Pascal’s Wager: An Update

Should you believe in God? For many people, belief is a matter of faith. But let’s say you didn’t grow up with a religion, or you fell away from religion, and now are wondering whether that was the right choice. Is there a way to approach the question with reasoned analysis, as you would any other major decision? A rational way to optimize your costs and benefits?

It might seem a strange question. But Blaise Pascal offered a solution to it almost four hundred years ago, using what scientists now call decision theory. Pascal framed the choice as a wager—one that you must make, by virtue of being alive. It goes like this: God exists, or he doesn’t. Objectively speaking, none of us knows the probability of this binary. What we do know, and can control, is our response to it. Shall we believe and embrace religion? Or shall we assume that God is a lie and live without concern for the hereafter? It’s that last part that matters, according to Pascal. For if God exists, our choice for or against religion will have eternal consequences.

If God exists—and for now let’s assume we’re talking about the Christian God of Pascal—and you become religious, you stand to gain eternal happiness in heaven. If you forgo religion, your earthly life will be much the same as a religious person’s, though perhaps with more carousing. If God does not exist, the decision to believe or disbelieve has no serious implications for your earthly life and none at all for your eternal prospects, which are nonexistent either way.

If you are certain that God is real, the choice is clear: Be religious, not least because you have a soul to consider. But if you are uncertain, this is where probability comes in. Pascal argues that if you assign to God’s existence even the smallest likelihood, the choice about whether to be religious remains clear from a rational perspective. Only one of the four scenarios he described offers an infinite benefit (the eternal joys of heaven); the others offer merely finite pleasures. So, if you want to optimize your outcomes, it is best to choose religion. To borrow a term from decision theory, religious belief gives you the greatest expected value—that is, the probability of a positive outcome multiplied by its potential return. The smallest chance of infinite happiness conditioned on God’s existence beats finite rewards any day.

But if the math is clear, why do many of the most hard-nosed rationalists eschew spirituality? It turns out that there are a few good objections to Pascal’s analysis. For the most committed atheists, the probability that God exists isn’t small; it’s zero. There is no chance of eternal reward. The only happiness is earthly happiness. For other nonbelievers, the question is not so much whether God exists, but which God. Though most faiths have a notion of eternal reward (heaven, nirvana, jannah), there is always the possibility of choosing the wrong religion. Finally, there is this question: Even if God exists, and even if he permits people to worship him through many different faiths, is an instrumental approach to religion an acceptable one?

These are tricky questions, traditionally understood to reveal the inadequacy of Pascal’s argument. Pascal realized that these rebuttals would lose significance if religious belief improved people’s lives in the here and now—if it provided earthly benefits as well as eternal. In his Pensées, he writes of those who become religious:

You will be faithful, humble, grateful, generous, a sincere friend, truthful. . . . I will tell you that you will thereby gain in this life, and that, at each step you take on this road, you will see so great certainty of gain, so much nothingness in what you risk, that you will at last recognise that you have wagered for something certain and infinite for which you have given nothing.

The problem was that this was only his opinion. Over the past decade, however, new findings have emerged that shift the calculus in Pascal’s favor.

On the basis of three studies, published between 2016 and 2018 and involving tens of thousands of people, Harvard epidemiologist Tyler VanderWeele and colleagues have shown that those who practice a faith have a 33-percent lower risk of dying from any cause over long periods of time. They have lower rates of cancer and cardiovascular disease, lower rates of depression, and fewer suicide attempts. They also report higher levels of happiness and meaning in life. One major benefit of VanderWeele’s work is that, unlike many other studies that find a health benefit for religion, it follows people through time as they choose to start or stop engaging with their faith. Thus, it is fairly clear that a change in religious behavior produces the observed changes in well-being, not vice versa. Two of these studies also show that the benefits of religion aren’t merely a byproduct of socializing—another long-standing objection to this type of research—by demonstrating that the benefits are greater for those who practice a religion than for those who find social connection in other ways. The third study shows that even private practices, such as prayer and meditation, offer benefits, especially when it comes to mental health.

What does this mean for Pascal’s wager? Let’s take the atheist objection: If God does not exist, eternal outcomes are off the table, and what’s left is how the practice of faith affects us in this life. What these findings demonstrate is that faith does have an earthly utility. Sure, some might miss the pleasures of libertinism, but those pleasures don’t compensate for the comprehensive well-being described above. Of course, religion might lead to negative outcomes for some, as tragic cases of abuse and institutional failure make clear. But as is the case with vaccines, the harm is relatively infrequent. The majority of people will experience a benefit, so that practicing a faith becomes the clear rational choice.

What about the problem of which religion to choose? If God does exist, better to pick some faith—the one you think has the highest probability of being true—than none at all. The former gives a shot at infinite reward; the latter forecloses it. If God does not exist, choosing the option—religion—that best enhances health and happiness across cultures and faiths makes the most sense.

But is it acceptable to subscribe to a religion in which you don’t believe, or aren’t sure you believe, for the sake of its earthly benefits? Will you still reap the eternal reward? Only God knows! If you’re not sure that God exists, your uncertainty is doubled, as you certainly can’t be sure of what is in his mind (assuming he exists). But you can be sure of the earthly benefits of acting as though you believed, so religion is to that extent a rational choice.

As to whether it can be a good-faith act to adopt a spiritual practice when you doubt its tenets, I would argue that it can. As many traditions point out, sometimes it is through our actions that we gain understanding or belief. As the people said to Moses in the book of Exodus when he was instructing them in faith, “na’aseh v’nishma”: We will do and then we will understand. That change in belief might come from experiencing benefits you didn’t expect, but it also reveals a basic truth about the mind. As much psychological research over the past sixty years has demonstrated, people’s beliefs will change to match their actions. Studies show that the more effort people put into practices prescribed by a group (for instance, rituals or initiation activities), the more they come to embrace and value the group and its beliefs.

So, should you choose religion? Given what we know (and don’t know) about God’s existence and the benefits of spirituality, I’d say there is no rational reason not to. Of course, people aren’t always rational; they don’t always choose the option that decision models say is best. But if you’re a gambler, Pascal’s wager looks more and more like a good bet.

David DeSteno is professor of psychology at Northeastern University.