By Fergal Keane
BBC News, Kibera, Nairobi
More than half of Kibera's residents are unemployed
No phrase so commonly used about Africa can conceal quite so much.
I am talking about those two very familiar words "tribal violence".
They conjure up memories of the Congo and Biafra in the 1960s, Uganda and Burundi in the decade after that, all the way to the miseries of Central Africa in the 1990s.
Sadly the Western mind has been conditioned to accept a simplistic notion of what "tribal violence"' really means: people driven to kill each other by irrational atavistic hatreds.
Now the expression is being used again to describe the crisis here in Kenya.
Those who have nothing are looting those who have a little bit more
I wouldn't for a second try to deny that what happened in all the places described above involved some degree of ethnic motivation.
After witnessing at first hand the hatred of Hutu militiamen for Tutsi civilians in Rwanda I understand only too well how real or imagined ethnic difference can be whipped up by unscrupulous leaders.
Having spent the past few days in the vast Kibera slum in Nairobi I have naturally been giving this issue some thought.
I have met numerous Kikuyus who say they have been driven out by Luo tribespeople.
And I have also met Luos who speak of being disenfranchised by the Kikuyu.
At dinner the other night with old Kenyan friends one - who happens to be Luo - described going to an election night party with a tribally mixed group of friends.
This population has seen successive governments rob billions from the public purse in well-documented scandal
By the end the Luo and Kikuyus were arguing furiously. My friend felt a tribal rupture she had never experienced before in Kenya.
But the tribal issues are only the symptom. Go into the muddy, filthy lanes of Kibera and you find something approaching root causes.
I have spent the past few weeks warning people not to make facile comparisons with Rwanda, where up to a million people died in 100 days.
That was a state-planned and executed genocide. What is happening in Kenya is nothing like that either in scale or intent.
But one thing did strike me as scarily familiar. This is a conflict in which the poor are set at one another's throats.
Sanitation and electricity
In Kibera it is a matter of degrees. Those who have nothing are looting those who have a little bit more.
More than 50% of the people who live in this slum are unemployed. It has a child mortality rate that is between five to seven times the national average.
There are tens of thousands of Aids orphans. And there is no proper water or sanitation or electricity.
All this in a place with nearly a million people. As Walter Kibet, clinical officer with the charity Afrem put it to me: "You see the children getting sick and it affects every aspect of their development."
This population has seen successive governments rob billions from the public purse in well-documented scandal.
Add all this together and you get a sense of what might be driving the rage. It certainly isn't a simple issue of tribalism.
In the middle of all this are families like that of Ruth Awuma. She is married with six children and a husband who cannot work due to dreadful burn injuries. A lit candle fell on his bed while he slept.
Ruth rises every day at dawn and travels to work as a maid in Nairobi, returning home every evening just in time to put her younger children to bed.
I asked what her dream was. She didn't talk about a new president or democracy. Such things seemed abstract in her dark and claustrophobic home.
"I would love a water supply in my house," she said.
But you must know that is unlikely, I said.
Ruth laughed. "But I can pray," she replied.
It was about as eloquent a statement of hope as you could hear in Kenya these days.