Atheism advocates rationality.
Rationalising our thoughts and actions to create a form of morality that will lead to a better society.

They claim, that we dont need the standards of religion to know how to act right.
But that by using our brains, reasoning things through we will be on the right track.

Under the rule of rationalisation, the question then becomes , "What constitute evil?":
The atheist viewpoint is that anything that doesnt harm the next person or those we interact
with is okay.
This sweeps many actions that would be regarded as immoral/sin in other religions into the good light.
e.g
homosexxuality will be okay.
consensual adultery -
etc

But this approach will still fail.
The nature of man in society proves this.
Violence, debauchery, greed,selfishness, sadism, pride runs through the very nature of society.
Pervesion is inherent in society.

Nobel prize winners and very educated men commit grim felonies before our eyes.
People awash with all the money they need still dissapoint in their actions.
Violence is a issue in society too. The underbelly of society is brutal.
What of oppression- employer employee oppressions.
Clearly, the rationalising our actions to produce better behaviour fails.
Some people , know fully well ,what is wrong but still want to do it.
They love having an evil streak.
They're not decieved.

Of course, the bible's viewpoint is different.

[color=#000099][/color]How amusing... so, either by hook or by crook, religion must be the foundation of morality, and it always manages to go all the way back to Christianity? But, have you really read the Bible before making this ill-informed assertion? You want that book to be the final arbiter on what is moral and what is not? Are you for real?