"I don't know if anyone told you," he started, still half-singing and cheerful, "but I have a brain tumor that affects my memory."

I nodded.

"Please forgive me for asking this, but I do this with everybody. Could you tell me your name again and how it is that I know you?"

"Um...my name is Dan. Dan Levitin."

There was neither recognition nor unrecognition. Just a calm, interested face staring back at me.

"We were students together at Stanford," I continued. "We took a couple of psychology classes together."

"Oh, yes, I have a degree in psychology."

"We were in Professor Pribram's class, and we worked in a lab together, Roger Shepard's lab."

"Who?"

"Roger Shepard. He had a music and perception lab."

"Wow. That sounds like it must have been interesting. What did I work on there?"

"I don't know. I guess ... I guess I was absorbed in my own work. I'm really sorry."

"That's okay. Did I like being in the lab?"

"Yes, I think you did. I mean, you never complained. You always seemed pretty focused."

"That's good. I'd hate to think that I was doing something I didn't enjoy." He was sitting on the edge of the old sofa and I could see that the pillows were caved in under him. "So we were students together. I guess that was many years ago. Did we stay in touch after that?"

"Well, we ended up working, a few years later, for the same company. A research corporation in Palo Alto."

"Did we work together?"

"No, we were in different divisions. You worked with Joy, and I worked with Bob. But we saw each other from time to time, and I was interested in what your group was doing. Your team gave a really good presentation during the annual roundup. I remember you had worked on a very clever new musical instrument called the 'bead box.' People could move different beads around on spindles, and the beads would play different musical licks. It was a way for non-musicians to have fun with music, without having to devote themselves to years of practice."

"Huh?" he said, looking at the ceiling, "the 'bead box.' Doesn't ring a bell. But I don't get many bells ringing these days!"

"Well it was very cool."

He looked over at me. "So, were we friends?"

I just stared. Would it be rude if I told him that I never really thought of him as a friend? I mean, if one person thought of another as a friend, and the other person denied it, that would be hurtful. But Tom had no memory of me one way or the other. As I was thinking this, he spoke.

"It's okay. There's often this . . . gray area, I guess you'd call it, in human relationships, isn't there? We meet people, we see them every day, we say hello, but we don't really know them. We say they're our friends, but really, you can't be friends with the hundreds of people you meet, can you? It's enough that we had a shared history together. We were in the same places for a time. We were part of each other's fabric." He made a rubbing gesture with his fingers and thumb.