Pascal's Decision

Pascal put together his thoughts about life and religion while he was at Port-Royal and published them under the title Pensées.

In the course of his work on that book, he filled two pieces of paper on both sides with what Ian Hacking describes as “handwriting going in all directions…full of erasures, corrections and seemingly afterthoughts.”

This fragment has come to be known as Pascal’s Wager (le pari de Pascal), which asks “God is or he is not. Which way should we incline? Reason cannot answer.” At the moment, a coin is tossed. Which way would you bet? Heads (God is) or tails (God is not)? Hacking asserts that Pascal’s line of analysis to answer this question is the beginning of the theory of decision making. “Decision Theory,” as Hacking describes it, “is a theory of deciding what to do when it is uncertain what will happen.” Making that decision is the essential first step in any effort to manage risk.

Sometimes we make decisions on the basis of past experiences, out of experiments we or others have conducted in the course of our lifetime. But we cannot conduct experiments that will prove either the existence or the absence of God. Our only alternative is to explore the future consequences of believing in God or rejecting God. Nor can we avert the issue, for by the mere act of living we are forced to play this game.

Pascal explained that belief in God is not a decision. You cannot awaken one morning and declare, “Today I think I will decide to believe in God.” You believe or you do not believe. The decision, therefore, is whether to choose to act in a manner that will lead to believing in God, like living with pious people and following a life of ‘holy water and sacraments.’ The person who follows these precepts is wagering that God is. The person who cannot be bothered with that kind of thing is wagering that God is not.

The only way to choose between a bet that God exists and a bet that there is no God down that infinite distance of Pascal’s coin-tossing game is to decide whether an outcome in which God exists is preferable, more valuable in some sense than an outcome in which God does not exist, even though the probability may be only 50-50. This insight is what conducts Pascal down the path to a decision–a choice in which the value of the outcome and the likelihood that it may occur will differ because the consequences of the two outcomes are different.

If God is not, whether you lead your life piously or sinfully is immaterial. But suppose that God is. Then if you bet against the existence of God by refusing to live a life of piety and sacraments you run the risk of eternal damnation; the winner of the bet that God exists has the possibility of salvation. As salvation is clearly preferable to eternal damnation, the correct decision is to act on the basis that God is. Which is the way we should incline? The answer was obvious to Pascal.

Courtesy: Against the Gods: The Remarkable Story of Risk by Peter L. Bernstein