Pascal's Wager
In the seventeenth century the mathematician Blaise Pascal formulated his infamous pragmatic argument for belief in God in Pensées. The argument runs as follows:
If you erroneously believe in God, you lose nothing (assuming that death is the absolute end), whereas if you correctly believe in God, you gain everything (eternal bliss). But if you correctly disbelieve in God, you gain nothing (death ends all), whereas if you erroneously disbelieve in God, you lose everything (eternal damnation).
How should you bet? Regardless of any evidence for or against the existence of God, Pascal argued that failure to accept God's existence risks losing everything with no payoff on any count. The best bet, then, is to accept the existence of God. There have been several objections to the wager: that a person cannot simply will himself to believe something that is evidently false to him; that the wager would apply as much to belief in the wrong God as it would to disbelief in all gods, leaving the the believer in any particular god in the same situation as the atheist or agnostic; that God would not reward belief in him based solely on hedging one's bets; and so on.
-- Keith Augustine