It’s a quote first said, as near as I can tell, by Carl Sagan, and repeated by nearly every noteworthy skeptic who has followed in his footsteps:
“Extraordinary claims require extraordinary evidence.”
I’m conflicted about it.
On the face of it, I think it’s a great quote, and one I wholeheartedly agree with.
But it’s also a quote that leaves itself dangerously open to interpretation when read outside of context, as quotes often are, especially on the open internet.
Let me explain.
For the skepticism advocate, the meaning of the quote is clear. You make a big claim, you better have the evidence to back it up.
And it doesn’t matter if that claim is about God or ghosts or UFOs or 9/11 being an inside job or Nigerian princes who just need a little help with a minor financial transaction.
You make a big claim, you better have the evidence to back it up.
So what’s the problem?
As it happens, I’ve spoken with many believers who interpret the quote as skeptics saying there are two different types of claims, and two different types of evidence.
There’s your normal, everyday claim, and then there are claims that are somehow special — extraordinary.
Likewise, there is normal, everyday evidence, which is sufficient to satisfy the burden of proof for a normal, everyday claim — but which is not sufficient evidence for an extraordinary claim.
So far, the skeptic may even be inclined to agree with this assessment. The claim, “I had a chicken sandwich for lunch,” might be an example of an ordinary claim. Whereas “I slew a dragon last night before dinner,” might be an example of an extraordinary claim.
One of these claims is likely to be believed with little verifying evidence, and the other is not.
But the believer goes on to say that the sorting of claims into the categories ordinary or extraordinary is purely arbitrary.
The skeptic, they say, is filing away any claims that don’t fit their worldview into a shoebox labeled extraordinary, and then applying an unfair standard of evidence to them — while holding all other claims to a much easier-to-satisfy standard.
That’s not what the skeptic is doing, but it’s easy to understand why the quote might be interpreted that way, especially if you’re already coming from the perspective that skeptics are being obstinate in their incredulity. Put those two things together and you’ve got a natural inclination to misread the quote.
The truth is, there is no such thing as ordinary evidence and extraordinary evidence. There’s just evidence.
It’s just that an ordinary claim is one that we already have a preponderance of evidence for, and we just don’t tend think about it so much.
Let’s go back to my earlier hypotheticals.
“I had a chicken sandwich for lunch.”
“I slew a dragon before dinner last night.”
Now let’s unpack those.
The first claim presupposes a couple of things.
(1) That chickens exist, and (2) that they are edible.
The evidence for the existence of chickens, and that they are a common food source, is readily available and widely agreed upon. That’s why you’re likely to take someone’s word for it when they tell you they had a chicken sandwich for lunch. That’s what makes it an ordinary claim.
An extraordinary claim is one for which we don’t have that established, baseline evidence. A claim, for example, about the existence of dragons.
I realize that these ideas may sound obvious, and that as a result this whole diatribe might be coming off as condescending and patronizing.
But you might be surprised how many people you’ll meet who will argue the point. People who either don’t see the distinction, or who will claim they don’t see the distinction, because recognizing the distinction presents a threat to their belief system.