Do you know people who say they are “spiritual but not religious”? This way of describing oneself is more common than it used to be, but its prevalence should not be exaggerated. The vast majority of Americans--approximately 80 percent--describe themselves as both spiritual and religious. Still, a small but growing minority describe themselves as spiritual but not religious.

Three times since 1998, the General Social Survey, a survey of a nationally representative sample of American adults, has asked respondents, “To what extent to you consider yourself a religious person? Are you very religious, moderately religious, slightly religious, or not religious at all?” And: “To what extent do you consider yourself a spiritual person? Are you . . .”

If we define “spiritual but not religious” as people who say that they are at least moderately spiritual but not more than slightly religious, then 9 percent of respondents were spiritual but not religious in 1998, rising to 14 percent in 2008. More younger than older people describe themselves in this way and, as the above graph shows, the increase in “spiritual but not religious” is more pronounced among the young. Today, 18 percent of 18-39 year olds say they are “spiritual but not religious,” compared to only 11 percent a decade ago.

Interestingly, there are more “spiritual but not religious” people today because nonreligious people are more likely to say they are spiritual, not because people are less likely to say they are religious. In 1998, 24 percent of those low on the self-described “religious” scale said they were spiritual; that increased to 35 percent in 2008. A generic, diffuse type of spirituality seems to be on the rise, perhaps also indicated by small but noticeable recent increases in belief in miracles and in life after death.

What does the growth of this “spiritual but not religious” segment of the population mean for organized religion in the United States? If what people mean when they say they are spiritual but not religious is that they are generally concerned with spiritual matters (whatever that means) but they are not interested in organized religion, then this trend indicates a growing minority of the population whose spiritual inclinations do not lead them to become involved in churches, synagogues, or mosques. This kind of generic, diffuse, and unorganized “spirituality” may provide a growing market for certain kinds of religious products, such as self-help books with spiritual themes, but, even if it continues to rise, it is difficult to see it becoming a solid foundation for new kinds of religious institutions or new forms of religious collective action.