Atheism – the worldview, not the people group – has a problem with evil. (Please notice how I define atheism).
The problem is sometimes called “the naturalistic fallacy,” which states that “you cannot derive an ought from an is.” In ordinary language, that means you cannot go from a description of how things are to a prescription about how things should be. An example may clarify this. Consider this situation:
Tom ate Jerry in a leisurely fashion.
If this describes two humans, we say, “Ok, when someone eats another human, that violates the rule “Eating another human is disturbing and wrong.” And we conclude: this is disgusting behavior.
If this describes a cat eating a mouse, we relate that to the principle “animals may eat other animals to stay alive.” Then we say, “ok, that’s fine for Tom to do.”
But either way, the important point is that we always connect the facts to a moral rule or principle before we evaluate the facts themselves. Without a moral rule to turn to, we have no way of evaluating the facts and circumstances of our lives as right or wrong, as good or evil.
The problem with atheism is it denies that there exist any moral rules. Instead, atheism affirms that all that exists is matter, energy, and space-time. And the problem for atheism is that these elements are not enough to support the existence of morality.
The following thought experiment demonstrates this: Imagine that I gave you the best laboratory in the world, staffed it with the brightest scientists, gave you whatever equipment you wanted, and said, “Now, create morality!”
This would be impossible. No matter how you rearranged the molecules or put the pieces together, you’d never be able to create morality itself from physical stuff.
The very best you could do is, perhaps, create humanoid like beings who happened to think there were moral truths. Now, of course these beings would be misguided, because all that actually exists is matter, energy, and space-time. Something as immaterial, eternally true and transcendent as “love thy neighbor” doesn’t come – and can’t come – from energy fluctuations.
It might very well be in the best interests of these humanoids, just for the sake of their survival, to make some behaviors taboo and others well-rewarded. Perhaps murder and rape would become “against the law” and sanctioned with prison time. Meanwhile, telling the truth and honoring your promises would be highly valued, and a reputation for doing these things would make it easier for certain humanoids to do business deals.
What you have to notice is that all of this “moral discourse” would just be in their heads! There is nothing really wrong with murder or really right about promise-keeping. Instead, it just happens to be the case that those behaviors are viewed as bad or good, respectively, by their humanoid society.
Let’s imagine that, one day, bored in the laboratory, you set up the humanoid society so that murderers find themselves with an extra 10,000 laboratory dollars in their bank accounts. (Imagine a sick version of The Truman Show). This turns out to be enough money to pay for bodyguards, eliminate other genes from the population, and get their own genes passed down in a higher proportion to the next generation far in excess of other humanoids. On it goes for a few generations, and before long, you have a humanoid society that heartily approves of murder, and violently opposes anyone who tries to keep murderers from their deserved wealth and social status. In this world, in most people’s minds, murder has become highly valued, and opposing murder is very taboo.
It isn’t that this humanoid group has regressed to a more barbaric level. All they have done is adjusted to the “moral code” that best enhances their survival. But again, there isn’t anything right or wrong about their morals. All these ideas are is social understandings that happen, for the moment, to enhance survival in their context.
Remember, the laboratory never creates morality. It can’t. It can only create humanoid beings who happen to think there is such a thing as morality.
What’s true of the laboratory is true of us, in the actual world. We have an undeniable perception of morality, but if atheism is true, this universe does not contain any moral truths. It contains only matter, energy and space-time. And the moral truth “love thy neighbor” is definitely not a material object, a kind of energy, or an amount of space-time.
If you want to be a consistent atheist, then every time you go from “here are the facts” to “here is the proper moral rule for evaluating these facts” you should stop yourself. Then remind yourself: these rules are just a social illusion. Then decide for yourself: this situation is good, this is bad, this is blah. Your own decision is as arbitrary as going along with the social norms you happen to inhabit. If you lived in Saudi Arabia as a woman or in feudal Germany as a knight or in ancient China as a peasant laborer, you’d have a completely different take on “right” and “wrong.”
What this means is that there is no way to call evil “evil.” Was Adolf Hitler a moral monster? No, not if you asked his best friends. Was Osama bin Laden an evil terrorist? No, not for some Taliban leaders in Afghanistan. Was Jeffrey Dahmer wicked for raping, murdering, committing necrophilia, or eating the bodies of some 17 men and boys? No, not if you are interested in imitating him.
It is all relative. And – it is all just in your head.
To summarize: under atheism, there are no such things or categories as good or evil. And second, any perception to the contrary is completely illusory and is merely a byproduct of non-moral, socio-biological forces.
So, for an atheist – the person, not the worldview – to persist in thinking there is a substantial moral difference between Jeffrey Dahmer and Mother Teresea is to take another atheistic leap of faith.
My thanks to William Lane Craig for outlining this approach in his books and public debates.