Consider the following question for a moment:
If the atheist movement succeeds, what should replace religion?
My gut-level response to this is "Nothing." Why must religion be replaced with anything? Isn't reality sufficient? However, I am starting to wonder if I might be wrong about this. Just because I do not personally have a need for anything to replace religion in my life does not mean that others do not have such a need. I am beginning to think that we atheists may have an unpleasant task ahead of us in wrestling with this very question.
I realize that some may be delighted at the prospect of trying to formulate a viable alternative to religion. If this describes you, then more power to you. I am glad that you are eager to take on such a challenge, and I hope you succeed. As for me, this does not hold much appeal. I don't feel any sort of void in my post-religion life that I want to fill with something else. And I'm fully prepared to accept the possibility that I am just an outlier in this regard.
Why do I think the task of finding something to replace religion might be unavoidable? For better or worse, it is undeniable that many religious people experience their religion as meeting several needs they are not sure how to meet through other means. Such people are liable to perceive us as suggesting that they simply walk away from everything they have known and embrace the unknown. How many are really brave enough for this?
Imagine trying to convince a country to stop importing foreign oil without providing a clear alternative. Sure, we could simply give up our cars, our electricity, and the like, but how many are going to embrace that? Imagine trying to convince an alcoholic not to visit the local bar anymore when all his friends are there and he isn't sure what else to do with himself. Without some alternative, why would he listen? Imagine trying to help a parent stop using corporal punishment to discipline her child when it is all she knows and you offer no alternatives. You get the idea.
I'd like to believe that religion is different from all these examples, but I'm not sure that it is. At a minimum, we are going to have to show the religious how we live our lives without gods. This may be enough for some, but I suspect others will need more help.
