It may be impossible to observe the human condition objectively, as humans, but it's worth trying. That being said, it's pretty obvious that there is an innate desire in humans to have a spiritual identity and there are as many versions as there are cultures. Therefore, while we can only speculate about the existence of super nature, the human desire to explain our existence and our awareness of it is not up for debate.
To call yourself "atheist" does not explain anything and is, in fact, just a way of living with a consciousness that does not value magical explanations for things. That being said, taking the position that super nature does not exist is presumptuous, though not nearly as much so as pretending a very specific magic is our reality. We all exist in a state of ignorance about the "grand scheme", so calling yourself an "atheist" is just another form of spiritual division, as much so as calling yourself "catholic" or "muslim".
So, as atheists, for us to pat ourselves on the back for being more honest than the faithful is to celebrate our difference rather than to intelligently acknowledge our similarities. If we atheists are actually endowed with a superior intellect or, at the least, liberated from irrational fears, then we owe it to humanity NOT to play the sectarian game by telling everyone else that we are superior for what we doubt, rather than what we believe. In other words, it behooves us to establish our morality by NOT defining ourselves according to our differences. If we believe that humans all evolved with the same needs and base desires, then we cannot so easily separate ourselves, even from the most dedicated faithful.
So, I have come to identify less as an atheist, which is a subjective interpretation of the spiritual reality of others, and more of an "evolutionist", meaning that I desire the future of humanity to be our focus, rather than the past. If we can come together enough to create a positive self-directed human evolution, then the most harmful spiritual relics of cavemen will finally be vanquished and made powerless to destroy the lives of our offspring the way faith has destroyed so many lives throughout history.
Now, I realize that the word "evolve" is a loaded one within the spiritual community. It is considered a counter argument to creation rather than a process for it. So, a few concessions could be made by both the faithful and faithless to make the future brighter. First of all, having the right to believe whatever you like does not make your beliefs, whatever they are, intelligent. Secondly, a stagnant morality is humanly impossible, so quit trying to pretend it exists. There are NO commandments from the distant past that have any moral relevance today. Religions ALL evolve and denying it makes you seem married to dogma rather than righteousness. And finally, we must all realize that if our philosophy manifests as harm on this planet, it doesn't matter what benefit to the harmed or to ones self that one imagines it creates, it's harm. Stop it!
Boiled down, these rules could be:
1) Don't be an idiot.
2) Don't be afraid to change.
3) Don't be a dick.
If these three common sense "commandments" could be consistently realized by the faithful and faithless alike, our religious labels would seem much less important.