Blaise Pascal, answered from the texts and cited to the page.
The pari is not a probabilistic argument for God's existence — reason, I say explicitly, "can decide nothing on the issue." God is not an empirical hypothesis of however great or small a probability. The argument is practical: we are already embarqués — committed by the structure of our lives to one side or the other — and those who decline to choose have in practice chosen against.
Given an infinite prize against a finite stake, the asymmetry of the stakes alone makes it rational to wager on God.1 The advice that follows — take holy water, go to mass — rests on the theory of the automaton: habit shapes the will, and the will is the organ of belief, not the intellect.2 Mechanical piety, pursued honestly, can reshape the coeur from the outside in.34
But there is here an infinity of an infinitely happy life to gain, a chance of gain against a finite number of chances of loss, and what you stake is finite. It is all divided; wherever the infinite is and there is not an infinity of chances of loss against that of gain, there is no time to hesitate, you must give all.Pensées
Learn of those who have been bound like you, and who now stake all their possessions. These are people who know the way which you would follow, and who are cured of an ill of which you would be cured. Follow the way by which they began; by acting as if they believed, taking the holy water, having masses said, etc.Pensées
But we do not know what it is. It is false that it is even, it is false that it is odd; for the addition of a unit can make no change in its nature. Yet it is a number, and every number is odd or even (this is certainly true of every finite number). So we may well know that there is a God without knowing what He is. Is there not one substantial truth, seeing there are so many things which are not the truth itself?Pensées
What will you wager? According to reason, you can do neither the one thing nor the other; according to reason, you can defend neither of the propositions. Do not then reprove for error those who have made a choice; for you know nothing about it.Pensées
Voltaire read the Wager as an attempt to prove God's existence by reason, and condemned it as "indecent and childish." The misreading is instructive: I said the opposite at every turn. James's "Will to Believe" (1897) captures something of the practical thrust, though his liberal empiricism does not share the Augustinian anthropology that gives the advice its teeth. Hájek's 2003 critique identifies genuine mathematical complications in the expectation-value structure; these concern the formalization, not the underlying argument — finite stakes are worthless against an infinite prize, and the framing does not require a well-defined probability space.