Once, pretty much everywhere, beating your wife and children was regarded as a father's duty, homosexuality was a hanging offense, and waterboarding was approved -- in fact, invented -- by the Catholic Church. Through the middle of the 19th century, the United States and other nations in the Americas condoned plantation slavery. Many of our grandparents were born in states where women were forbidden to vote. And well into the 20th century, lynch mobs in this country stripped, tortured, hanged and burned human beings at picnics.

Looking back at such horrors, it is easy to ask: What were people thinking?