational proof of the existence of God, whose infinity considered unreachable for the reason, he admitted however that the latter could prepare the way for faith to combat skepticism. Pascal's famous bet discusses belief in God in terms of bet on its existence, because if the man believes and finally God does not exist, nothing is really lost.
The tension of thought between science and religion was reflected in its admission of two principles of knowledge: reason (l'esprit géométrique), directed towards the scientific truths and systematically proceeding from definitions and hypothesis demonstratively towards new propositions, and the heart (esprit de finesse), not served from systematic procedures because it has a power of immediate understanding sudden and total, in terms of intuition. This last is the source of insight necessary to choose the values that the reason must be based his work.