[henkster]

“People thought the world was flat.” He continued, “People thought blacks and whites shouldn't marry. People thought blacks shouldn't be equal.

I'm sure it never occurred to him that in 100 years, our descendants will add: "People thought man could change the climate."

[Texas Eagle]

“People thought blacks and whites shouldn't marry. People thought blacks shouldn't be equal.

Yeah. Those people were your 'RAT friends in the 1800s. Before then it was none of the government's businesses who was married to whom.

[JoeFromSidney]

“People thought the world was flat.”

This is nonsense. From the time of Eratosthenes(276 BC - 194 BC), every educated person knew that the Earth was round, and knew how big it was. See the book Inventing the Flat Earth for the origin of the myth that people once believed the Earth was flat. From the classical Greeks through the Middle Ages up to the present day, people knew the Earth was round, and by an ingenious observation, Eratosthenes succeeded in determining its circumference, to an accuracy that agrees well with modern measurements.