I have this signature line that is appended to my posts on a writer's forum that I frequent, and it goes like this: "It ain't what you don't know that gets you into trouble. It's what you know for sure that just ain't so." That just about sums up my most important philosophy. Now, when you quote somebody it's just polite to give the author some credit. So here is the credit line that I use for that quote: "lots of people."
This afternoon a helpful member of that forum dropped me a line to point out that Mark Twain was the actual author of the aphorism I have been using in place of my own wit. But I'm not too sure my correspondent is correct.
My research has shown conclusively that Mark Twain said just about everything that has ever been said. He must have said so much that his acquaintances frequently had to ask him to "just shut up, Mark; just shut the f*** up!" I surmise that he was very boring at parties, always yammering on with some kind of folksy wisdom or other and never giving a fig for what anybody else had to say. (I am very sorry if you are a big Mark Twain fan or something, but the truth is the truth -- as Mark Twain said.)
You can be pretty sure that Samuel Clemens once said, "Pass the gravy." But that doesn't mean he was the original author of that phrase, either, under his own name or his assumed one. That's why I don't give him credit in my signature: that he deserves that credit is something (one of many things) I don't know for sure.
You will read that Twain said, "Everybody talks about the weather, but nobody does anything about it." But you won't find those words or any like them in anything he ever wrote. A friend of his, Charles Dudley Warner, an editorial writer for the Hartford, Connecticut Courant newspaper, wrote that "A well known American writer once said..." the remark. But he did not name the well-known writer so we have no idea who he was talking about and everybody just ASSUMED that Mark Twain MUST have been the guy because he was, well, a well-known author and he was known to be clever and it sure sounded like something that the guy who wrote about celebrated jumping frogs might say. And there's no proof either that Twain remarked that the coldest winter he ever spent was a summer day here in My City of San Francisco.
You will also find references to Twain writing that, "There are three kinds of lies: lies, damned lies, and statistics." He did write that, but he was quoting the British statesman Benjamin Disraeli and took no credit for the witticism (or is it "criticism?").
Now, most folks will swear that Mark Twain is indeed the author of the line about what you know that ain't so, but I suspect none of them have taken the words to heart in the very matter of who said the thing or who deserves the credit for the saying of it.
See, Mark Twain was a writer (and a very good and very prolific one). But if you have a look at all 20,400 citations that Google will dish up for you, not a single one of them tells you WHERE or WHEN Twain uttered, wrote, or thought up this little tidbit. And that's the sort of thing that makes me just a bit suspicious about his authorship. You'd think if Twain wrote it down -- or if somebody heard him say it and reported it somewhere -- somebody would have by now gone to the trouble to find out just when and where and by what motivation he made the remark.
I am the proud owner of an entire fleet of respected scholarly books of quotations, from which I borrow ideas often and without shame. I have looked through every one of those books and, not very much to my amazement, the "what you don't know" quote appears nowhere in any of them. I must assume that the reason the editors of these weighty tomes have ignored one of the best-known witticisms of America's most renowned humorists is that they're not too sure themselves that he actually said it. They are completely mum on the matter, not even printing the saying with the note: "apocryphal."
Perhaps Twain did say or write the words, or something like them. Closest I can find is in Pudd'nhead Wilson's New Calendar: "Faith is believing what you know ain't so." But that's not quite the same thing, is it?
In any event the sentiment of the aphorism we are talking about is certainly not original to Mark Twain. A few other people have been credited with the observation that there is more danger in our holding beliefs that aren't true than there is in outright ignorance. Better to be dumb than wrong.
No less a philosopher than Satchel Paige is said to have observed: It's not what you don't know that gets you into trouble, it's what you know that just ain't so that gets you into trouble." Too many "troubles" in that version to make for a good aphorism, so Satchel Paige strikes-out once again.
And speaking of baseball, Yogi Berra has also been credited with the remark. He's one of those people that it's easy to pin weird sayings on; you can credit him with some dumb remark and folks will go, "Yeah, that sounds like ol' Yogi, alright."
As far as INTENTIONALLY funny people (that is, not Yogi Berra), the "cowboy philosopher" Will Rogers is another reputed speaker of the line that got this started but, once again, nobody's been able to find the saying in any of his works.
A lesser-known humorist and semi-contemporary of Twain named Josh Billings (whose real name was Henry Wheeler Shaw, (what is it about humorists that makes 'em want to write under assumed names?)), is credited with saying "It's not ignorance does so much damage; it's knowin' so derned much that ain't so." Now EXACTLY those words have not been found in any of Billing's/Shaw's writings but similar ideas are in his 1874 book Everybody's Friend, or Josh Billling's Encyclopedia and Proverbial Philosophy of Wit and Humor, to whit: "I honestly believe it is better to know nothing than to know what ain't so." So... did one of them-Twain or Billings-borrow the idea from the other? Did they come up with it independently? Did each of 'em overhear it somewhere separately? Did they use the same joke book? I suppose we'll never know. And that's my point.
Maybe we'd be better off following the wisdom of Confucious: "To know is to know that you know nothing. That is the meaning of true knowledge." Or, before him, of Socrates: "True knowledge exists in knowing that you know nothing." What kind of world is this when even famous dead philosophers crib stuff from one another?
Somebody once said, "Good lines become great ones when presented as the utterances of those whom we already hold in high esteem for their wit." That somebody was Barbara Mikkelson, writing recently for Snopes.com. That I know. But I don't know where she got it.
UPDATE: Please see this more recent post.