There’s an argument about the consequences of unbelief that many atheists struggle to accept, but which carries some force. Indeed, a friend of mine recently made this argument on the Facebook page of the Richard Dawkins’ Foundation for Science and Reason and got himself summarily deleted and expelled from the group.

The argument is simple: atheism cannot provide a logical warrant for love of all humankind. Here’s how my friend put it in the Dawkins forum:

Atheists don’t believe people are a special or privileged species. In other words, we are no different to slugs. When atheists (like Stalin) treat people like slugs, they are being quite consistent with their philosophy.

Christians do believe people are special and privileged. We are God's “children”, and have inherent value and dignity. When we treat others badly, we are being *inconsistent* with our philosophy.

“Love your neighbor” doesn’t follow logically from atheism. It’s not integral to that philosophy. It does follow logically from Christianity, and is absolutely integral.

If “There is no God,” then “Love your neighbor” is optional.

If “Christ is Lord”, then “Love your neighbor” is fundamental.

I can see how atheists could have taken offence at the connection between atheism and Stalin. But, of course, my friend was not saying all atheists are ‘Stalinesque’ any more than he was implying that all Christians are like Mother Theresa and love their neighbour. His point is entirely about the logical warrant for behaviour. Even if we conceded that, in practice, atheists were better human beings than Christians, that would not change the logical force of the argument at all.

Let’s agree, then, that atheists and Christians are equally capable of love and hate. I know plenty of non-believers who are fine human beings. But now let’s ask about the logical consistence of love/hate within the Christian/atheist perspective. Surely, everyone can agree that when Christians love they do so in full logical accord with a worldview that begins with the notions—whether true or false—of the love of God and the inherent value of His beloved creatures. When Christians hate, therefore, they do so in logical defiance of these fundamental convictions.

Turning to the atheists perspective, we may ask: What is there in the atheist’s viewpoint that can logically inspire love and discourage hate? To say that we have evolved to love is not an answer, for this only tells us that love has survival advantages, not whether love is logical.

Without any notion of a Loving Entity at the root of reality (God) or any way to secure the inalienable worth of homo sapiens in the universe, atheism has no ability logically to ground the call to love all of humanity. That was my friend’s simple point: love is optional on atheistic assumptions and fundamental on Christian assumptions. The point is not whether atheism or Christianity happens to be true.Put another way, whereas only one way of life is rationally compatible with Christianity (the way of love), any kind of life is rationally compatible with atheism.

The fact that my friend got deleted and expelled from an atheism forum for making this case, suggests to me either that the moderators didn’t understand the argument (and dismissed it as a mere insult) or that they did understand it and found it genuinely disturbing.