At lunch, three days later, while we were waiting for our order, he opened a small notebook. "Ever hear of feedback effects?"
"Not enough to have it clear."
"You know the snowball effect, though."
"Sure, start a snowball rolling downhill and it grows."
"Well, now—" He wrote a short line of symbols on a blank page and turned the notebook around for me to inspect it. "Here's the formula for the snowball process. It's the basic general growth formula—covers everything."
It was a row of little symbols arranged like an algebra equation. One was a concentric spiral going up, like a cross-section of a snowball rolling in snow. That was a growth sign.
I hadn't expected to understand the equation, but it was almost as clear as a sentence. I was impressed and slightly intimidated by it. He had already explained enough so that I knew that, if he was right, here was the growth of the Catholic Church and the Roman Empire, the conquests of Alexander and the spread of the smoking habit and the change and rigidity of the unwritten law of styles.
"Is it really as simple as that?" I asked.
"You notice," he said, "that when it becomes too heavy for the cohesion strength of snow, it breaks apart. Now in human terms—"
The chops and mashed potatoes and peas arrived.