There’s a certain kind of book that I tend to purchase at airports. It’s one that I think I could finish during the flight (and if I don’t like it, abandon it somewhere to lighten my luggage), and one that will also deliver to me something ‘nuggetty’ and useful, a piece of insight or information that I might not pause long enough to notice during a less airborne day.

These ambitions mean it’s the only time I’m likely to grab something from the ‘personal development’ shelf. The psychoanalysts can tell me what that means (I’m told it’s something to do with ‘in between spaces’).

On a recent city hop, I picked up The Change Book, by Mikael Krogerus and Roman Tschäppeler, a compact hardback full of pithy two-page chapters on how humans cope with change, in particular the different decision-making models we use. Among intriguing chapters (“When Something Starts to Be Uncool”, “Why Parents Are Unimportant”, “Who Rules the World”) I stumbled across an unexpected subject: “How Jesus Would Invest”.

This little chapter contrasts Western capitalism with Islamic banking, drawing on the work of Paul Mills, an economist at the University of Cambridge.

In summary, Islamic banking provides a banking sector based on religious laws: no speculation; no products related to alcohol, prostitution or pork; no charging interest. This last prohibition makes for a profoundly different relationship between investors and banks. But it is the ethical framework that drew the attention of the authors.

They ask the question whether the West could ever establish a banking sector based on ethical principles and, prompted by Mills, suggest that the answer is yes, using Christian ones. Here is where the shock sets in for anyone involved in the finance sector today. The biblical principles Mills draws on are these four: know what you are investing in, don’t reap what you didn’t sow, risk being lavish for good purposes, and don’t insure yourself too heavily as if you can control things like God.

But are these principles pipe-dreams in today’s financial world? How can an individual investor in a fund really know what is happening with their money? Isn’t speculating all about reaping what you didn’t sow? Is risk-taking really Christian? And isn’t insurance ‘good stewardship’?

Instead of nuggets, this chapter gave me gallstones. How is a humble arts graduate supposed to disentangle himself from the web of financial ethics in a world as complicated as ours? I’ll have to read some books that can’t be finished during a Melbourne-Sydney flight to find out.

But most importantly, my heart was warmed when I realised I had one more question: why did the authors ask what Jesus would do? It seems they were acknowledging the profoundly important and deep-rooted Christian background to our culture, and our need to keep testing ourselves against the wisdom of the Servant King.