Blaise Pascal was a genius – he made grounding breaking discoveries and inventions in maths, physics, fluid dynamics, the natural and applied sciences. He had an intense and close relations with his father , a tax collector in Rouen. As a child prodigy his father was to mentor him, and even as a teenager he invented the mechanical calculator. Later on he was to make a significant impact in geometry and his work on probability theory, strongly influenced the development of modern economics and the social sciences. However, when he was 23, in the winter of 1646, his 58-year-old father broke his hip when he slipped and fell on an icy street of Rouen. In the 17th century this was a very serious accident and would often prove fatal. Pascal chose two of the finest doctors in France, who happened to be local to treat his father, which they did successfully over three months. During which time they became close family friends.
Both doctors were Jansenists and became very influential which lead to a sort of "first conversion" of Pascal who began to write on theological subjects in the course of the following year. His father was to die 5 years later and soon after that his sister Jacqueline announced that she would become a postulant in the Jansenist convent of Port-Royal. Pascal was devastated but eventually with a heavy heart was to allow her to leave. This involved him signing over half of the inheritance and meant that he viewed the convent suspiciously at first – claiming it to have a cult like control over his sister.
However all this changed when on 23 November 1654, between 10:30 and 12:30 at night, Pascal seems to have had an intense religious vision. It had such an impact on him that he immediately recorded the experience – opening his notes with the following words "Fire. God of Abraham, God of Isaac, God of Jacob, not of the philosophers and the scholars..." and concluded by quoting Psalm 119:16: "I will not forget thy word. Amen." So important was this he carefully sewed the document into his coat and always transferred it when he changed clothes; it was discovered only by chance after his death. It renewed his belief and religious commitment and soon he was to make a two-week retreat at Port-Royal. He was to become a regular visitor and began writing his Provincial Letters which was effectively a systematic attack on the Jesuits from a Jansenist perspective. They proved to be hugely popular, widely disseminated and very damaging to the Society.