He paused. "Nivek."

"Is that your name?"

"No...well, sort of...", he trailed off.

The man looked annoyed for a moment as though he had been tricked into an answer he hadn't prepared. And then he was gone again.

I couldn't tell how long it had been going on. It didn't matter.

"Can we start again?" I said a bit louder than necessary. It came out with an edge to it that I hadn't wanted him to hear.

This time he smiled. He wasn't very old. Forty, maybe. Forty-five.

His eyes were bright and hazel; neither shallow nor deep.

"What do you want to know?" he asked.

"Start from the beginning."

"I began from the end."

"Well then start from where you think I'll understand."

He smiled again. "You can't understand from there. You have to be here first. I can't bring it to you."

I was confused again. He'd kept this up for days now.

"Just tell me," I said.

"Axiom 1: For every constant velocity there is a third point from which an acceleration can be measured."

"What?"

He took a piece of chalk out of a pocket that disappeared as quickly.

"Look. Draw a triangle. Let's call the top point A and the bottom two points B and C. Now assume the viewpoint of A and trace your finger between B and C. Did you see it?"

"What? My finger? Of Course I did."

"No. I mean did you see your finger get closer then get farther away from A - you?"

"Ya... so?"

"That's acceleration. You moved your finger at whatever speed and you observed it as an acceleration. It's the same if you assume the viewpoint of your finger and observe A."

"Oh, so you're talking about motion is relative."

"Yes... No, I'm talking about how motion is relative."

"What's the point," I thought.

"The point," he said, "is you can use it. It's a key. When things move with respect to one another an energy field is created between them. It's either getting bigger or getting smaller. It's either expanding or contracting."

"I don't see it," I said. "How do you know that?"

"How do you not know it?" he aked. "Take it on faith then"

"I can't."

"Then you'll have to go backwards to find out. Let me show you. When someone stands by a track they feel pulled towards the train as it passes them and then a bit in the direction of the train's travel."

"That's from a vacuum that the train makes, right?"

"No. The train accelerated towards you and pushed you back a bit and then as it passed you it stretched the field and you felt pulled towards it. It's the same thing when you stand on a bridge over a fast river you feel pulled down and in the direction of the flow. Or better still, You start to do something which causes an energy field between you and your environment. And pretty soon you get interrupted. People and things collapse into your field. When you talk with a friend and children are present, they collapse the field between you and whatshisname by getting inbetween."

"Social gravity," I joked.

"Yes! Well, almost. It's a matter of orders of magnitude."

"Wait," I cut him off. "So a cop with a radar gun isn't actually getting your speed, Is that right?"

"Right. Except when he's directly on your line of travel. The radar will measure your relative velocity to his position. The farther off the road he is, the slower the radar will clock you the closer you are to passing him."

"So if he's aiming across the road and you drive by, the gun will not show that you are speeding."

"Right."

"So let me see if I've got this," I said. "For anything moving along a path then its motion is perceived differently from every other point."

"Pretty much."

"Then that's why an accident with fifteen witnesses will give you fifteen different accounts of what happened."

"Yes," he said "this society works on the average viewpoint. Sort of an average truth. Not really truth at all."

It was more than I wanted to know.