Should a traveller, returning from a far country, bring us an account of men, wholly different from any with whom we were ever acquainted; men, who were entirely divested of avarice, ambition, or revenge; who knew no pleasure but friendship, generosity, and public spirit; we should immediately, from these circumstances, detect the falsehood, and prove him a liar, with the same certainty as if he had stuffed his narration with stories of centaurs and dragons, miracles and prodigies.On reading this in An Enquiry Concerning Human Understanding, it occurred to me that Hume had of course never had a chance to read much of the writing concerning certain distant nations that one read in the US between about 1970, or to see its widespread reception as simple truth.
Widespread, but not at all universal. Herbert Simon wrote, in Models of My Life, of a trip to Sweden in 1969:
... But the meeting with Jan Myrdal, and his significant other, was fascinating. Myrdal had written an excellent book, A Chinese Village, about peasant life in the People's Republic of China--with a distinct Maoist slant but descriptively accurate. That is, it sounded just right for peasants. More recently, he had been in Albania. Without blinking, he told me, "Some of the peasants had poor land in the mountains, others much better land in the valleys. So they held a great meeting, and they all agreed voluntarily to make exchanges in their lands, so they all would be equal."
Now here I applied the Travel Theorem. I had never been to Albania, but I had encountered peasants, in the United States and Mexico, and even in Germany and France. And I had read accounts of many peasants in many lands at many points in history. The probability of Myrdal's statement was far too low to be rescued by a single eyewitness statement.