Atheism is a tricky philosophy to categorize, because it is really the absence of a particular worldview rather than an affirmative1 worldview. I do happen to have an affirmative worldview involving the power of the scientific method, the beauty of nature, and even the value of engaging in some selective irrationality from time to time as a means of embracing our humanity. But among the spectrum of people who self-identify as "atheists", you would find quite a range of different worldviews, with the only commonality being that they exclude the supernatural in general, and magical sky daddies in particular.
I quite like the way NonStampCollector puts it:
Atheism is my "religion", and Not Collecting Stamps is my "hobby".
(By the way, NonStampCollector's YouTube channel is just about the funniest collection of atheism-related cartoons I have ever seen. If you don't watch any others, at least do yourself the favor of checking out this and this. Awesome.)
Anyway, that sums up pretty well the problem with referring to "atheism" as if it were a single cohesive philosophy, let alone describing it as a "religion". There are an infinite number of potential atheistic worldviews. In many ways, it would be more accurate to refer to "atheist" as an adjective rather than a noun.
Before I start talking about whether there is a better word than "atheist", then, it is worth asking the question: Why the need to label myself in this way in the first place? Well, until fairly recently, I didn't really feel any need to do so. And ideally, I still wouldn't.
But unfortunately, we live in a world where, right now, religions of many stripes are having a powerful negative influence in any number of ways, from human rights abuses in Somalia, to political oppression in Iran, to encouraging ignorance in American schoolchildren and holding back long-overdue civil rights reform. In a perfect world, it wouldn't matter whether or not a person decided to (privately) believe in some harmless myth like Tarot cards or Zeus or Jesus. But in the world we live in, it matters a lot. People are suffering and dying every day because of these irrational beliefs.
To put it another way, I'll stop making a big deal out of my lack of religion when other people's religion stops affecting me. Christopher Hitchens says in god is not Great that he "just wants to be left alone," and I think this is a fair request. When I don't have to worry about my son's mind being polluted with Creationist or homophobic propaganda, when my tax money can go to universal health care instead of financing military operations to hold back sectarian violence in the Middle East, when my parents stop throwing away 10% of their income to LD$, Inc., then I won't make a deal about my atheism. Until then, I think it's important to stand up and say, "No. I reject this."
Does this make me an antitheist? Probably. I don't really object to the term, but I don't adopt it because I am not yet 100% certain that some sort of "memetically-engineered" religion (as Daniel Dennet put it in one of his TED talks) couldn't be a boon to the world. I am definitely opposed to pretty much every religion that exists today -- Zen Buddhism is not particularly objectionable, but then again it's barely a religion -- but I sometimes wonder if a religion of some kind is a necessary evil in certain contexts.
I am currently reading Dreams from My Father, and I am occasionally struck by the positive unifying influence of the black churches that Obama talks about. His conversion story makes a convincing case for religion as a legitimate source of hope for the oppressed, when rationality doesn't really provide any hope.
But then I remember some of the more despicable things in the Bible, and I just cannot justify even tacit approval of a philosophy like that. If the African-American community has truly benefited from the sense of hope and community they find in Christianity -- and I am not even convinced this is the case -- then society must eventually find something else that provides the same sense of hope and community to those who need it. Something that doesn't condone the inerrancy of several thousand year old dogma, and doesn't preach hate and condone violence, and encourage lazy thinking.
So, given that I feel the need to strongly self-identify with my lack of theism, what word to use? My favorite term is "nontheist." For one, I like it because it casts a wide umbrella, encompassing atheists as well as agnostics and apatheists. But I especially like it because of the connotation of abstention. In much the same way that a non-smoker abstains from what they see as a harmful habit, a nontheist abstains from a harmful philosophy.
It also makes it quite clear that there is no specific affirmative philosophy being implied. Theists are fond of saying that "an atheist has faith that there is no God", but of course this is very rarely the case. I think the term "nontheist" is less prone to this mistaken impression. A nontheist is simply one who does not engage in the belief in a supernatural diety. This may include a handful of people who indeed have faith in the lack of a God, it includes people like me who think it is astronomically unlikely for there to be a God given the available evidence, and it especially includes the vast masses of secular individuals who simply don't see the question as particularly relevant.
So if I like this term "nontheist" so much, why do I still self-identify as an "atheist"? Well, as I hinted at in the beginning, it is in order to dispel the taboo. In many circles, "atheist" is a dirty word. I probably interact with a dozen people every day who wouldn't blink if I told them I was a Christian or a Jew or a Hindu, but if I said I was an atheist they'd suddenly have some big issue with me. And that is not right.
It's probably explained much better at The Out Campaign, but anyway, I feel we need to take back this word and make it acceptable.
Call me an atheist, then, and give me the same respect you would give any other human being. That's all I ask.
1 When I say "affirmative" here, I don't mean as in a jolly, happy outlook. Rather, I mean in the sense that it says something about what is as opposed to what is not.