A lot of media attention (e.g. - here) has focused on the new American Religious Identification Survey of American's views on religion, which finds that 15% of Americans now say they have no religious affiliation, up from 8% in 1990.

Lack of religious affiliation doesn't necessarily imply atheism however. When asked whether they believe in God, only 2.3% of ARIS respondents said that "there is no such thing" as God. However, 5.7% said that they are "not sure," and 4.3% said that "there is no way to be sure." These two latter answers might be categorized as agnostic. Unfortunately, ARIS didn't ask this question in 1990, so we do not know whether the proportion of atheists and agnostics has increased since then.

The ARIS survey may underestimate the true prevalence of atheism. Because of widespread societal prejudice against atheists, some survey respondents might be hesitant to admit their atheism, even in an anonymous poll. We know from polls on other issues that survey respondents often hide their true beliefs when these conflict with perceived societal norms. I suspect that at least some of the people who gave agnostic responses are actually atheists.

The same may be true of some of the 12.1% who picked the answer stating that "There is a higher power, but no personal God." Ironically, this vague phrasing might be perfectly compatible with atheism, depending on how it is interpreted. Assuming that the "higher power" you believe in is not omnipotent, omniscient, or completely benevolent (the standard attributes of God as depicted by the major monotheistic religions), even the most convinced atheist could potentially choose this answer. For example, I consider myself an atheist in the sense that I believe that God as defined above almost certainly does not exist. However, I also think it's perfectly possible that there are extraterrestrial "higher powers" who are vastly more powerful than we are. UFO enthusiasts notwithstanding, I certainly don't believe that the existence of such superpowerful ETs has actually been demonstrated. But neither has anyone definitively proven that they don't exist.

UPDATE: Apparently, ARIS actually did give respondents the opportunity to identify themselves as "atheist" or "agnostic" on one of the other questions in the survey. Only 0.7% of respondents picked "atheist" and 0.9% chose "agnostic" (both numbers up slightly from 2001).

This result powerfully illuminates the social stigma attached to identifying as an atheist. More than two-thirds of the 2.3% of respondents who said that "there is no such thing" as God still didn't self-identify as atheist even though that is what they clearly are. Some of these people may simply be confused about the definition of the word "atheist;" but I doubt that is the main reason for the discrepancy between the two questions. Equally interesting, some 10% of respondents gave answers indicating that they are unsure about whether God exists or not, yet only 0.9% call themselves "agnostic." Here, respondent confusion may play a bigger role, since the term "agnostic" is probably less widely known than "atheist."

The New York Times had an interesting article a few days ago, claiming that atheist activism has increased in recent years:

More than ever, America's atheists are linking up and speaking out . . .

They are connecting on the Internet, holding meet-ups in bars, advertising on billboards and buses, volunteering at food pantries and picking up roadside trash, earning atheist groups recognition on adopt-a-highway signs.

They liken their strategy to that of the gay-rights movement, which lifted off when closeted members of a scorned minority decided to go public.

Much of the evidence of increased atheist activism the article gives is anecdotal. The one systematic data point is evidence indicating that there are now many more atheist student groups than there were earlier in the decade. Unfortunately, the article also relies on the 2008 American Religious Identification Survey, which shows a major increase in the percentage of Americans who say that they that are not affiliated with any religion (up to 18% of the US population, compared to 10% in 1990). However, as I explained in this post, not affiliating with any religion is not the same thing as being an atheist. In the same ARIS survey, only 2.3% of respondents say that "there is no such thing as" God and 5.7% that they are "not sure." Thus, it is far from clear that the NY Times article is correct in suggesting that the 18% of Americans who are unaffiliated with any religion constitute a large potential reservoir of support for atheist activism.

Despite these caveats, I would not be surprised if atheist activism really has increased in recent years. Throughout modern history, increases in education and wealth have tended to promote secularization, which in turn increases the proportion of atheists in society (even though not all secularists necessarily deny the existence of God). As the Times suggests, atheist activism has likely increased as a reaction to the activities of the religious right. The rise of radical Islamism has also stimulated atheist activism by lending credence to claims that religious belief leads to violence and oppression. I don't think any of the above actually constitutes evidence for the truth of atheism. The fact that the religious right and radical Islamists are wrong about various issues does not in and of itself prove the nonexistence of God; and obviously, adherents of a variety of secular ideologies also have committed numerous wrongs. However, the rise of the religious right domestically and radical Islamism abroad has probably led atheists to engage in more activism than they would have otherwise.

Finally, as I emphasized in this article, atheist activism is needed to counteract the false but widespread impression that (shared by about 50% of the public), that being an atheist means that you reject all morality and have no values.

On this latter point, the Times is correct to draw an analogy to the gay rights movement. Just as the more effective gay activists have sought (with some success) to persuade the public that being gay is not an immoral perversion that undermines "family values," so atheists must dispel the deeply rooted belief that if you don't believe in God, you necessarily reject all moral values. Increases in education, secularism, and societal tolerance make this a more realistic goal than ever before.