Before anyone goes off and starts a new thread on the subject of “atheism as a religion”, I’d like to interject, though my interjection, I assure you, is not one likely to inflame the argument, just a suggestion of a possibility.
It is my belief that the category of “religion” is entirely meaningless in this debate. The idea that there are certain beliefs or groups that are categorized as “religious” pr pertaining to a “religion” (I’ll stop using quotes henceforth) is only pertinent for political and perhaps some cultural debates. But with theological, moral, or philosophical issues, the category is meaningless, as it is completely culturally constructed.
I think that most religious people, and I hope that most nonreligious people, can understand that for a person who sincerely believes in, say, Christianity, that the essential tenets of Christianity (God exists, was incarnated in Christ, rose from the dead, etc.) are not religious beliefs; they are simply truths. There is no more reason to call them religious beliefs than to call the beliefs that firearms should be outlawed, that murder is immoral, or even that evolution is a valid theory, religious beliefs. One may counter that, in fact, religious beliefs do have inherent commonalities, like that they all pertain to the nature of a deity. However, for a sincere Christian, pretty much everything they believe, about morality, politics, even philosophy and science, pertain, in some way, to their fundamental worldview, their belief in the truth of Christianity. Most, if not all people, have certain fundamental (what we may call “philosophical”) beliefs that they either believe or presuppose that lay at the core of all other beliefs.
So I would argue that the assertion that certain beliefs are religious is not at all based on observation of the nature of the beliefs. It is merely a sociological phenomenon. Our society has, for historical and cultural reasons, ascribes certain commonly held beliefs to the category of religion, not for any fundamentally logical reasons.
So when one asks, “is atheism a religion?”, the question can only be answered by observing the cultural influence of atheism on those who believe it. I would say that the more a group of atheists share a common identity, and common beliefs outside of their atheism, the more they begin to constitute what could be called a religion, or a philosophy, or a worldview, words which are ultimately really interchangeable. I would note, for example, that literary critic Terry Eagleton, in his criticism of Richard Dawkins, observes that Dawkins is not merely an Atheist, but that he belongs to an “ideology” (another interchangeable): he is not merely a disbeliever in God, he is a western, liberal, humanist, rationalist atheist; and in his book, he shows clear signs of this by assuming a variety of common beliefs: atheists support abortion, atheists support gay rights, atheists support liberal democracy, atheists believe in the existence of morality, and many others.
To be sure, the fact that one does not believe in a deity does not mean that one necessarily belongs to a sociological group called a religion (like secular humanism or atheistic Marxism), just as the fact that one who believes that Christ rose from the dead does not necessarily belong to such a category (Terry Eagleton, I believe, considers himself to be a Christian-Marxist, a contradiction in terms to most “religious” people). There are, I think, atheist religions, and ones that define themselves by their atheism.
We should keep in mind, of course, that the category of religion is a concept invented by human beings, and it is the cultural context of a belief or set of beliefs that determine whether or not is belongs to this category, not some objective philosophical truth.