INTRODUCTION

In July of 1654 Blaise Pascal wrote to Pierre Fermat about a gambling problem which came to be known as the Problem of Points: Two players are interrupted in the midst of a game of chance, with the score uneven at that point. How should the stake be divided? The ensuing correspondence between the two French mathematicians counts as the founding document in mathematical probability, even though it was not the first attempt to treat games of chance mathematically (Pascal, [1654] 1970, vol. 1, pp. 33–7; Cardano, [comp. c. 1525] 1966). Some years later, Pascal included among his Pensées an imaginary wager designed to convert sporting libertines: no matter how small we make the odds of God's existence, the pay-off is infinite; infinite bliss for the saved and infinite misery for the damned. Under such conditions, Pascal argued that rational self-interest dictates that we sacrifice our certain but merely finite worldly pleasures to the uncertain but infinite prospect of salvation (Pascal, [1669] 1962, pp. 187–90).