EIGHT

      I moved silently through the dark trees. Rachel sounded like a blind bear blundering along behind me. On a Manhattan street she probably maneuvered like a pro halfback, but the woods were alien to her. I slowed until she caught up, then told her to hold on to the back of my belt. She did.

      When we were fifty yards away from the house, I said, “Do you believe me about Fielding now?”

      “I believe you worked with him,” Rachel said. “I’m not sure he was murdered. I don’t think you are either.”

      I stepped over a fallen log, then helped her over. “I know he was murdered. Only two people at Project Trinity opposed what was being done there. Fielding was one, and now he’s dead. I’m the other.”

      “Are you going to tell me about Trinity now?”

      “If you’re willing to listen. I think you understand now that it could be dangerous for you.”

      She sucked in her breath as briers raked her arm. “Go on.”

      “When you came to my house today, I was making a videotape to give to my lawyer. He was to open it if something happened to me. I never finished it. And the truth is, I’m worried about seeing tomorrow morning alive.”

      Rachel stopped in the overgrown track. “Why don’t you just call the police? Lu Li clearly shares your suspicions, and I think there’s enough circumstantial evidence to—”

      “City police can’t investigate the NSA. And that’s who oversees Trinity.”

      “Call the FBI then.”

      “That’s like calling the FBI to investigate the CIA. There’s so much ill will between those agencies that it would take weeks to get anything done. If you really want to help, become my videotape. Listen to what I have to tell you, then go home and keep it to yourself.”

      “And if something happens to you?”

      “Call CNN and The New York Times and tell them everything you know. The sooner you tell it, the safer you’ll be.”

      “Why don’t you do that? Tonight?”

      “Because I can’t be sure I’m right. Because the president could be trying to reach me as we speak. And because, as juvenile as it may sound, this is a national security matter.”

      Holding Lu Li’s whimpering bichon in my left arm, I put my gun in my pocket and pulled Rachel forward. Forty yards on, I saw a deeper darkness ahead. The trees gave way like thinning ranks of soldiers, and then a man-made wall stopped me in my tracks. When my eyes adjusted, I saw the door I had known was there. I opened it with my free hand and led Rachel through. We emerged into a moonlit bowl, lined with cut stone.

      “My God,” she said.

      The amphitheater looked as though it had magically been transported to the Carolina woods from Greece. To our right was the elevated stage, to our left a stone stairway leading up through the seats to the top row. Not far above that lay Country Club Road. The view down from the road was almost completely blocked by pines and hardwoods, but I could see the broken beams of headlights passing high above us.

      I took Rachel’s hand, stepped onto the stone floor, and led her to the edge of the stage. There I tied Maya’s leash around a low light stanchion. While the dog sniffed an invisible scent trail, I set the tape recorder on the edge of the stage and depressed RECORD. “This is David Tennant, M.D.,” I said. “I’m speaking to Dr. Rachel Weiss of the Duke University Medical School.”

      Playback gave me a staticky facsimile of my words. I looked at my watch. “We need to do this in less than ten minutes.”

      Rachel shrugged, her eyes full of curiosity.

      “For the past two years, I’ve been working on a special project for the National Security Agency. It’s known as Project Trinity, and it’s based in a building in the Research Triangle Park, ten miles from here. Trinity is a massive government-funded effort to build a supercomputer capable of artificial intelligence. A computer that can think.”

      She looked unimpressed. “Don’t we already have computers that can do that?”

      This common misconception surprised me now, but when I went to work at Trinity, I hadn’t known much better myself. For fifty years, science fiction writers and filmmakers had been creating portrayals of “giant electronic brains” taking over the world. HAL, the speaking computer of 2001: A Space Odyssey, had entered pop consciousness in 1968 and remained firmly embedded there ever since. In the subsequent thirty-five years, we had witnessed such a revolution in digital computing that the average person believed that a “computer that can think” was just around the corner, if not already within our capabilities. But the reality was far different. I had no time to go into the complexities of neural networks or strong AI; Rachel needed a simple primer and the facts about Trinity.

      “Have you heard of a man named Alan Turing?” I asked. “He’s one of the men who broke the Germans’ Enigma code during World War Two.”

      “Turing?” Rachel looked preoccupied. “I think I’ve heard of something called the Turing Test.”

      “That’s the classic test of artificial intelligence. Turing said machine intelligence would be achieved when a human being could sit on one side of a wall and type questions into a keyboard, then read the answers coming onto his screen from the other side and be certain that those answers were being typed by another human being. Turing predicted that would happen by the end of the twentieth century, but no computer has ever come close to passing that test. Using conventional technology, it’s still probably fifty years off.”

      “Didn’t that IBM computer finally beat Garry Kasparov at chess? I know I read that somewhere.”

      “Deep Blue?” I laughed, the sound strangely brittle in the amphitheater. “Yes. But it won by using what computer scientists call brute force. Its memory contains every known chess game ever played, and it processes millions of probabilities every time it makes a move. It plays very good chess, but it doesn’t understand what it’s doing. As a human being, Garry Kasparov never has to consider the billions of possibilities—many of them ridiculously simple—that the computer does. Kasparov’s acquired knowledge allows him to make intuitive leaps, and to learn permanently every time he does. He plays by instinct. And no one really understands what that means.”

      Rachel sat on the edge of the stage. “So, what are you telling me?”

      “That computers don’t think like human beings. In fact, they don’t think at all. They simply carry out instructions. All