It did here, too. Kennedy half-dollars weren't just coins in this alternate. They were amulets. Only rich men had them, and mostly wore them on chains around their necks. The coins were credited with everything from magically stopping bullets-more irony, when you thought about it-to curing smallpox.

Smallpox… Liz rubbed at her left arm. In the home timeline, the disease was extinct. But she'd had to get vaccinated before she came to this alternate. People here vaccinated, too-they remembered that much. Not everybody got vaccinated, though, and the disease still broke out every now and then. The pocked faces of survivors were… appalling.

And people from the home timeline did a brisk business selling perfect copies of Kennedy halves. Yes, it was taking advantage of superstition. But the superstition would have been there whether they took advantage of it or not. In other alternates, Crosstime Traffic sold religious relics of several different kinds. What was the difference, really? Liz had trouble seeing any.

For that matter, what was the difference between superstition and religion generally? Lots of people had spilled lots of ink and killed lots of trees and pushed around lots of electrons trying to define the answer. So far, most of what they said boiled down to What I believe is religion, and what those foolish people over there believe is superstition.

There was no evidence that knocking on wood made the world less likely to go wrong. There was no evidence that praying in a church or synagogue or mosque made the world less likely to go wrong, either. That didn't stop people from doing both kinds of things. When it first became plain that science explained how things happened-not necessarily why, but how-better than religion did, lots of “experts,” from Karl Marx on down, predicted that religion would wither up and die.