at the age of eighteen, he
constructed the first arithmetical calculating machine to help his father, who served as a Royal
Tax Commissioner in Rouen. He made attempts to market the new machine but found little success. Also,
at this time, Pascal made serious contributions to the number theory and geometry. However, Blaise overworked himself to
the point that he strained his health and consequently, collapsed in the street.
the Pascal family found religion when two charitable men introduced the family to the writings of Arnauld, a follower of Jansen.
These two men promoted St. Augustine's doctrine of God's unmerited grace and a more contemplative lifestyle. Therefore,
Blaise and his sister Jacqueline traveled to Port Royal, the home base of the religious
movement, where Blaise admired the priests' scientific view of the human soul as a mechanism. However, due to illness, Pascal
returned to Paris in 1647 where he became an aggressive and respected debater of theological and scientific controversies
at the Paris Academy. Pascal devised a defense of Christianity but members of Port Royal discouraged his efforts because the
work shunned faith for reason. In this same year, Pascal began formal experiments to investigate
the existence of a vacuum. This was a controversial topic that originally attracted his attention during a mercury experiment
he conducted with his father several years before. Pascal learned of and repeated Toricelli's experiments with
the barometer and the theory of air pressure. He
found that the pressure of the atmosphere could be estimated as a weight and he confirmed his theory of the cause of
barometrical variations by obtaining readings at different altitudes at the same time. These experiments
involved placing a tube of mercury upside down in a bowl of mercury. His observations and conclusions led
to the publication of Experiences Nouvelles Touchant Le Vide in 1647.
During the time of Aristotle, Aristotle had argued against the atomists that nature detsests a
vacume. This was a view still strongly held in the seventeenth century, even by anti-Aristotelians such as Descartes
and Hobbes. In the Experiences, Pascal explains the reasons why a genuine vacume could and did exist above the mercury
in the barometer. In defending these conclusions against Father Noel, rector of the College de Clermont in Paris, Pascal gave
one of the clearest statements of scientific method in the seventeenth century.
However, once again Blaise overstrained his health in the arguement with Father Noel. Thus, Blaise's
doctor prescribed a routine of horse back riding, tennis, amusement and relaxation. As Blaise enjoyed his leisure time,
Jacqueline, who was badly scarred from small pox, gave up poetry because she wanted to join the sisterhood at Port
Royal. Etienne, nevertheless, refused to give his permission right up to his death in 1651.
In 1650, still suffering from poor health, Pascal
retired temporarily from mathematics. However, in 1653, after an unexpected recovery, he wrote Traité du Triangle
Arithmétique, in which he described a convenient tabular presentation for binomial coefficients. The "arithmetical triangle"
is now called Pascal's triangle.
Pascal's notable contributions to the fields of the
study of fluids (hydrodynamics and hydrostatics) centered around the principles of hydraulic fluids. His inventions include
the hydraulic press (using hydraulic pressure to multiply force) and the syringe. Also, he clarified concepts such as pressure
(for which his name has been given to the SI unit of pressure) and the vacuum.
In 1654, he corresponded with Fermat and of that collaboration
was born the mathematical theory of probabilities, in which he later used a probabilistic argument, Pascal's Wager, to justify
belief in God and a virtuous life.
Following an accident in 1654, Pascal abandoned mathematics and physics for philosophy and theology.
In this new
field, Pascal gained fame for his attack on casuistry, a popular ethical method used by Catholic thinkers in the early modern
period. Pascal criticized casuistry as the mere use of complex reasoning to justify moral negligence. His writings on this subject, a defense of the
Jansenist Antoine Arnauld, appeared in the Lettres provinciales, or "Provincial Letters." This work enraged
King Louis XIV of France who ordered in 1660 that the book be shredded and burnt.
Pascal's most influential theological work, the Pensées, was unfinished by his death, but a version of his
notes for that book appeared in print in 1670, eight years after and it soon became a classic of devotional literature.
Pascal died in Paris on August 19, 1662, when a malignant
tumor in his stomach spread to his brain. He is buried in the St. Étienne-du-Mont cemetery.