Editing Blaise Pascal (section)

===Probability===
In 1654, prompted by his friend the [[Chevalier de Méré]], Pascal corresponded with [[Pierre de Fermat]] on the subject of gambling problems, and from that collaboration was born the mathematical theory of [[probability]].{{sfn|Devlin|p=24}} The specific problem was that of two players who want to finish a game early and, given the current circumstances of the game, want to [[division of the stakes|divide the stakes fairly]], based on the chance each has of winning the game from that point. From this discussion, the notion of [[expected value]] was introduced.  John Ross writes, "Probability theory and the discoveries following it changed the way we regard uncertainty, risk, decision-making, and an individual's and society's ability to influence the course of future events."<ref>{{cite journal|last1=Ross|first1=John F.|year=2004|title=Pascal's legacy|journal=EMBO Reports|volume=5|issue=Suppl 1|pages=S7–S10|doi=10.1038/sj.embor.7400229|pmc=1299210|pmid=15459727}}</ref> Pascal, in the ''[[Pensées]]'', used a probabilistic argument, [[Pascal's wager]], to justify belief in God and a virtuous life. However, Pascal and Fermat, though doing important early work in probability theory, did not develop the field very far. [[Christiaan Huygens]], learning of the subject from the correspondence of Pascal and Fermat, wrote the first book on the subject. Later figures who continued the development of the theory include [[Abraham de Moivre]] and [[Pierre-Simon Laplace]]. The work done by Fermat and Pascal into the calculus of probabilities laid important groundwork for [[Gottfried Wilhelm Leibniz|Leibniz]]'s formulation of the [[calculus]].<ref>{{cite web|title=The Mathematical Leibniz|url=http://www.math.rutgers.edu/courses/436/Honors02/leibniz.html|access-date=16 August 2009|publisher=Math.rutgers.edu|archive-date=3 February 2017|archive-url=https://web.archive.org/web/20170203084344/http://www.math.rutgers.edu/courses/436/Honors02/leibniz.html|url-status=live}}</ref>