Years ago I heard a lecture by a scholar about the ancient Athenian calendar, which was a lunar calendar. It was obvious from what he said that the man did not realize that the moon is sometimes visible in the daytime. The man was a tenured full professor at one of the top universities in the US, in his 50s, a Rhodes Scholar with a Ph.D. from Harvard.
Oy veh! Are you sure that you did not misunderstand him?