Without God, we are mere biologic machines. One consequence of a Godless existence is that there is no such thing as objective good or evil.   Michael Ruse, an agnostic philosopher of science, observed:

“Morality is a biological adaptation no less than are hands and feet and teeth. Considered as a rationally justifiable set of claims about an objective something, ethics is illusory. Morality is just an aid to survival and reproduction...and any deeper meaning is illusory.”

In Isaiah 5:20, our God said, "Woe to those who call evil good, and good evil; Who substitute darkness for light and light for darkness!" With utter atheism, mankind has gone one logical step further to the final conclusion: that there is no such thing as good or evil; there is only what pleases us or doesn't.