Probability and expectation in Pascal's Pensées

Abstract

The article examines the interaction of scientific ideas and literary works of Blaise Pascal (1623-1662), French mathematician, physicist, writer and Christian philosopher. His mathematical ideas influenced his most famous theological work - the Pensées (Thoughts) which is considered to be a masterpiece and a landmark in French prose. In the Pensées, Pascal analyzes several philosophical paradoxes: infinity and nothing, faith and reason, soul and matter, death and life. In this article I shall start by looking at the geometrical origin of Pascal's most famous comparison of man with "a thinking reed". Then I will examine the connection between two different works: De l'Esprit géométrique and the Pensées. This analysis will bring me to the next point − the mathematical resolution of Pascal's Wager. Historically, Pascal's Wager, where the notion of expected value was introduced, was groundbreaking because it charted new territory in probability theory, marked the first formal use of decision theory, and anticipated future philosophies such as existentialism. Finally, the article presents two mathematical poems from the Pascal's treatises. In the conclusion, it is said that Pascal in his geometrical works explains as a philosopher and in his Thoughts demonstrates as a mathematician, using probability and expectation in mathematical calculation and in existentialist explanation.