"We come," said the instructor, "at last to epistemology. The study of knowledge itself. What is knowledge? How do we measure it? What are the sources of knowledge and how do we know -- that we know?"

"Sounds like angels dancing with a pinhead," Gail muttered sotto voce.

The girl across the aisle giggled.

Encouraged, Gail continued in the same low voice. "Who knows what epistemology lurks?"

Another giggle.

"Miss Davis," the instructor said, calling on the unfortunate giggler.

"Yes, sir?" she said, first glancing sideways.

"Uh oh," thought Gail.

"Miss Davis -- it is Miss Davis, isn't it?" the instructor asked.

"Uh, yes, sir?"

"How do you know you are Miss Davis?" He glanced at a sheet of paper on his podium. "Miss Sidney Davis. How do you know that you're you and not someone else?"

"Are you seriously asking me that?" Her voice squeaked a little.

"Yes," he said. "Seriously." A titter ran around the room.

"Well, because ... I am, who I am because I remember being me." Miss Davis gave it the old college try.

"But is that knowledge, or just belief? Do you know that you are Miss Sidney Davis because you are, or do you simply believe you are Miss Davis because you remember your name?"

She frowned. "I know I'm me!"

The instructor smiled. The titter ran through the room again. It wasn't what the instructor said that made him funny, it was how he said it (he had a faint British accent) and the way his eyebrows seemed to do calisthenics when he had someone on the hook. "Do you now? But you can't tell me how you know?"

Sidney sighed. "I'm me, because I'm here and Sidney Davis takes this Philosophy class every Tuesday and Thursday, from 1:30 to 3:00 p.m." She tried to look triumphant but managed only a slightly fatuous smugness.

"I see," said the instructor. "But other students take this class. Perhaps you are one of them? Perhaps you are actually Gail Miller, instead of Sidney Davis."

She glanced across the aisle and giggled again. "I don't think so."

Gail's eyes rolled toward the ceiling.

"You believe yourself to be Sidney Davis. Is that all that is necessary for knowledge? Just belief in something?"

"Uh," the girl tried to look thoughtful but could not acccurately have been said to be thinking anything at all unless it was, "I must not say, 'oh, shit' out loud!"

"If I believe that you are actually Gail Miller, then are you still Sidney Davis?"

"Well, yes!"

"Are you certain?"

"I ought to know who I am!"

"Yes," the instructor agreed. "You ought. But other than a memory, and a class schedule, what reason do you have for believing yourself to be this Sidney Miller person instead of Gail Davis."

Sidney held up her hands and moved her forefingers past each other. "Other way around," she said.

"Oh, so now you believe yourself to be Gail Miller?"

The titter had grown and raced around the room again.

"No!"

"Why not?"

"Because I'm a girl and Gail is a guy?"

"How do you know that?"

The titter graduated to a laugh. The instructor held up his hand for silence, smiling but firm.

"Well, I mean, I ...." Sidney trailed off, looking across the aisle at Gail.

"Don't look at me!" thought Gail, wanting to dive for cover under a desk.

"I mean," asked the instructor, "Have you checked? Lately?"

Another laugh joined the class.

Sidney shook her head.

"After all, Sidney and Gail are unisex names, either of you could be the other from that evidence." Something between a snort and a chuckle tried to escape from the back corner of the room. A snuckle?

"Can't you just look at us and see?" complained Sidney.

"Well, if seeing is believing, is believing knowing? That is the question, isn't it?"

The bell rang, almost drowned out by a sudden guffaw of relief that swept the whole class to their feet.

"Dismissed," called the instructor to the fleeing students. "Read chapter eight over the weekend and be prepared to discuss how we know that we know what we know on Tuesday."

Sidney and Gail gathered their books and headed toward the door, too. "That Mr. Martin sure thinks he's smart," complained Sidney.

"No," said Gail, giggling suddenly. "He knows he's smart."

"Ho, ho. Want me to carry your books?" he offered.

"Sure," she gladly gave them up, stacking them in his arms. They headed on out, she snuggling softly against his taller strength. "I think you're awful cute when you're flustered," she said.

"Ho, ho. Next time, you can be his frog and get dissected, no thanks." He bundled all of their books under one arm so he could hug her against him, pleased that she thought he was cute, whatever the circumstance.

"Have a good weekend, kids," Mr. Martin called from the front of the class.

"We will," they called back and got the heck out of there.

"Don't be anyone I wouldn't be," added the instructor, smiling as the door closed behind them.