Pascal's Wager is a philosophical argument proposed by the mathematician and philosopher Blaise Pascal. It suggests that believing in God is a rational choice, even if the existence of God cannot be proven. Pascal argues that if God exists and one believes, the reward is infinite happiness in the afterlife. If God does not exist, the believer loses little. On the other hand, if one chooses not to believe and God does exist, the consequences could be severe, potentially resulting in eternal punishment. Therefore, Pascal concludes that it is safer to believe in God than to risk the potential loss of eternal happiness.