The neighborhood of Ravenna extends for ten tree-lined blocks from the northern border of the University of Washington to the throat of a gorge of trees and meandering streams known as Ravenna Park. Ravenna's proximity to the university makes it a housing favorite for students and faculty, though the two groups don't peacefully coexist. Rather, there seems to be a line of demarcation between the campus and the park, signaling the end of one group and the beginning of the next. You'd expect that houses closer to the U would be more in demand and thus less affordable, but the reverse was the case. It was the students who lived here, pushing the educators farther out for a longer walk to work.

Since my work deals with logic, I'm always on the alert for its absence. I mentally filed the observation for later consideration.

Zelda parked on a narrow street that bordered Ravenna Park. I was familiar with the area. The street sported the moniker Candy Cane Lane, due to the incredible coruscation of lights that ornamented the homes during the Christmas season. Sounds of laughter and music emanated from a gabled brown house. I followed Zelda up the stairs and inside.

The interior of Doctor Julius Dexter's home was high-ceilinged, multi-windowed, and off-white, a fitting defense against the dark wet winters of the Pacific Northwest. About two dozen people were milling around a large living room. A few more stood about in an adjoining room with well-stuffed bookshelves. This looked to me like Doctor Dexter's office.

"You mingle," said Zelda. "I'll get us some wine and try to spot our host."

She launched into the current of party traffic, navigating past several islands of intellectual repartee toward the kitchen. She was stopped here and there by men, many of them bearded, who waved their wineglasses to emphasize their wisdom. As she chatted and gestured, I noticed the rhythmic swaying of her shoulders and neck as she talked. There was something quite enticing about this woman. Apparently the academic crowd agreed.

Instead of mingling as instructed, I walked into Dexter's office and studied the bookshelves, hoping to learn more about our host. The books, mainly a combination of legitimate and pseudo psychology, history, and anthropology texts, were methodically arranged by subject and author.

The lower shelves held mostly paperbacks. I recognized this as a collection of mystery novels: two solid rows of everything from Holmes to Hammett.

I was leafing through Conan Doyle's The Adventures of Sherlock Holmes when a voice behind me said, "It's a nice collection, isn't it? Are you fond of mysteries?"

The voice came from a tall, wide-shouldered man who appeared to be in his mid-thirties. He rocked on the balls of his feet as if trying to increase his stature.

"You could say that," I told him. "I dabble in collecting mysteries from local authors."

He smiled. "In that case, allow me to introduce myself. My name is William Wordsmith."

"Ray Gabriel," I said, shaking his hand. His dark gray eyes were framed by brows that now lifted expectantly. He seemed to be waiting for me to say something else. I decided to wait him out.

"The mystery author," he prompted.

"I'm sorry," I said. "I'm not familiar with your work."

"Not familiar with my work?" I felt awkward until he added, "Well then, you are indeed just a dabbler."

I have this problem with suffering fools gladly. In my book the biggest fool is the presumptuous one. Wordsmith - the obvious pseudonym suggested arrogance - was still rocking on his feet in front of me, awaiting my response. "So, please enlighten me," I asked. "What have you written?"

He started to answer, but was interrupted by Zelda. She approached on the arm of a young, handsome man. His olive face with its finely sculpted nose was familiar, but I couldn't quite place him. Though several inches over six feet tall, his body was slightly bowed, as though frozen in supplication. Before they reached us, the man stopped to talk to a young woman, and Zelda continue toward us.

"I see you two have met," she said, gesturing to Wordsmith.

"Yes," I said. "Mister Wordsmith was just telling me about his novels."

Zelda smirked and said, "Oh, he was, was he?" The tall man came up beside her and nodded toward Wordsmith. Zelda grabbed his arm and entwined it around hers. "Ray, I want you to meet Father Vincent Aquilino, a new priest at University Cathedral."

"We've already met," he said, "in a manner of speaking."

Of course. Aquilino was the priest I had seen in the cathedral the morning of Father Peter's fall.

"Ray, forgive me," he continued. "Between the police and the parishioners I didn't get a chance to talk to you the other day. It must have been quite a terrifying experience."

I nodded. "How is Father Peter doing?"

"Still in a coma. They don't expect him to come out of it. To tell you the truth, the life support equipment is the only thing keeping him going. It's just a matter of days, the doctors tell us."

"I'm sorry." I didn't know what else to say. I felt uncomfortable talking about this in a room full of strangers.

Zelda steered the conversation to less awkward ground. "Ray is here as my guest, Father. He's doing exciting work in the Computer Sciences Department, teaching computers to think logically."

"Please tell us more about your logic machine," said Wordsmith. "I thought computers were logical by definition. How is yours different?"

Wordsmith settled himself into a high-backed chair. Zelda and I shared a settee, and Father Aquilino sat on its arm.

"Though it's true that computer programs use logic," I said, "they're essentially brain dead. They don't think by themselves. Instead they rely on the human programmer. My thumbrule system, as I call it, takes the computer a step further. By mimicking the problem solving powers of a human expert, the system makes logical deductions. It reasons."

"How does it accomplish such a characteristically human task?" asked Wordsmith. He reached over to a chess set on the coffee table in front of him, picked up the white queen and studied it."

"By applying thumbrules, facts, and deductions."

"And what the hell's a thumbrule?" Wordsmith asked. His tone was irritated, or perhaps dismissive. In either case, it riled me. I watched him return the white queen to the board and noted that he placed it on a different square than he had picked it up from. Maybe he was in the middle of a game with Dexter. If he was that good a friend, maybe I should make an effort to be polite.

"A thumbrule is like a rule of thumb, but not quite," I said. "Like a maxim or an adage. You know - a general statement accepted as fact whether or not it's been proven."

"You mean like, 'All's fair in love and war,'" said Wordsmith, looking over at Zelda.

Returning his gaze she smiled and said, "Or 'All that glitters is not gold.'"

Wordsmith bowed slightly. Their eyes remained locked on each other. I knew there was more going on here than met the eye. Father Aquilino added, "Or 'God's in his heaven, all's right with the world.'"

"Those are all good examples," I said. "But let's take as our thumbrule 'All men are mortal.' To get a computer to think like a human, you start with 'All men are mortal' then add a specific fact, like 'Socrates is a man.'"

"So," said Zelda, "if you put the two together, you can deduce that Socrates is mortal."

"Right. The progress goes from thumbrule, to fact, to deduction. Humans use this kind of reasoning every day to make decisions. It's how I've gotten my computer to think."

"What about Christ?" asked Father Aquilino.

"Excuse me?" I said.

"Christ was both God and man." He said it gently, expectantly, as though prodding a smart student to think through a math problem.

"Well, Father," I said, "I'm afraid my system would deduce that Christ was mortal. He died, after all."

"But He rose again," said the priest. "According to the Christian faith, He is immortal. Wouldn't that cause you to rethink your thumbrule?"

I turned to see him better. His gentle smile was unreadable. "Father," I said, "no disrespect intended, but a man can't be both mortal and immortal at the same time. It simply defies logic. And my system can deal only with logic. At least that was my position until last week."

"And what happened between then and now?" asked Wordsmith.

"I had what you might call a revelation. Last Sunday morning, as a matter of fact, right before Father Peter's fall. I've taught my thumbrule system to think logically, but it occurred to me that humans don't think logically. Just look at religion. No offense intended, Father."

"None taken, Ray."

"Belief systems are the key," I said. "I need to incorporate not only thumbrules, but a worldview into the program. Something that will account for how different people come up with different conclusions from the same set of facts."

"But Ray, aren't you perhaps biting off a little more than you can chew?" Wordsmith asked. "Belief systems are murky things, a combination of art and science, which are difficult to wed together. Similar to writing a mystery. As a matter of fact, I think you'd find it impossible for a machine to unravel a mystery crafted by a true master of the art."

"A true master," I repeated. "You wouldn't be referring to yourself by any chance, would you?"

Zelda coughed in mid swallow. Waving away the sarcasm, Wordsmith said, "I've received some small praise for my work, you know. One reviewer compared my style to Agatha Christie. Said it matched her masterpiece Ten Little Indians for intricacy of plot."

"Christie's writing is crap," I said. "Those contrived ten-people-trapped-in-a-room situations. Her sleuths can't compare when it comes to the real genius of logic." I held up the Sherlock Holmes book that I still held in my hand.

As the intensity of our conversation had risen, several party-goers had wandered into the study and clustered nearby. Wordsmith said, "If Sherlock is such a master logician, he should be full of thumbrules. You've got the book in hand. Why don't you show us some of his brilliance?"

I opened the book and looked for a typical Sherlock Holmes maxim. "Here, in The Speckled Band. Sherlock uses a thumbrule to make one of his brilliant deductions." I read:

I was then much surprised and interested on glancing down to observe that, though the boots which she was wearing were not unlike each other, they were really odd ones, the one having a slightly decorated toe-cap, and the other a plain one. One was buttoned only in the two lower buttons out of five, and the other at the first, third and fifth.

"Those are the facts," I said. "Now Sherlock provides the thumbrule." I read:

Now when you see that a young lady, otherwise neatly dressed, has come away from home with odd boots, half-buttoned, it is obvious that she came away in a hurry.

"Once you identify the thumbrules, the trick of getting a computer to think like a human is easy. Thumbrules are key. 'I thumbrule, therefore I am.'"

Zelda laughed. "Listen to you, the Descartes of computer science."

Aquilino slapped his fist into his open palm. "What do you think, Ray, of using Sherlock Holmes' deductive process to expand your thumbrule system? You could feed mysteries into it - novels and short stories - and train your Sherlock Holmes in a box to solve them."

The concept seemed to be a hit with our growing audience. Murmurs of appreciation were punctuated by "great idea" and "cool concept."

"It might work," I said. And it might just make the perfect prototype. Now I'd really need the aid of Julius Dexter. Creating a belief system out of thumbrules would be the key in getting Sherlock-in-a-Box to think properly.

I needed the prototype to be both entertaining and instructive if I was going to get this thing to market. Yes, I had signed a non-compete clause with my former company, just as Zelda had said. But the contract stated that I couldn't use private funding for any competing product. Nothing had been said about public funding. The university's incubator program was the main reason that I had re-joined academia.

Wordsmith said, "But first you have to explain why you're putting Sherlock Holmes in a box instead of Agatha Christie. Everyone knows that Ten Little Indians is the classic mystery."

"Agatha Christie missed the point of a good mystery in Ten Little Indians," I explained. "Unlike Christie, Conan Doyle makes sure all the clues are there for the reader, thanks to Sherlock's keen powers of observation."

"Heightened by a dose of cocaine, as I recall," said Wordsmith. The audience, which had now grown to a dozen or so, cheered heartily. Wordsmith smirked and fingered a black bishop on the chess board. I glanced at Zelda for support. She nodded sharply at me in encouragement.

"The mystery reader as detective should be able to chain the thumbrules and facts together as well as the computer does. But he doesn't. And why?"

"He'd probably be disappointed if he did," said Father Aquilino. "Who wants to solve the mystery too easily?"

"Exactly," I continued. "It's a fine line. If the puzzle is too simple, the reader is unsatisfied. But if it's not simple, the reader waits for Sherlock to sift through the clues in creative, imaginative ways to find answers that fit."

"And that's what you would call chaining his thumbrules together?" Father Aquilino asked.

"Yes!" I said. "The thumbrules represent his sleuthing expertise. He looks at the clues, chains his thumbrules and facts together, and crafts a solution. The reader recognizes that the solution makes perfect sense. He taps his head and thinks, 'Of course!'"

"And kicks himself in the butt because he didn't guess it," Zelda added.

"So," Wordsmith intoned dryly, "that's the feeling Conan Doyle wanted to engender in his reader." He cast a sweeping glance at the audience. "The rewarding feeling of having his butt kicked!"

More murmurs of approval. I wondered how many among the audience were mystery writers. Did they really agree with him? And why didn't the academics in the group see he was using wisecracks in place of a real argument? As their chuckles subsided, someone started chanting, "Kick butt, kick butt." Some of the others chimed in. They were really enjoying themselves. What fun.

It was obvious to me that I could win this argument technically but might lose the battle. Fortunately, Father Aquilino chose that moment to comment, "And your argument, Ray, is that something like Ten Little Indians doesn't kick, er, doesn't give the reader that feeling of 'Of Course'?"

"Well, I must disagree," said Wordsmith. "The plot of Ten Little Indians is wonderful. It keeps the reader guessing the murderer's identity right to the end. As the characters get killed one by one, you have to shift your hypothesis until finally only two remain."

"And by the rules of the game," said Zelda, "one has to be the murderer."

"Perhaps you shouldn't say more, Zelda," said Wordsmith, "or you'll give away the mystery. And you think, Mister Gabriel, that your computer program could unravel Christie's plot?"

"No," I said, "Sherlock-in-a-Box would fail, because Christie's plot isn't logical. With only two people left alive, it turns out that the murderer was one of the other eight, who was supposed to have been dead."

Though Wordsmith recoiled as if he'd been slapped, I pressed on. "Why not give away the trick? No reader could possibly have figured it out."

"Because the author plays a trick on you," said Aquilino. "She goes outside the rules of the game."

"Right. So when the answer to the riddle is provided, there is no feeling of 'Of course!'"

"And there's no kick in the butt!" said the priest excitedly.

"Exactly!" I sat against the cushion with the heady feeling of triumph. Despite Wordsmith's glowering silence, the group applauded. Someone slapped me on the back, and Zelda playfully patted my knee. I seemed to have been pronounced the victor in the debate.

Wordsmith pondered a spot on the floor, his eyes moving rapidly as though in REM sleep. Then he focused his eyes on me. His voice was low and even, but penetrating.

"I've enjoyed our discussion, Mister Gabriel," he said, "but I must be getting back to my guests." He stood up. The folds in his face made his eyes look small and ferret-like. He caught Zelda's eye. "Care to join me?"

"In a minute. I want to talk to Ray."

He glared at Zelda, and hidden messages seem to pass between them again. I turned to Father Aquilino and whispered, "His guests?"

"Yes," he said, obviously embarrassed. "I'm afraid I didn't understand what was happening right away. You may have guessed that William Wordsmith is a pen name."

I gripped my forehead and groaned. "For Julius Dexter." It seemed I had lost the war after all.

Regaining his composure and his ferret's smile, Wordsmith/Dexter said, "I'm putting the final touches on a short story I've written. What do you say, Ray, to a friendly challenge? I'll pit my mystery story against your computer program, and may the best man win."

"Delightful!" said Father Aquilino. "Zelda and I can act as referees."

I wasn't so sure. "What would be the ground rules?" I asked.

"That's easy," he said. "We'll use your own principles for a successful mystery. I'll read my story up to the point where the referees have sufficient information to solve it. You can put the facts into your computer program. If Sherlock can solve it, you win. But if no one solves it, I win."

"As long as it also gives Vincent and I a kick in the butt," added Zelda.

"You're on, Dexter," I said.

"Such a duel of egos," chirped Zelda. "Hopefully this isn't a duel to the death. But there should be some stakes, shouldn't there?" She reached over, picked up her Chardonnay, and made a show of slowly crossing her legs. All eyes on her, she twirled the stem of the glass in her fingers. "I volunteer to reward the winner personally," she said.

Dexter studied Zelda's face. She returned an unblinking stare, her eyes cool and blue. I felt caught in the middle of some game these two were playing.

"Father," said Dexter, "let's invite Mr. Gabriel to our get-together this Tuesday. We can continue our discussion then."

With that, he walked away. Many in the room trailed after him, laughing and talking animatedly.

Zelda patted my hand and stood up. "See you soon," she said.

"I thought you wanted to talk to me about something."

"Let's save it for later," she said. She took Father Aquilino's arm, leading him from the room. "Father and I have some ground rules to work out." The priest glanced back in concern while Zelda laughed gaily.

Such a tease she was. Just as well she wasn't my type.