"There's a law of diminishing returns on preaching". So said author Kate Grenville in a thought provoking lecture, 'Writers in a Time of Change', in 2009*. Yet everyday, in thousands of blog posts and columns all over the world, preaching is exactly what many very earnest writers do. I do it myself - often. There is lots that's wrong in our world and writers, particularly non-fiction writers, feel obliged to point these things out.

Serious points, we believe, require serious treatment. The better writing avoids the rant. It constructs argument with a frame of well researched numbers. It adds colour with a carefully chosen analogy or anecdote - perhaps even sprinkling of humour. It might provide a more interesting read by the editing out of cliché. But no matter which approaches are used, all this intense writing ultimately relies on the rationality of the audience for its point to be made.

And here's the rub: rationality, as any observer of the climate change argument will tell you, doesn't tend to get us very far. It might reinforce existing views - on both sides of the argument - but it has  limited ability to smash through those views and profoundly change a perspective.

Grenville's argument was that fiction writers, along with artists, have at their disposal a much more powerful tool for doing this: emotion. She quoted Kafka: "A book is an axe for the frozen sea within us". Art, she said, has the ability to flip the switch over to some new kind of thinking.

Up in the Air, the already much lauded new film by Jason Reitman (Juno, Thank You for Smoking) illustrates Grenville's point beautifully.

I have written often of our screwed up priorities when it comes to work. You know the drill: "We only get one chance at this." "No one ever died wishing they had worked more." "It's relationships, not possessions, that give us happiness." All that stuff.

But I have never made these points with the emotional connection or entertainment value of Up in the Air. The film is at once hilariously funny and piercingly insightful. Its characters, perfectly cast, are as real as any you will see on screen. Everyone who has worked in an office has worked with a young upstart like Natalie (Anna Kendrick, of Twilight fame). We've all listened to (and some of us have been) the smooth conference presenter/mile high wanker of Ryan Bingham (George Clooney - a heartthrob who can actually act). Alex (Vera Famiga) is perhaps a bit unrealistically easy-going early on, but she redeems herself by turning out to be two-faced in the end.

Whatreally makes Up in the Air so memorable, in the end, isn't the underlying messages. They are hardly original. And it certainly isn't cinematic fireworks - no CGI or 3D here, thanks. No, it's essential strength comes from a good story really well told.

To quote Grenville again: "The most powerful art comes from somewhere other than a conscious desire to persuade". Through a great story, rather than direct persuasion, Reitman surreptitiously opens our minds to the real way many of us live our lives. He forces us to question why we labour as we do and whether we give our relationships the dedication they deserve.

As an added benefit, he also has us confront one of the great delusions of our time: the ludicrous status attached to a gold card and entry to an 'exclusive' airport lounge.

Before seeing Up in the Air I was wondering how so much fuss could be made about a film based on a bloke who sacks people for a living. Now I know, and the fuss is well justified.

*An edited version of the lecture is available in Edition 26 of The Griffith Review. It can be read online here.