I tried to relax. "What do you want to talk about?" I said.

"The Century War," said the Time Traveler.

I blinked and tried to remember some history. "You mean the Hundred Year War? Fifteenth Century? Fourteenth? Sometime around there. Between . . . France and England? Henry V? Kenneth Branagh? Or was it . . ."

"I mean the Century War with Islam," interrupted the Time Traveler. "Your future. Everyone's." He was no longer smiling. Without asking, or offering to pour me any, he stood, refilled his Scotch glass, and sat again. He said, "It was important to me to come back to this time early on in the struggle. Even if only to remind myself of how unspeakably blind you all were."

"You mean the War on Terrorism," I said.

"I mean the Long War with Islam," he said. "The Century War. And it's not over yet where I come from. Not close to being over."

"You can't have a war with Islam," I said. "You can't go to war against a religion. Radical Islam, maybe. Jihadism. Some extremists. But not a . . . the . . . religion itself. The vast majority of Muslims in the world are peaceloving people who wish us no harm. I mean . . . I mean . . . the very word 'Islam' means 'Peace.'"

"So you kept telling yourselves," said the Time Traveler. His voice was very low but there was a strange and almost frightening edge to it. "But the 'peace' in 'Islam' means 'Submission.' You'll find that out soon enough"

Great, I was thinking. Of all the time travelers in all the gin joints in all the world, I get this racist, xenophobic, right-wing asshole.

"After Nine-eleven, we're fighting terrorism," I began, "not . . ."

He waved me into silence.

"You were a philosophy major or minor at that podunk little college you went to long ago," said the Time Traveler. "Do you remember what Category Error is?"

It rang a bell. But I was too irritated at hearing my alma mater being called a "podunk little college" to be able to concentrate fully.

"I'll tell you what it is," said the Time Traveler. "In philosophy and formal logic, and it has its equivalents in science and business management, Category Error is the term for having stated or defined a problem so poorly that it becomes impossible to solve that problem, through dialectic or any other means."

I waited. Finally I said firmly, "You can't go to war with a religion. Or, I mean . . . sure, you could . . . the Crusades and all that . . . but it would be wrong."

The Time Traveler sipped his Scotch and looked at me. He said, "Let me give you an analogy . . ."

God, I hated and distrusted analogies. I said nothing.

"Let's imagine," said the Time Traveler, "that on December eighth, Nineteen forty-one, President Franklin Delano Roosevelt spoke before a joint session of Congress and asked them to declare war on aviation."

"That's absurd," I said.