Think, for a moment, about the stories that your family likes to tell about itself. They are probably miniature versions of the American story, with progress as the central theme.

Maybe your great-grandparents arrived here as striving immigrants, and you now talk about how proud they would be. Maybe you’re the first college graduate or doctor in the family, and your parents brag about you. Maybe your grandparents couldn’t vote because of their skin color — and then had the thrill of voting for a president with the same skin color.

These stories aren’t about only your family. They are also stories of tribal pride — about Italians, Irish, African-Americans, Jews, Asians, Latinos and others — that make people feel part of something larger.

When progress is the norm, it feeds on itself. People can trust that their own sacrifices will usually pay off. They can endure hard times without becoming cynical and can be generous toward others.