About a third of the world's people have no toilet. This is both unsanitary and inconvenient. In villages, it's often customary for the women to rise at 5 a.m. and pay a visit to the field, and the men to make their pilgrimage an hour later. In cities, there are open cesspits, fetid back alleys and plastic-bag "flying toilets."
Nowadays, it's increasingly familiar to see people composing text messages while engaging in such demeaning public activities. As we learned this week, 4.3 billion people have access to a toilet, and 4.6 billion people personally own a cellphone. This means there are 300 million people in the world, equivalent to the population of the United States, who have a cellphone in their pocket but no access to a toilet.
To many of us, this sounds absurd: A toilet is a basic necessity, whereas a mobile electronic device still seems like a frill or a minor luxury. People with family incomes below $2 a day shouldn't be buying $20 devices, should they?
That was certainly how it was taken when most people read those figures from World Water Day, which marks a worthy campaign to get proper sanitation to more people in poor countries.
But let's not discount cellphones for the very poor, or question their priorities. Why would someone want to have a cellphone before a toilet? I have met a good many people, on four continents, who have a stick of beeping silicon in their pocket but no slab of wet porcelain in their house, and while none are happy with the lack of sanitation, none would consider their phone to be anything less than vital.
There are a number of reasons why a cellphone is as important as a toilet, if not more so, for those at the bottom of the barrel:
Toilets are about sitting still, phones are about movement. A toilet in your house will prevent disease and bring dignity and value to life. But life for the very poor is about constant change and risk. Poor people have to move house much more frequently than those with higher incomes; they have cash-flow problems and need to seize on ever-changing minuscule income opportunities.
They tend to make their livings from multiple sources - as economist Deepa Narayan has found, poor villagers manage by building "joint portfolios" of farming, small businesses and casual labour in the city, to hedge their risk across several platforms. As the four economists who wrote the recent study Portfolios of the Poor noted, the world's poorest people endure the "triple whammy" of "low incomes; irregularity and unpredictability; and a lack of tools."
Most of the world's poor now live in motion, with part of the family in the village and part on the margins of a city. There are more than 200 million Chinese families divided between village and city; they rely on instant mobile communications to avoid catastrophe and to find opportunities to escape their plight.
Poverty, in short, is vulnerable to sudden change. A phone at least provides a few more potential lifelines.
Phones can mean debt, but toilets can mean eviction. As anyone who's received a cellphone for Christmas knows, it's a gift that requires constant payments. In poor countries, cellphone use costs upward of $2 a month - so they can contribute to dangerous levels of indebtedness.
But they can also be ways out of debt. In Africa, small-hold farmers frequently use cellphone crop-information services such as Ghana's Esoko to locate buyers, get the best prices and find out what to plant based on futures markets - a useful service for a Western farmer but a lifesaver for a poor sub-Saharan one.
On the other hand, when an aid agency hooks up a toilet to your shack, there's the risk that your property value will be raised above the poor-family level: great if you own, but potentially tragic if you rent.
A phone won't stop your children from getting dysentery, but a toilet won't overthrow your dictatorship. Yes, the people of Eastern Europe managed to overthrow their autocrats in 1989 without cellphones. But they used very similar networks built on well-established connections. Among the new classes of the Middle East, the cellphone has become vital for communicating new opportunities - not just in income, but in politics.
Increasingly, it's the tool people are using for dramatic reform. It doesn't have the comforts of a toilet, but it can help you flush away that stinking mess.