"Extraordinary Claims Require Extraordinary Proof" (Meaning & Implications)

[MrRING]

I came across this phrase recently in a non-paranormal scientific program about paleolithic digs and the possibility that some of the remains of mastodon were actually "meat-caches" left by humans previous to the time when humanity was supposed to be in the Americas (very pre-"Clovis"). In any case, it got me to wondering about simply the concept of extraordinary claims require extraordinary proof, aside from any skeptical or believer baggage.

Is the phrase "Extraordinary Claims Require Extraordinary Proof" actually a technical phrase used in science textbooks? Or is it a non-scientific phrase that is just a popular colloquialism but not really used by the scientific establishment?

I would think that, in science, proof either is or is not, so that to practical scientists there is no difference between proof or extraordinary proof, so I fall into the idea that ECREP is just a popular colloquialism.

 

[gordonrutter]

I've never come across it in all my science work. Wikipedia tells us

"Extraordinary claims"

An extraordinary claim requires extraordinary proof.

— Marcello Truzzi, On the Extraordinary: An Attempt at Clarification, Zetetic Scholar, Vol. 1, No. 1, p. 11, 1978

Carl Sagan popularized this as "Extraordinary claims require extraordinary evidence".[15] However, this may have been based on a quote by Laplace which goes, "The weight of evidence for an extraordinary claim must be proportioned to its strangeness." This, in turn, may have been based on the statement "A wise man, therefore, proportions his belief to the evidence" by David Hume.

But even though Laplace was a mathematician and astronomer this particular phrase has never entered mainstream science as far as I'm aware. Just the skeptics.

Gordon

 

[Xanatic_]

It's not a phrase used in science textbooks, but the idea of it is.

 

[Cochise]

I thought 'proof' was an absolute, in scientific terms. As opposed to 'evidence'.

Although I seem to recall some effort recently to redefine a theory with 'strong evidence' as 'proven'. Some people cannot live with even the tiniest hint of uncertainty.

 

[Xanatic_]

Well the original quote from Sagan used the word evidence.

As for not being able to deal with uncertainty, I'd say it's more about being unable to stomach creationists who will say evolution is "only a theory" while misunderstanding the whole concept of scientific theory.

 

[Spookdaddy]

From a kind of poetic point of view, I've always taken this to be a simple matter of fact: I mean, if something is so extraordinary, then the proof of it will be extraordinary; doesn't matter if that proof is glaringly simple, or incredibly complex.

If you're ever in a situation where you are inspired to say, 'Wow, my god, this leads to that' - then extraordinary is kind of implied in both the this and the that.

Or is that just me?

 

[Xanatic_]

I'd say you've misunderstood the meaning of the word extraordinary. It doesn't mean "awesome" or "really cool".

 

[Spookdaddy]

I'd say you've misunderstood the meaning of the word extraordinary. It doesn't mean "awesome" or "really cool".

Oh no, I understand it - I just make a better poet than I do a scientist.

 

[MrRING]

Thanks for bringing up poetry; it makes me think that the statement of extraordinary claims could be considered a truism...

http://en.wikipedia.org/wiki/Truism

A truism is a claim that is so obvious or self-evident as to be hardly worth mentioning, except as a reminder or as a rhetorical or literary device and is the opposite of falsism.[1]

In philosophy, a sentence which asserts incomplete truth conditions for a proposition may be regarded as a truism. An example of such a sentence would be: "Under appropriate conditions, the sun rises." Without contextual support – a statement of what those appropriate conditions are – the sentence is true but incontestable. A statement which is true by definition ("All cats are mammals.") would also be considered a truism. This is quite similar to a tautology in which the conclusion of a statement is essentially equivalent to its premise, a statement that is "true by virtue of its logical form alone".[2]

The word may be used to disguise the fact that a proposition is really just an opinion, especially in rhetoric. A saying about people or an accepted truth about life in general is also a truism.

 

[Cochise]

Well the original quote from Sagan used the word evidence.

As for not being able to deal with uncertainty, I'd say it's more about being unable to stomach creationists who will say evolution is "only a theory" while misunderstanding the whole concept of scientific theory.

I understand the frustration, but distorting the language for populist reasons will only lead to yet more sniping because people will simply focus on the areas where the theory does still need completeness and use that to devalue any reasonably well supported scientific theory.

If people don't understand science there is little you can do with them. Better education is the only answer.

I'm still not happy with the original quote, though, because one item of incontrovertible evidence may in fact constitute proof. You could argue that the behavior of water when it freezes is extraordinary, but we know it behaves that way - er - 'cos it does. It's unlikely that if water was a fabulously rare substance that people would believe that it behaves the way it does.

 

[Spookdaddy]

I'd say you've misunderstood the meaning of the word extraordinary. It doesn't mean "awesome" or "really cool".

Oh no, I understand it - I just make a better poet than I do a scientist.

(And neither does 'awesome', for that matter.)

 

[Xanatic_]

I meant awesome in the colloquial sense.

Cochise: Yes, water freezing is a common, ordinary thing which is why people don't tend to ask for much in the way of evidence for a lake in Norway having frozen. However water does under some circumstances exhibit some quite extraordinary qualities, and in those cases the scientists investigating it do need pretty good evidence for it. Which is why it involves repeated experimentation, peer-review and such things. If the evidence is good enough, it then becomes accepted that yes, water does turn purple when elephants bathe in it. Or whichever particular thing is claimed about water.

 

[Cochise]

I meant awesome in the colloquial sense.

Cochise: Yes, water freezing is a common, ordinary thing which is why people don't tend to ask for much in the way of evidence for a lake in Norway having frozen. However water does under some circumstances exhibit some quite extraordinary qualities, and in those cases the scientists investigating it do need pretty good evidence for it. Which is why it involves repeated experimentation, peer-review and such things. If the evidence is good enough, it then becomes accepted that yes, water does turn purple when elephants bathe in it. Or whichever particular thing is claimed about water.

What I meant was that water expands when it freezes. Most other substances shrink when they become solid. It is extra-ordinary behaviour, despite being something we are very familiar with.

 

[Xanatic_]

Yes, but quite a quick and simple thing to prove as well. Water also has other interesting qualities, some of which we are learning about just now. Those are the ones that go through peer-review etc.

I would say the word extraordinary can best be described as how far it is from what we already know.

 

[dreeness]

All claims are "extra-ordinary", unless and until they are proven, then they become just ordinary. Something new is claimed, and because it is a new claim it is beyond the ordinary.

ECREP (which btw Truzzi eventually disowned) in practice is really just a glib justification for endless goalpost-moving, if something you would rather not be true is being claimed, no amount of proof will ever be sufficiently "extraordinary".



Some guy claims he has taught a squirrel to play a toy piano.

Prove it!

-- Okay, here's a film of the squirrel tapping out a simple version of "Mary Had A Little Lamb".

Ha! That's just random chance, you probably had to film that squirrel non-stop for months or even years before you got a sequence of notes that approximated that song!

-- Okay, here's a film of the same squirrel doing a jazz version of "Mary Had A Little Lamb".

Ha! Just a sequence of actions, learned by rote! That squirrel isn't really "playing" anything!


(fifty years later)


Ha! This so-called "opera" written and performed by squirrels is entirely derivative of Wagner, except with hazelnuts instead of gold.

 

[MrRING]

So we've all heard the aphorism extraordinary claims require extraordinary proof (or evidence, depending on the speaker). But like another famous phrase "if thou gaze long into an abyss, the abyss will also gaze into thee", I began to wonder about the veracity of this claim as a statement. Is there truly a scientific standard for extraordinary proof, versus standard proof, as in what is the exact process to determine when proof expands exponentially to become extraordinary proof? I've got a feeling that this long-cherished statement by skeptics is actually built on something that doesn't exist, and can't exist, because once something is proven, it is proven.

 

[EnolaGaia]

NOTE: Newest post merged into existing thread on the subject of extraordinary claims / proofs. Thread re-titled and moved to General Forteana.

 

[EnolaGaia]

... This, in turn, may have been based on the statement "A wise man, therefore, proportions his belief to the evidence" by David Hume. ...

This other quote from Hume more directly addresses the sort of criteria at issue:

"No testimony is sufficient to establish a miracle, unless the testimony be of such a kind, that its falsehood would be more miraculous than the fact which it endeavors to establish."

Hume, David (1748). An Enquiry concerning Human Understanding.
(https://davidhume.org/texts/e/10)

SOURCE: https://rationalwiki.org/wiki/Extraordinary_claims_require_extraordinary_evidence#cite_ref-2

 

[Yossarian]

In essence, it's about the burden of proof, more than it's about the evidence itself.

It's not particularly scientific, but mundane proof/a mundane explanation would likely be sufficient for a mundane claim, less so for an extraordinary one.

If my kid told me, "I know my friend's Dad can drive, because I've seen him driving", I would probably accept that eye witness testimony as proof. If he told me, "I know my friend's Dad can fly, because I saw him soar past the window", eye witness testimony isn't really enough.

Basically, the odder the claim, the more substantial the evidence required for it to pass muster, the more mundane the claim, the more we're likely to accept circumstantial evidence.

 

[MrRING]

Hilarious – the thread already existed… and I made it! I did try to find it, honest guv.

 

[EnolaGaia]

The phrasing most often encountered is Truzzi's, which cites "proof" rather than "evidence" (Laplace; Sagan) or "testimony" (Hume).

The semantic difference between "proof" and "evidence" is critical here, because focusing on Truzzi's phrasing ("proof" rather than "evidence") obscures certain subtleties in the earlier, more seminal, texts.

To complicate matters, the semantics associated with "proof" in today's colloquial speech don't necessarily align with (e.g.) Hume's allusions to "proof" in the text cited / linked above. Nowadays we commonly use "prove" to connote "demonstrate beyond any doubt", whereas in earlier usage it didn't necessarily connote anything more than "maintaining acceptable coherence / viability even after scrutiny / testing."

 

[EnolaGaia]

Hilarious – the thread already existed… and I made it! I did try to find it, honest guv.

Don't fret ... There's no corollary maxim asserting "extraordinary posting missteps require extraordinary excuses."

 

[EnolaGaia]

Now back to the questions posed in MrRING's most recent post ...

... Is there truly a scientific standard for extraordinary proof, versus standard proof, as in what is the exact process to determine when proof expands exponentially to become extraordinary proof?

The short answer to the first part is "No - there's no scientific standard relating to extraordinariness."

In the context of scientific method, the degree of miraculousness inherent in or attributed to a hypothesis is effectively a peripheral gloss that carries no weight.

This is not to say that a novel claim cannot or will not demand more extensive (rigorous; precise; comprehensive, etc.) evidence and analysis to be accepted. It is in this sense of additional / beyond-past-limits scope (of evidence gathering / analysis) that allusion to anything "extraordinary" reasonably applies.

... I've got a feeling that this long-cherished statement by skeptics is actually built on something that doesn't exist, and can't exist, because once something is proven, it is proven.

I would say that the thing that doesn't exist (in the context of scientific method) is the notion that "... once something is proven, it is proven."

In part this results from the semantics of "prove / proof" noted above. More importantly, this results from the fact the scientific method is and always has been a procedural model for formulating, testing, and refining the most defensible - not necessarily any absolute or final - explanation for the phenomena at issue.

It only requires one compelling experiment or demonstration to overturn a theory, regardless of how many previous incidents attested to its "truth".

 

[Yithian]

Cf. Quod gratis asseritur, gratis negatur.

More recently recoined as 'Hitchens' Razor':

What can be asserted without evidence can be dismissed without evidence.

https://en.m.wikipedia.org/wiki/Hitchens's_razor

 

[feinman]

Just because claims might be extraordinary and a level of evidence isn't available that would convince others, it doesn't mean they aren't true. if before cameras someone sighted a pirate ship, or later a U-boat and told others about it, but only had personal accounts which all matched up, it doesn't mean that a pirate ship or U-boat wasn't sighted. I've often thought how vulnerable we would be to a sneak attack from elsewhere; skeptics would still want that laboratory-testable evidence, ignoring accounts from pilots, folks in the military, doctors and lawyers and such, and then boom. Real Independence Day movie, bunch of people arguing about UFOs, and then --boom, we're gone before skeptics are able to assimilate things into their paradigm.

 

[GNC]

Hmm, not sure of your analogy, because pirate ships were experienced by plenty of people (including the pirates) and have lots of human accounts to back them up since they were a human phenomenon. UFOs on the other hand have plenty of reasons not to exist that the pirate ships do not, in fact humanity being what it is, a world without someone trying to take advantage of you is almost 100% less likely than a world regularly (or even once) visited by space aliens. I don't know about extraordinary proof, but extraordinary claims do need to be very robust - not to say they're never proven, of course, but it's a lot more complicated than a simple yay or nay.

 

[feinman]

Hmm, not sure of your analogy, because pirate ships were experienced by plenty of people (including the pirates) and have lots of human accounts to back them up since they were a human phenomenon. UFOs on the other hand have plenty of reasons not to exist that the pirate ships do not, in fact humanity being what it is, a world without someone trying to take advantage of you is almost 100% less likely than a world regularly (or even once) visited by space aliens. I don't know about extraordinary proof, but extraordinary claims do need to be very robust - not to say they're never proven, of course, but it's a lot more complicated than a simple yay or nay.

I guess I am just describing cases before there were photographs or other data gathering devices; for a very long time human accounts were relied upon; true there was concensus that pirate ships were around and U-boats, but if one turned up and then took off, all you would have were the accounts of those who viewed it --perhaps all matching accounts, If more than one person saw them and were trustworthy witnesses, they would possibly be believed --now we seem to discount witnesses, no matter their background, and invoke things like the psychosocial hypothesis to tell them they are mistaken. Then the U-boat turns up and torpedoes the ship..

Agreed, though, the analogy is a bit weak!

 

[GNC]

Agreed, though, the analogy is a bit weak!

Don't worry about it, I was trying to concoct an analogy myself and struggled to find one that was apt enough. I suppose you could look to religious visions from the past, as later in the 20th century UFOs took over from them as a phenomenon that science was unsure of, but faith would accept, often without question. Is that any better? Anyone is welcome to jump in with their own theory here!

 

[Mikefule]

The Carl Sagan version of the expression is probably the best known.

I used to cite it when I was giving training and coaching in an insurance fraud investigation team. In that context, the word "claim" had a different resonance.

Examples:
"I had a watch stolen. I'd had it a few years. I guess it was worth £50 or so."
"OK, I can't see any problem with that. I can pay you £50."

"I had a Rolex watch stolen. It was worth £20,000. I can't remember how long ago I bought it."
"OK, I need to see as many as possible of the following: receipt, warranty, manual, certificate of authenticity, details of where you had it serviced, evidence that it's been listed on the Rolex Lost and Stolen Register, and photos of you wearing it."
"I don't have any of that. All my paperwork and photos were destroyed in a house fire years ago."
"OK. I want the address where the fire occurred, and the approximate date of the fire. Which insurance company dealt with the insurance claim? I'll need to speak to them. I'll also need to check news reports for the date in question and seek a report from the Fire Service that attended..."



The problem with the "Sagan principle", as others have highlighted, is the ambiguity over the meaning of "extraordinary".

Indeed, it is not a good example of a logical or rational maxim, partly because one important word — extraordinary — has two different meanings in one short sentence. In a different context, such as politics or sales, or a row with partner, shifting the meaning of a key word as an argument progresses is a common, and dishonest tactic.


I think what any scientist would say is something like:

An extraordinary claim is a claim (theory, hypothesis, report, observation, etc.) that at first sight is inconsistent with the dominant and paradigm.

Example: The effects of gravity have been observed, measured, and mathematically defined. Gravity is understood to apply consistently and predictably on the surface of the Earth. A claim of levitation, or of an antigravity device is an extraordinary one.

Extraordinary evidence is simply a higher level of evidence than might be considered acceptable if the new idea was broadly consistent with the paradigm.


You might think that a good scientist would require a consistent level of evidence for any new hypothesis, rather than requiring additional evidence simply because an idea was unusual. However, it is fair to say that sufficient evidence would be required to overcome objections arising from any apparent inconsistency with the well established and understood orthodoxy.

In normal life, we tend to require more evidence if something is unexpected, and particularly if it is more serious.

 

[Sharon Hill]

A complimentary example: Someone says they were abducted by aliens. :abduct:

That is an extraordinary claim because I would have to reject much well-established knowledge that is based on very strong evidence such as how physics operates and the likelihood of non-human but humanoid beings making contact with people. Having a story or a blurry photo is not worth anything. The bar is so much higher.

[When people think one photo will "prove" this :ness: or that :bf:--> ]