His name was Ahmed, and he was on his way home to Pemba, the Tanzanian island north of Zanzibar. His mother, he said, was a doctor and his father worked for the Ministry of Education. He had just finished Form 5 at a Muslim school in Morogoro, and was going home for the summer before his last year. Then he would go to university, where he had great academic ambitions. He wanted three degrees: biology, physics and chemistry. Ahmed wanted badly to exceed the achievements of his parents.

"But first," he said, "I want to work as a 'guidi.' Do you know guidi?" he asked.

"You mean to take tourists to the East Coast?"

He looked disappointed. "No, guidi means ... in Swahili ..." He struggled for the words. "You don't know guidi in English?" he asked.

"I don't think so," I said.

"You know ... how do you say? ..." He went into a lengthy explanation, half in English, half in Swahili, about what I understood to be the person who goes into a house first, in secret, to throw bombs. I told him I understood, but wasn't sure what the word was in English. "Where do you want to do this?" I asked.

"In Palestine," he said.

"You want to throw bombs at Israelis?"

"No." He seemed reluctant, and went into another long explanation. First, he said, he wanted to study to get his three degrees and then go to one of the Hamas schools to learn how to construct bombs. He explained this with no trace of bitterness, but rather with the innocence of a boy describing his dream to be a fireman.

"I want to be the one who makes the bombs," he said.

I wasn't sure what to say, and a silence ensued, which I finally broke. "That must be a hard job."

The point was not lost. "Many people of Zanzibar," he said, "they want to go to England or Denmark to get a good life."

"But not you?"

"Not me. I want a tough life."

"How come?"

"Because," he looked out across the water, "I have never faced it."

"Yeah," I said, "me neither."

The waves crashed beneath us, exploding out into the surf. The sun grew red as it sank toward the horizon and tourists from the balcony of a nearby hotel grew louder and more obnoxious.

As we sat in silence watching the water and the dhows, I wondered what it was, exactly, that made him so sure he wanted to go a place he'd never been and make bombs for throwing at people he'd never met.

The more I thought about the question, the more it puzzled me. Ahmed was confident and polite, a boy to have over for dinner. He didn't look like a bomber, a terrorist. He certainly didn't want to kill me, but just to chat in the lonely interval while he waited to go home. Yet his belief in the politics of violence, rooted in a faith in the Koran, seemed unshakable.

Waves crashed under us in the growing pause. Questions rolled through my mind and since neither of us seemed to feel threatened by the other, I decided to ask one.

"So," I said casually, "how do you know the Koran is the truth?"

"Because," he said, "I read it and I know it is the truth."

"But how do you know?"

"If you read it, you can see: There is the truth."

"What about the Bible?"

"The Bible is also truth, but the Koran is more truth," he said.

"What do you mean?"

"Ah," he waved a hand dismissively toward the water, "because, you see, everyone has their different Bible. Everywhere you go, it is all different. But the Koran, it is all the same, each and every one." He held out two fists triumphantly. "The Koran is much stronger."

I appealed to his scientific side. "You know how in chemistry, when you have an experiment, you can't know something until you have the proof. What is the proof that the Koran is the truth?"

"Ah haa," he said, finally seeing what I meant. He told a parable about a light bulb and a dark room -- something about not knowing you are in darkness until you see light. It was a sort of paradox designed to make the head spin in revelation.

When my head did not spin, Ahmed looked perplexed and a little frustrated. "You will never see until you read the Koran yourself," he said.

"That's possible," I admitted, and in silence, we watched the sun sink below the sea.

"OK," he announced in a mixture of proclamation and plea, "I want to go now." I told him I had to leave, too. We both rose, turned our backs to the sea and walked partway down the road together.

At a crossroad, we exchanged invitations to each other's homes, as Tanzanians always do, and said a cordial goodbye. I went one way down the road and Ahmed the other. After walking a little, I turned around to look, just as he did the same, and our eyes met briefly before we both turned back and continued on our way.