04 July 2007

Pascal's wager


Back when I did the post on Buridan's ass, I was really going to post something on Blaise Pascal (June 19, 1623–August 19, 1662) since it was the 384th anniversary of Pascal's birth. Not that I keep track of these things, it had just been mentioned on TV and jogged my memory a bit. Pascal has his own "philosophical mind game," along the lines of Buridan's ass.

Blaise Pascal is from the old, old school of scientists. The ones that were both schooled in science and in theology. Pascal was a French mathematician, physicist, and religious philosopher. He was a child prodigy who was educated by his father, made important contributions to the construction of mechanical calculators, the study of fluids, and clarified the concepts of pressure and vacuum. As an engineer in my past life, I dealt with "Pascals" (a unit of pressure equivalent to one newton per square meter) on a daily basis, but never really gave much thought to the man behind the units.

Pascal's wager is actually very simple and it's simplicity brings about criticism and atheistic parallels. I don't believe Pascal, who possessed a mind of incredible talent, was using his wager to prove anything, but as a ponderable for those who didn't believe in God. An impetus to start a conversation, not an end in itself.

A description of the wager:

The Wager is described by Pascal in the Pensées this way:

Let us consider the paraphrased translation of Pascal. "God either exists or He doesn't. Based on the testimony, both general revelation (nature) and special revelation (Scriptures/Bible), it is safe to assume that God does in fact exist. It is abundantly fair to conceive, that there is at least 50% chance that the Christian Creator God does in fact exist. Therefore, since we stand to gain eternity, and thus infinity, the wise and safe choice is to live as though God does exist. If we are right, we gain everything, and lose nothing. If we are wrong, we lose nothing and gain nothing. Therefore, based on simple mathematics, only the fool would choose to live a Godless life. Let us see. Since you must choose, let us see which interests you least. You have nothing to lose. Let us estimate these two chances. If you gain, you gain all; if you lose, you lose nothing. Wager, then, without hesitation that He is."

In his Wager, Pascal attempts to provide an analytical process for a person to evaluate options in regarding belief in God. This is often misinterpreted as simply believing in God or not. As Pascal sets it out, the options are two: live as if God exists, or live as if God does not exist. There is no third possibility.

Therefore, we are faced with the following possibilities:

You live as though God exists.
If God exists, you go to heaven: your gain is infinite.
If God does not exist, you gain nothing & lose nothing.
You live as though God does not exist.
If God exists, you go to hell: your loss is infinite.
If God does not exist, you gain nothing & lose nothing.

With these possibilities, and the principles of statistics, Pascal attempted to demonstrate that the only prudent course of action is to live as if God exists. It is a simple application of game theory (to which Pascal had made important contributions).


The irony is, Pascal was a Jansenist. He is also considered the father of probability theory. How he reconciled probability with his predestined Jansenist beliefs...the odds are against us ever understanding.

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