Prayer is one of the most common phenomena of human life. Even deliberately nonreligious people pray at times. Studies have shown that in secularized countries, prayer continues to be practiced not only by those who have no religious preference but even by many of those who do not believe in God. One 2004 study found that nearly 30 percent of atheists admitted they prayed "sometimes," and another found that 17 percent of nonbelievers in God pray regularly. The frequency of prayer increases with age, even among those who do not return to church or identify with any institutional faith. Italian scholar Giuseppe Giordan summarized: "In virtually all studies of the sociology of religious behavior it is clearly apparent that a very high percentage of people declare they pray every day—and many say even many times a day."

Does this mean that everyone prays? No, it does not. Many atheists are rightly offended by the saying "There are no atheists in foxholes." There are many people who do not pray even in times of extreme danger. Still, though prayer … is a global [reality], inhabiting all cultures and involving the overwhelming majority of people at some point in their lives. Efforts to find cultures, even very remote and isolated ones, without some form of religion and prayer have failed. There has always been some form of attempt to "communicate between human and divine realms." There seems to be a human instinct for prayer. Swiss theologian Karl Barth calls it our "incurable God-sickness."