One of the best examples of this, and one I’ve returned to frequently, is the case of ancient astronaut theorist David Childress and his alleged quotation from the Mahabharata on supposed nuclear fallout in prehistoric India. Childress “quoted” the Mahabharata as saying that ancient Indians experienced radiation poisoning and “their hair and nails fell out” as a result. But Childress wasn’t quoting the ancient Indian text (which would have been a primary source). Instead, he was reworking a “quotation” he found in a book by Charles Berlitz (a secondary source), which was not directly quoting the Mahabharata either. Berlitz was presenting a quotation from the English edition of Jacques Bergier and Louis Pauwels’s Morning of the Magicians, which gave an English translation of an erroneous French translation of a Sanskrit original. The primary source—the Mahabharata itself—actually says that “rats and mice ate away the hair and nails” of sleeping men.
But it isn’t just alternative authors who fall prey to secondary source problems. I also recently posted on the 300 year odyssey of a typographic error that continues to be given as a scholarly fact, namely that the Greek mythic hero Jason was first named Diomedes. This mistake, as I explained, derives from a typo in a late printing of a Renaissance guide to mythology, which itself contained a reading error on the part of the author. From the 1700s to today, almost no one has bothered to check the primary sources (actual ancient texts) to see that there is no evidence outside the typo for this alleged “fact.”
Similarly, in 1990 Martin Kottmeyer offered a hazy memory at 25 years’ remove of an episode of The Outer Limits that he thought first introduced the “wraparound” eyes of the aliens that abducted Betty and Barney Hill and was therefore responsible for parts of their abduction scenario. For the next two decades skeptics (including me, in my Cult of Alien Gods, since I had no access to the original episodes when I wrote the book) cited his claim without screening the original series, which in turn allowed UFO experts, who also did not watch the show, room to attack the claim since the episode in question, “The Bellero Shield,” does not actually feature wraparound eyes but rather slanted eyelids, and no abduction. (The “wraparound” eyes were actually in “The Children of Spider County,” airing five days before Hill’s hypnosis.) As far as I can tell, no one who either repeated or attacked the claim that the Outer Limits influenced the Hill abduction actually screened the series’ episodes for evidence until I did this summer, thanks to Hulu putting them all up complete and uncut online. The primary sources make plain that key parts of the Hill abduction uncannily parallel not one but three episodes all airing consecutively in the three weeks immediately prior to Barney Hill’s first hypnosis session in which identical motifs appear.
It isn’t always possible or practical to use primary sources for everything, of course. When looking up the date of the Battle of Hastings, we don’t go to visit the Bayeux tapestry or pull out Norman archives. We can be reasonably certain than an encyclopedia or history book can give us that information. This is because certain facts have been examined by a wide range of experts over centuries and can be traced, transparently, to primary sources. But the more that a claim departs from conventional ideas, the more important it is to be able to document it at its source. One reason the claim about Jason as Diomedes lasted so long is because it is, ultimately, so trivial. Why would anyone bother to make up something that affected precisely nothing and did not challenge convention in any substantive way?
By contrast, the ancient nuclear bomb claim has not achieved widespread acceptance because it is so transparently at odds with convention; however, even skeptics have simply accepted Childress’s “quotation” at face value, assuming that he was capable of correctly quoting from an ancient text that anyone could look up. This is a fatal assumption, and one that I fell victim to during the fourth season of Ancient Aliens, when I erroneously assumed that the program could correctly quote the Bible, when in fact it had confused the Bible with non-canonical texts. By trusting in accurate citation, I almost missed a major error.
It's an important lesson, and one that nearly every writer repeatedly relearns: no matter how easy it is to merely repeat from earlier writers, one must always, always check sources.