In the ‘Ptolemaic system’, the planets, the sun and the moon each occupied a separate rotating sphere around the Earth. In Europe and many parts of Asia, this was assumed correct for 1,400 years.

The old Ptolemaic system in which the planets orbit the Earth in cycles and epicyles was actually a valid approach. We say that the orbits are elliptical, but an ellipse is an epicycle; ...

In other words, while the Ptolemaic System was objectively incorrect, it was very much right for its time. All of this unexpectedly came to mind while discussing self-driving cars.