I have no problem understanding what counts as "extraordinary claims": references to the "non-/extra-/supernatural" (basically everything that´s defined as being beyond human capabilities of investigation, of science etc.).
Another vote for 'extraordinary is not necessarily supernatural'.
My question: What would count as "extraordinary evidence"?
(And my thesis is: There isn´t and can´t be - per definition -such a thing as "extraordinary evidence". Thus, while I agree that we reject the idea that "ordinary" evidence is sufficient to support extraordinary claims, I don´t see much point in demanding "extraordinary evidence".)
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Now, would you guys agree that the quote is misapplied when we are facing claims regarding that which is a priori defined as "supernatural"?
It doesn't make as snappy a quote, but what I'm generally looking for in order to accept a belief is
sufficient evidence. (What counts as sufficient? Evidently, evidence that convinces me to accept the belief.)
Suppose you turn on the television at random and see a woman holding a microphone, while a news crawl runs along the bottom of the screen, and a giant network news logo is stamped in the corner of the screen.
"Here I am in London," she says, with the Parliament Building and Big Ben in the background.
Do I have enough evidence to believe her claim? Without the elaborate prefacing in this thread, I expect most of us would accept the claim tacitly while watching the video.
"Here I am deep inside Fort Knox," she says, with stacks of gold bars in the background.
Here, the background imagery may be less sufficient to cause us to accept her statement as factual. But suppose she introduces a uniformed personage...
"I'm standing here with the public relations officer of Fort Knox, more correctly known as the United States Bullion Depository."
I think that would be convincing for me.
"Here I am on the Moon," she says, with a giant luminous Earth hovering in the background. "I'm standing here with the public relations officer of the Moonbase, more correctly known as the Experimental Lunar Expeditionary Station."
I expect none of us would believe the claim. But suppose it were followed by a live transmission from the White House, where Obama "can finally reveal" the existence of the secret moonbase program. He drones on for a while, and then a filled press room full of people you vaguely recognize from the White House press corps start asking questions...
Different claims clearly require different amounts of evidence. And one of the conditions that sets the sufficiency bar is the mismatch (if any) between the believability of the claim and the fakability of the evidence.
It is just as easy to put a shot of London in the background of a picture, as it is to put Fort Knox. They are both easily and equally fakable. But we accept one without thinking, and the other may give us momentary pause, requiring additional reassurance that what we see is true.
I think another thing that enters into it is the strength of negative evidence. We know there is no moonbase, so we would have a hard time accepting that claim without... extraord... er,
sufficient evidence. In this case, the sufficiency bar is quite high.
We know that decades of research have shown that people can't call out
Zener cards any better than slightly above chance (at best) through psychic abilities. And that taking additional precautions in the testing reduced even the best card-callers performance back to chance.
If we saw some ordinary evidence (a video on TV) of a foreign spelling bee in which a contestant spelled 25 words in a row and we were told it was done correctly, we should be inclined (I think) to believe that these words were indeed spelled correctly.
If we saw some ordinary evidence (a video on TV) of someone calling out 25 Zener cards in a row (and we knew something about these tests of 'ESP'), we wouldn't believe it.
The weight of all the previous evidence makes the claim extraordinary, and so we require extraor... sufficient evidence before believing it.
I think it's possible for there to be a sufficient amount of ordinary evidence to establish the claim well enough to justify tentative belief.
We strip the psychic naked, and hire James Randi and the ghost of Carl Sagan to oversee the testing, with cameras everywhere, quadruple blinds, and the cards are in a different room somewhere else on earth, locked in a time vault. The psychic writes down 25 cards in a row, and his guesses are broadcast to the world before the cards are examined. So on and so forth. There's nothing supernatural about the new conditions, but they certainly seem extraordinary, in the usual sense.
If he passed with flying colors, I can't think of any reason not to accept his claim. (And then burn him as a mutant/witch, of course.)
So while the true threshold for belief is
sufficient evidence, I think there are cases where this calls for extraordinary measures to be taken. If this gets boiled down into a snappy saying suitable for meme-ification, I can live with that.
