The Path of LeRoy James
One of the big arguments against atheism is that it doesn't provide moral guidance, and this is true to a certain extent, but it doesn't have to be. We, as a species, have evolved a moral conscience that helps to guide our behavior.
Societies, also, have developed rules to guide our behavior, and as we grow up in these societies we internalize these rules into our conscience causing us to behave according to the rules of our society. I believe that societies have also gone through the process of natural selection such that the societies with the 'best' rules are the ones that are the strongest and last the longest. Here I'm defining 'best' as the sets of rules that help strengthen a society, which is kind of a circular definition, but it's really the only one that matters when speaking in terms of natural selection.
The key thing here is natural selection. The fact that we, and societies, have evolved these characteristics (and natural selection is the mechanism that guided this evolution) means that they must benefit us somehow, so paying attention to our conscience and our societies rules is important. By studying these rules, both explicit and implicit, we can create the moral guidance that atheism currently lacks.
One key point to remember, though, is that Atheism is not a religion, in that it isn't a single belief. It is characterized not by what they believe in, but by what they don't believe in, i.e. a god. This means that different atheists can believe in completely different things. However, I think most atheists do believe in evolution and natural selection, and science in general. So when I talk about 'atheists", these are the ones that I'm talking about.
FWIW, I consider myself to be both an Atheist and a Christian. I'm an atheist because I don't believe in God, but I was raised as a Christian in a predominantly Christian society, so it is Christianity's icons that are most impactful to me, and the teachings of Jesus, at least in terms of the parables and the golden rule, that I have internalized as my own.
Getting back to how natural selection can provide a moral framework, we have to look at how natural selection has caused us to be what we are. This is a feedback process where we look at what we think we are, and then ask ourselves how natural selection may have shaped us this way. Trying to figure out what we are is fraught with error, but taking the additional step of trying to figure out how natural selection may have made us that way gives us some degree of confidence that our ideas about what we are may be correct.
For example, natural selection should select for those individuals who can best pass their genes on to future generations. This will not only be those individuals who are best able to survive long enough to have kids, but for those who also prioritize raising those kids so that they will be likely to survive, have kids, and raise their kids to survive, have kids, etc.. And if you want your kids to be successful, and their kids, etc., you need to give some effort or thought on how to make your society more successful and stable. Or, if that seems unfeasible, you migrate to another society that is more stable, as we are seeing so many people doing these days.
This is a far cry from the selfish, only in it for themselves, stereotype that most people have of atheists. I don't think most atheists are selfish, but maybe they are, and if they are, it could be because of the lack of moral guidance. One characteristic of humans in general is that our instincts are very weak compared our rationalizations, and even if people have an instinct to spend time raising their kids, if they live in a society that values monetary success more than raising your kids well, then that is what people will focus on, and that is why atheists need a moral guidance that they can believe in and that is meaningful for them. This is not to make them better than members of a more formal religion, it is to shore up the one area in which formal religions are superior to atheism.