Blaise Pascal (1623–1662) was a French philosopher and mathematician. His most profound philosophical work, Pensées, remained incomplete at the time of his death.
The best known portion of Pascal's religious philosophy is Pascal's Wager, his justification for belief in God. Pascal recognized the apparent impossibility of determining whether or not God exists. Instead, each person must decide whether to believe in God, or not to (as either atheist or agnostic). Pascal guessed that the expected benefits of believing in God outweighed the benefits of not believing, and made the decision to believe.
In Christianity, as in many similar religions, belief in God comes with various rewards, including the entrance to heaven. Denial of God's existence, however, can be met with punishment.
Pascal explains that if one chooses to believe in God, and God does exist, then those rewards become available. If, however, one chooses not to believe in God, and God does exist, then that person may be subjected to misery. In either case, if God does not exist, the status quo remains and nothing is really lost.
Since it's impossible to be certain of the existence of God, Pascal suggests that belief in him is the "safer" bet.
Several opponents of this theory discuss the moral issues of choosing to wager for God in this manner. (In essence, following Pascal's Wager is a selfish act and is devoid of any real spiritual journey.) Pascal's Wager only suggests, though, that reason requires you to wager for God, not that one should wager one's beliefs.
Other critics of the philosophy point out a few flaws in this approach. For example, there may be many gods, or there may be one God, but that God is of a different religion (so your wager for God may be for the wrong God). Atheists also suggest that reason can disprove the existence of God, and for that reason the probability of God's existence is 0, and the wager is meaningless.
Name: Blasie Pascal
Born: June 19, 1623
Died: August 19, 1662