You question (re % declared vs % actual) is a fundamental one and I suspect people like Zuckerman and others have addressed it.

I haven't seen the methodology myself, but I would make an educated guess that in gathering data for most of the questions about religious beliefs, in western countries, the responses are anonymous (i.e., person cannot be identified with their responses) and perceived as such by the participants. Such factors are likely to be taken into account in any such research, in western countries, at least as far back as the 1950s. Anonymity reduces the social desirability effect on responses. There still might be some degree of stigma effect in anonymously classifying oneself an atheist, i.e., an internalized stigma. There may also be plain ignorance--many people are de facto atheists but do not realize that they fit the atheist category better than other categories.*

*(For example, in my own case, I had been a non-believer from the age of about 11 or 12, but was not explicitly aware that I had been an "atheist" until about 20 years later, when I actually looked up the definitions for atheist, and compared them with those for agnostic, deist, pantheist, etc.).

We've seen this prediction before, though. Throughout the 20th Century various people made predictions such as these and yet, here we are in 2006, and these predictions are still being made.

I agree that setting specific dates for the end of religion is a fool's errand. (I don't expect it to happen in my lifetime, though it will be intriguing to see how much more progress nonbelievers will make.) But I don't think those earlier predictions were wrong, just a little premature. I'm confident that it will happen eventually.

Unfortunately, what we lack is a good set of survey data showing the percentage of the non-religious in, say, Ingersoll's time, or at the country's founding. That would help calibrate our predictions by giving a good sense of whether the absolute percentage of nonbelievers has been rising and falling over time, or whether it's been steadily growing all this time and it's just the greater or lesser degrees of organization among them in various historical eras, and therefore the presence or absence of an effective opposition to fundamentalism, that produces the appearance of tides of faith washing in and out.

For Ian:

I think you hit the nail on the head there. I'm sure that only a small fraction of that 14% would actually describe themselves as atheists.... Furthermore, you also have to take account of all the new-age and non-denominational beliefs that so often take the place of formal religion for many people, as well.

While only a small fraction of that 14% would describe themselves as atheists - no doubt because of all the slanderous stereotypes that have been attached to the word - the open question is how many actually are atheists, in either a philosophical or a practical sense. I would point out that the 2001 ARIS survey included New Age and non-denominational Christian as specific options (percentage breakdown of the findings is here), so I do think it's reasonable to assume that most of the people who answered as non-religious do not consider themselves as belonging to either of those two groups. For this reason I'm confident that, if perhaps not a majority, then at the very least a significant plurality of the people identifying as non-religious would agree that they were atheists if the religious stereotypes around that word were cleared away.

For SpeirM:

Many of these people don't live their lives as though they were religious. If they tell you they're religious, it's because they think that's what they're supposed to say.

Indeed. :)

For Shishberg:

Just to play devil's advocate (or god's advocate) for a second… is it possible that the number of people who are willing to say that they're nonreligious is increasing, rather than the number of people who actually are nonreligious?

That's quite possible. But even if that's the case, it's still a very good thing - it means that the nonreligious are becoming increasingly willing to speak out, and it implies that there may be even more waiting in the closet, if we can persuade them to step out as well.

I also wonder if their 100 AC complexes are all tax-free in that they are supposedly "churches"? It's always unpleasant to see churches suckling off the teat of public services when contributing nothing to support them.

In the light of evidence such as this, stories about the rise of megachurches can be appreciated in context. The rise of these institutions is not due to growth of Christianity itself; it may simply be a symptom of the greater polarization of our society. As the tide turns against them, more fundamentalist believers are retrenching, joining together in larger churches to isolate themselves from the outside world, but their numbers are not growing. If anything, their absolute numbers are actually decreasing.

In other words, they're getting desperate? ^.^

How much do you suppose a complex like that 100 acre thing costs, to build and per year?

Question: has atheism become significantly more or less of a stigma in the last ten years in the US? I get the impression that it's always been more serious than it is here in Australia, but I'm not sure which direction it's moving, especially after 2001.

http://www.adherents.com/Religions_By_Adherents.html

Top 50 Countries With Highest Proportion of Atheists / Agnostics
(Zuckerman, 2005)
http://www.adherents.com/largecom/com_atheist.html

Secular/Nonreligious/Agnostic/Atheist 1.1 billion
http://www.adherents.com/Religions_By_Adherents.html#Nonreligious

"Pitzer College sociologist Phil Zuckerman compiled country-by-country survey, polling and census numbers relating to atheism, agnosticism, disbelief in God and people who state they are non-religious or have no religious preference. These data were published in the chapter titled "Atheism: Contemporary Rates and Patterns" in The Cambridge Companion to Atheism, ed. by Michael Martin, Cambridge University Press: Cambridge, UK (2005). Different type of data collection methodologies using different types of questions showed a consistent pattern: In most countries only a tiny number of people (zero to a fraction of 1 percent) will answer "atheism" or "atheist" when asked an open-ended question about what their religious preference. A slightly larger number of people will answer "yes" if asked pointedly if they are an atheist. A slightly larger number than that will answer "no" when asked if they believe in any type of God, deities, or Higher Power. A slightly larger number answer "no" when asked simply if they "believe in God" (omitting wording indicating more nebulous, less anthropomorphic conceptions of divinity). Finally, a larger number of people answer "none" or "non-religious" when asked asked an open-ended queston about what their religious preference is. Although figures vary for each country, average numbers indicate that roughly half of the people who self-identify as "nonreligious" also answer "yes" when asked if they believe in God or a Higher Power."

Some Canadian and Canadian vs U.S. stats:

28% (of Canadians) following other religions or no religion

Religion data from the 2001 Canadian census
http://www.religioustolerance.org/can_rel0.htm

Religion: U.S. compared with Canada
http://www.religioustolerance.org/canus_rel.htm

For one thing, there is still the important question of how many of the 14% of citizens that profess no religion are actually atheists, as opposed to how many are theists who belong to no organized church.

I think you hit the nail on the head there. I'm sure that only a small fraction of that 14% would actually describe themselves as atheists. More importantly, most people who have no organized religion are probably no more rational than their religious contemporaries; it's more likely to be indifference or never having been indoctrinated into a specific belief system that puts them in that 14%. Furthermore, you also have to take account of all the new-age and non-denominational beliefs that so often take the place of formal religion for many people, as well.

So whilst I'd love to think that people are becoming more rational in their thinking, you are going to have to show me more evidence first, I'm afraid.

We've seen this prediction before, though. Throughout the 20th Century various people made predictions such as these and yet, here we are in 2006, and these predictions are still being made.

To add to your analogy of faith as battering waves, I think that this sea of faith and religiocity has tides. In the 50's we had the Red scare and such events as adding 'under God' to the Pledge of alligience; in the 60's and early 70's the tide receeded with the backlash against the 50's and later against Vietnam; yet since Roe v Wade the tide has been rising once again. Has it now begun to receed? Possibly, given the numbers you've shown. However, I think its very premature to think we are going to see the day when "those dark waters draw back entirely." Those very words could possibly have been spoken in 1906, yet here we are. I take these numbers with a grain of salt: I see them simply as the tide receeding. Unfortunatly, I'll belive the "rock of reason" has arrived when I see it.