Atheist Michael Shermer, in his new book The Science of Good and Evil: Why People Cheat, Gossip, Share, Care, and Follow the Golden Rule, writes: "Can we lead moral lives without recourse to a transcendent being that may or may not exist? Can we construct an ethical system without religion? Most believers and theists answer no."
Shermer's comments are misleading. First, I am not sure that most believers and theists answer no. Maybe. Maybe not. However, the likes of William Lane Craig et. al. answer yes. Of course persons can be good without believing in God. The deeper response is this: without God, there is no reason to be good. Thus Nietzsche says, in the absence of God, we must move "beyond good and evil."
In the midst of his comments Shermer cites Dostoevsky's famous quote from The Brothers Karamozov: "If God does not exist, then anything goes." Dostoevsky's idea speaks to the deeper issue. Which is: of course people can be good without God. But without God, there is no real reason to be good. Thus, without God, anything goes.
Can we be moral beings? Yes. Can we construct moral systems? Yes. Should we be moral beings? If there is no God-as-Moral-Originator, the answer seems to be: no.