Screen shot of the 2015 video “Atheist Sin Problem” (Ѻ), by Libb Thims, in query about a non-supernatural solution to the Phil Robertson’s sin problem scenario (stated below), in respect to how do how does an atheist justifiably explain "right" and "wrong" to a murderer-rapist.

“All nature is but art, unknown to thee;
All chance, direction, which thou canst not see;
All discord, harmony not understood;
All partial evil, universal good.
And, spite of pride, in erring reason's spite,
One truth is clear, 'Whatever is, is right'.”

See main: Robertson sin problem

“The ‘sin problem’ is something you can’t solve. [Namely] This ‘conscience’ thing, we just dreamed it up. There’s no right, there’s no wrong, there’s no good, there’s no evil.

I’ll make a bet with you: Two guys break into an atheist’s home. He has a little atheist wife and two little atheist daughters. Two guys break into his home and tie him up in a chair and gag him. And then they take his two daughters in front of him and rape both of them and then shoot them and they take his wife and then decapitate her head off in front of him. And then they can look at him and say, ‘Isn’t it great that I don’t have to worry about being judged? Isn’t it great that there’s nothing wrong with this? There’s no right or wrong, now is it dude?’

Then you take a sharp knife and take his manhood and hold it in front of him and say, ‘Wouldn’t it be something if this [sic] was something wrong with this? But you’re the one who says there is no God, there’s no right, there’s no wrong, so we’re just having fun. We’re sick in the head, have a nice day.’ If it happened to them, they probably would say, ‘something about this just ain’t right.’”

“Right is right even if no one is doing it; wrong is wrong even if everyone is doing it.”

— Augustine (c.420) (Ѻ)

“Whenever morality is based on theology, whenever the right is made dependent on divine authority, the most immoral, unjust, infamous things can be justified and established. Morality is then surrendered to the groundless arbitrariness of religion.”

— Ludwig Feuerbach (c.1860) (Ѻ)

“Some people often think that if you’re an atheist, you don’t believe in god, then you can’t have a morality. There’s no foundation to morality and morality’s in question and so forth. [...] It’s amazing to me that people in the current world still think that way, because that view was refuted 2.5 thousand years ago by Socrates, in the Euthyphro argument (Ѻ), where Socrates made the point that you can’t define goodness or rightness as what god commands, because the reason god commands it is that it’s right, it’s not right because god commands it. [...] So, god cannot be the foundation of morality in that sense.”

— Colin McGinn (2009), “Does Morality Need God?” [2]

“The amoral nurse might reject that he or she has a moral duty to uphold a patient’s rights. The amoral nurse would also probably claim that it does not make any sense even to speak of things like a patient’s ‘rights’ since moral language itself has no meaning. The amoralist’s position in this respect is analogous to the atheist’s rejection of certain religious terms. The extreme atheist, for example, would argue against uttering the word 'god', since it refers to nothing and therefore has no meaning. Such an atheist might also claim that there is no point in engaging in a religious debate on the existence of god, since there is just nothing there to debate. To try and debate the existence of god would be like trying to debate the existence of a ‘black cat in a darkened room when there isn’t one’ [see: Dave Allen, “The Leap of Faith” joke (Ѻ)(Ѻ)] . The amoralist may argue in a similar way in relation to the issue of morality.”

— Megan-Jan Johnston (2011), Bioethics: a Nursing Perspective (Ѻ)