Skeptics say that we cannot know whether God exists, and in a sense they are right. The Bible says in Hebrews 11:1 that faith is "the substance of things hoped for, the evidence of things not seen." If the believer knew, there would be no question of faith. Consider this: I don't have faith that my daughter is in the seventh grade; I know my daughter is in the seventh grade. I haven't been to heaven, and so I cannot say that I know there is such a place. But I believe that there is. Faith is a statement of trust in what we do not know for sure.

But is such faith reasonable or is it, as the atheists frequently allege, "blind faith"? This central human conundrum is the subject of Pascal's famous wager. Pascal did not invent the wager. It was offered by the Muslim theologian Abu Hamid al-Ghazzali in his medieval work The Alchemy of Happiness. Pascal was familiar with Ghazzali and probably derived the argument from him. But Pascal gave the wager its current classic expression, and in doing so he places an unavoidable choice before all believers and unbelievers.

Pascal argues in his Pensees that in life we have to gamble. Let's say you are offered a new job that may take your career to new heights. It looks extremely promising, but of course there are risks. There is no way in advance to know how things will turn out. You have to decide if you will go for it. Or you are in love with a woman. You have been dating for a while, yet you cannot be certain what marriage to her is going to be like for the next several decades. You proceed on the basis of what you know, but what you know is, by the nature of the matter, inadequate. Yet you have to make a decision. You cannot keep saying, "I will remain agnostic until I know for sure." If you wait too long, she will marry someone else, or both of you will be dead.

In the same way, Pascal argues that in making our decision about God, we will never understand everything in advance. No amount of rational investigation can produce definitive answers, since what comes after death remains unknown. Therefore we have to examine the options, and we have to make our wager. But what are the alternatives, and how should we weigh the odds? Pascal argues that we have two basic choices, and either way we must consider the risk of being wrong.

If we have faith in God and it turns out that God does not exist, we face a small downside risk: metaphysical error. But if we reject God during our lives, and it turns out God does exist, there is much more serious risk: eternal separation from God. Based on these two possible outcomes, Pascal declares that it is much less risky to have faith in God. In the face of an uncertain outcome, no rational person would refuse to give up something that is finite if there is the possibility of gaining an infinite prize. In fact, under these conditions it is unreasonable not to believe. Pascal writes, "Let us weigh up the gain and loss involved in calling heads that God exists. If you win, you win everything. If you lose, you lose nothing. Do not hesitate, then: wager that He does exist."

The ingenuity of Pascal's argument is that it emphasizes the practical necessity of us making a choice. This necessity is imposed by death. There comes a day when there are no tomorrows, and then we all have to cast our votes for or against the proposition on the ballot. The unavoidability of the decision exposes the sheer stupidity of agnosticism and religious indifference. These are people who refuse to choose when there is no option to abstain. So the refusal to choose becomes a choice--a choice against God.

Pascal also exposes the pose of the atheist who fancies himself as a brave and lonely man facing the abyss. We admire a man who is steadfast in the face of unavoidable adversity. If we knew we were alone in the universe and that death was the end, then there is no alternative but to stand tough in our mortal skins and curse the darkness. But what would we think of a man who stands ready to face a horrible fate that he has a chance to avert? If you are trapped in the den with a hungry lion, and there is a door that may offer a way out, what sane person would refuse to jump through the door? Viewed this way, the atheist position becomes a kind of reckless intransigence, a foolish attempt to gamble with one's soul.

With their trademark venom, atheists typically condemn, although they cannot refute, Pascal's wager. Christopher Hitchens can do no better than to launch an ad hominem attack on Pascal as a "hypocrite" and a "fraud." Attempting condescension, Richard Dawkins proclaims Pascal's argument "distinctly odd." And why? Because "believing is not something you can decide to do as a matter of policy. At least, it is not something I can decide to do as an act of will." Dawkins is right about this, of course, but the real issue is whether he wants to believe and whether he is open to the call of faith.

Pascal writes that there are two kinds of reasonable people in the world: "those who serve God with all their heart because they know Him, and those who seek Him with all their heart because they do not know Him." Pascal recognizes that faith is a gift. We cannot demand it but only ask God to give it to us. In the meantime the best thing to do is to live a good and moral life, and to live as if God did indeed exist.

And pray the prayer of the skeptic, which I get from the philosopher Peter Kreeft. "God, I don't know whether you even exist. I think you may be only a myth. But I'm not certain....So if you do exist, you must be hearing me now. So I hereby declare myself a seeker, a seeker of the truth, whatever and wherever it is. I want to know the truth and live the truth. If you are the truth, please help me." It is the claim of Christianity that all who seek God in this way with earnest and open hearts will find Him.