Globalisation has left some people facing dilemmas for which history is no guide. The BBC's Steve Bradshaw travels to the island of Lamu off Kenya to find out what the influx of Western wealth means to devout Muslims.
Abdulkarim says working for tourists could compromise his faith
Abdulkarim needs money to pay off his school fees. And on this wild ocean coast, the quick way to make cash is to work for Western tourists. The problem is, Abdulkarim doesn't want to work for the glamorous newcomers, convinced it would offend his Islamic convictions.
But if he doesn't, he could yet face a future hawking tomatoes, instead of fulfilling his dream of becoming a doctor.
It's a tough choice, especially for an 18-year-old who has just had the best exam results of the year.
Today Abdulkarim's playing football on Lamu's sand pitch with his old school friends Abubakar and Arafat. They're all devout Muslims. And they all face the same dilemma, they just can't agree how to resolve it.
Watching them on the football pitch, you would think that Abdulkarim and his friends share common values and aspirations - and not just to be an African David Beckham.
But, while sympathizing with Abdulkarim's tourist boycott, Abubakar has joined up rather more hesitantly. He just hopes he can still find a way of training to be a language teacher.
In the meantime, the laid-back Arafat reckons both his friends are in danger of closing down options too fast. He sympathizes, but doesn't think there is anything wrong with working for Westerners. Not only does he sail dhows for the tourists, Arafat jokes that he would like to have a European girlfriend, just like some of his friends have done.
Tourists are attracted by the Island's beauty and slow pace of life
At first glance, it appears untouched by the 21st century - the only vehicle is an ambulance, many women are veiled, donkeys and dhows compete for its transport franchise. But there's one trend Lamu isn't immune from - and it's called globalisation.
Lamu's a Marrakesh in the making - its languorous beauty has attracted models, Britart heroines, European princesses (along with African old-timers). Those white-walled houses the tourists are buying up probably cost more than a Moroccan riad.
They are the kind of folk celebrated by their needs. If you're looking for a way to pay your school fees, they might be just the sort of people you want around. You can show them round the island, concierge their homes, fix their drinks...
While there is no wild hedonism - at least in public - many of the stricter Muslims like Abdulkarim are convinced the incomers include some drug- taking, promiscuous types. And that's why he's been manning a tomato stall, his dream of becoming a doctor stalled, at least for a while.
Edge of Islam
But, all is not lost, if he can't be a medic, Abdulkarim wants to be an Imam. And even an outsider can see he is bright, sensitive and strong-willed enough to be a fine mentor.
We want from Westerners their knowledge, but not their culture
Mahmoud Ahmed Abdull Kadir, Imam
For our three students, finding the edge of Islam - where the borders are - remains a life-changing issue.
As we left the island, Abdulkarim was standing by his decision not to work with tourists, Abubakar was still just about taking his side, while Arafat was happy to carry on sailing dhows for the friendly, moneyed strangers - who are generally welcomed here.
Arafat could see his friends' point of view - but kindly wondered if Abdulkarim's rigour may not have more to do with character than religion.
And there is a wider dilemma, which could affect us all.
The three students' Imam puts it this way: "We want from Westerners their knowledge, but not their culture."
The school has certificates dating back 20 to 30 years
It's a friendly, low-key rebuke made while selling freshly baked loaves... but he does look hurt when he says Islam's currently on the losing side. It's a reminder that this debate reaches down the centuries, and far beyond the north-east Kenyan coast.
And so we leave our friends with choices still to make.
But, it's worth remembering that in the days before globalisation, many other students never had such an opportunity. In the headmaster's cupboard are certificates going back 20, even 30 years.
The students who earned them could never afford to claim them. We can only speculate what difference that made to their lives.Life on the Edge begins on BBC World News on Tuesday 5 August at 1930 GMT. The films were made for the BBC by TVE.
(Will comment on it later..in the mean time, what do you think about it?)