That was a portion of the title of an atheist book. The obvious question becomes, if you CAN be good without God, then why aren’t you?
Of course, from a Christian perspective, from an eternal perspective, the question is not one of goodness but of being forgiven. Nevertheless, the most recent example that atheists can't be good is 10's of thousands of them drawing pictures of Mohammed, on the ground no less on Draw Mo Day.
Now, I’m no fan of Islam, it’s about on par with atheism for the value it holds for humans. On the other hand, to deliberately provoke a couple billion people by placing their most revered symbol, ON THE GROUND, which in their belief system is the greatest affront possible is a long, long way from good.
The fact is, atheists don’t even live up to their own moral standards. They find themselves telling “big” lies when they told themselves that only “little” lies were ok. They find themselves flat out fantasising about someone else’s spouse when they’d told themselves only a little lust was fine.
In order to see themselves as good, atheists move the goal posts and "Ta Da! I'm a good person."
The definition of whatever behaviour or thought they can’t say no to, is simply changed from bad to good. Porn is good, lust is good, objectifying women while jerking off is good. "Since that stuff is no longer wrong, I'm now a good person."
A second step in order to see themselves as good is either to flat out lie to themselves or “comparing down.” Atheists compare down to those who do worse things than they do. This is of course just a different form of lying to self. Yet this is the standard for those who say they don’t need God in order to be good. "See, I'm not as bad as he is, therefore I'm a good person."
One of the things that appealed to me most about Christianity was that it completely does away with this delusion of goodness. “No one is good. All have sinned and fall short of God’s standard for us."
Atheists, as a group, as no worse than anyone else. But neither are they any better. Their belief that they are morally and intellectually superior to others is proof that they cannot be good, with or without God.