Three cheers for atheist campaigner Ariane Sherine. For Ariane – who was behind the controversial "There's Probably No God" adverts a while back – is launching a new initiative which we Christians can support.

Her latest endeavour has an aim which is easy to comprehend – if harder to achieve: it's to make the world a kinder place.

Writing in The Guardian a few days ago, Ariane described how it all began when she looked at her two-year-old daughter one night and thought: "I only hope I can teach you to be kind."

And now she has written a book called "Give: How to be Happy" which you can download for free (since, to be consistent, she's giving it away) from www.givebook.co.uk.

But what, we might ask, does it mean to be kind? As an atheist, Ariane says she looked to her friends – including a blood donor, a medical test volunteer and a charity worker – for inspiration. The book which resulted from this sets out ten things people can do, and encourages us to adopt one of them – be it giving blood regularly, or always voting in an election.

Well, it seems to me that as Christians we can say a hearty "Amen" to Ariane – or perhaps, to be more sensitive to her atheistic sensibilities, just give a heartfelt thumbs up.

But there are also some problems. For starters, Ariane herself states that the book is full of swearing and lewd jokes – and I have changed the actual words she used to describe the jokes in order to make it acceptable on a Christian website. So, we might ask ourselves: how kind, in fact, is that?

On the other hand, as I write that last paragraph, I realise that Ariane is seeking to promote kindness in a high-profile way – while I am just penning an article about it. So in criticising her book in this way I am perhaps being somewhat unkind myself and indeed hypocritical. Or, as Jesus puts it, how can we say, "Let me take the speck out of your eye," to someone – when all the time there is a plank in our own.

But referring to Jesus perhaps brings us to a more substantive issue. For the first problem with an atheistic notion of kindness is that it is a human and hence variable construct. It lacks any absolute touchstone (such as Jesus) against which to evaluate it.

And that's an issue because, as Timothy Keller writes in The Reason for God, ethics without reference to God is both unsustainable in practice – and not in fact how most people live. He says: "Though we have been taught that all moral values are relative to individuals and cultures, we can't live like that. In actual practice we inevitably treat some principles as absolute standards... The Nazis who exterminated Jews may have claimed that they didn't feel it was immoral at all. [But] we don't care. We don't care if they sincerely felt they were doing a service to humanity. They ought not to have done it."

Finally, perhaps the most difficult problem about Ariane's atheistic notion of kindness is that, although it makes her happier, it does not deal with the underlying issue – our human hearts. As Jesus says: "Out of the heart come evil thoughts – murder, adultery, sexual immorality, theft, false testimony, slander."

Ariane is to be applauded for promoting kindness; she is undoubtedly a better person than I am for doing so. She is also, perhaps, as Jesus might say, "not far from the kingdom". So let's pray that having embraced kindness she one day discovers where it comes from – and Who.