Sagan’s “extraordinary claims require extraordinary evidence” is nonsense. Here’s why

[Rramjet]

I have distilled the following discussion from another thread because I feel it is important enough to deserve a thread of its own.

Originally Posted by leon_heller

…Basically, it's a case of "extraordinary claims require extraordinary evidence".

Originally Posted by Rramjet

…The particular phrase quoted above is perhaps one of the most frequently promulgated pieces of woo within skeptical discussion. Precisely what is "extraordinary evidence"? Evidence is evidence. You either have it or you do not. Until anyone can actually define "extraordinary evidence" - and critically, provide an example of it - the phrase will remain nonsensical.

Of course the phrase has a certain emotional appeal, but such an appeal has no place in critical thinking, logic, or scientific discussion.

Originally Posted by paximperium

I consider Extraordinary Evidence to be either conclusive irrefutable evidence(such as finding an asteroid or an alien) or series of evidence that is superior to the evidence against the claim.

But I agree. I'd be happy to start with just good evidence.

Yes, you’re getting close, but strictly speaking there is also no such thing as “good” (or “bad”) evidence either. Evidence is evidence. You either have it or you do not. The preceding adjectives (“extraordinary”, “good”, etc), especially without context, are subjective and emotive value judgements that should have no place in true sceptical debate (with the implied constraints of conforming to the strict standards of critical thinking, logic and science).

Originally Posted by leon_heller

I heard Richard Dawkins say it on TV a couple of evenings ago, in a programme about woo.

Originally Posted by paximperium

It's by Carl Sagan.

“Sagan is also widely regarded as a freethinker or skeptic; one of his most famous quotations, in Cosmos, was, "Extraordinary claims require extraordinary evidence."[40] This was based on a nearly identical statement by fellow founder of the Committee for the Scientific Investigation of Claims of the Paranormal, Marcello Truzzi, "Extraordinary claims require extraordinary proof."[41] This idea originated with Pierre-Simon Laplace (1749–1827), a French mathematician and astronomer who said, "The weight of evidence for an extraordinary claim must be proportioned to its strangeness."[42]” (http://en.wikipedia.org/wiki/Carl_Sagan)

Originally Posted by leon_heller

I was in good company, then, with both Dawkins and Sagan saying it. Rramjet's view that it's "woo" looks like nonsense.

Like a game of Chinese whispers, the true meaning of the message becomes distorted over time to end in complete nonsense. That is, LaPlace’s sensible “weight of evidence” becomes in Sagan’s hands the nonsensical phrase “extraordinary evidence”.

…and no matter the “eminence” of the person stating it, it remains nonsensical.

We should thus, as ever, be forewarned about simply accepting without critical thought received “wisdom”. All is often rarely what it seems.

Originally Posted by Alan

What "extraordinary evidence" means to me is evidence sufficient in quantity/quality to overcome what makes it an extraordinary claim (which is the evidence against it).

Regular evidence can count, but a lot of that (= an "extraordinary" amount) would be needed as appropriate to counter the evidence against it.

Yes, you are describing Laplace’s “weight of evidence”, but critically, an “extraordinary amount” of evidence does not make the evidence itself “extraordinary”.

Originally Posted by fls

I think that it is a mistake to repeat this quote ("extraordinary claims require extraordinary evidence")' because the people at which it is aimed do not understand what it means.
Linda

The “people at which it is aimed” do not understand it in equal proportion to the people who state it – because it is nonsense dressed up as wisdom.

Originally Posted by fls

It sounds like sScientists are cheating by raising the bar only for those claims they are biased against.

Corrected that for you… (but ‘scientists” can be forgiven, for they simply do not understand what they say).

Originally Posted by fls

[And since that isn't the case, all we have managed to do with this catchy-sounding phrase is to embroil ourselves in attempts to defend ourselves against people like Rodney, who quite correctly are able to recognize that we should not make a distinction a priori between ordinary and extraordinary claims.

Precisely.

I believe therefore, that when anyone who considers themselves to be a true sceptic is tempted to refer back to Sagan’s nonsensical statement containing the phrase “extraordinary evidence”, they should actually refer back to LaPlace and quote his statement (eg here: http://www.todayinsci.com/L/Laplace_...Quotations.htm) containing his eminently accurate and sensible phrase "weight of evidence”.

Of course one can paraphrase LaPlace if one considers his language too archaic for a modern audience. One can also include Sagan in such a paraphrase to get the best of both worlds! Thus:

To paraphrase both Sagan and LaPlace: Extraordinary claims require a greater weight of evidence.

Now we can argue over whether that contention itself actually has rational meaning…

As fls points out, the adjective “extraordinary” in “extraordinary claims” is itself a post hoc rationalisation.

Surely a claim is made and supporting or contrary evidence is put forward by the debating parties.

How can we know a priori that a claim is “extraordinary? After examination of the “weight of evidence”, what if it turns out to be a true claim? Surely then the claim becomes, by definition, “ordinary”. The point is, one simply cannot make the a priori value judgement.

…and of course if Sagan’s statement ( "extraordinary claims require extraordinary evidence"”) was not already shown to be nonsense, this puts the final nail in the coffin.

Quite simply, the veracity of any claim must be assessed according to the “weight of evidence”. It is only after such an assessment that we might consider using adjectives to describe either the claim or the evidence – and that only if we no longer consider ourselves to be true sceptics!

[Resume]

Somewhere in that wall of straw, you typed "evidence is evidence." I quite agree.

When some credible evidence is offered for, say, alien spacecraft visiting our blue planet, one is helpless but to examine it. Credible, able to withstand scrutiny; not extraordinary, but credible. Not photos of tossed hubcaps. Not blimps. No special pleading for that evidence either.

[tsig]

Originally Posted by Rramjet

I have distilled the following discussion from another thread because I feel it is important enough to deserve a thread of its own.






Yes, you’re getting close, but strictly speaking there is also no such thing as “good” (or “bad”) evidence either. Evidence is evidence. You either have it or you do not. The preceding adjectives (“extraordinary”, “good”, etc), especially without context, are subjective and emotive value judgements that should have no place in true sceptical debate (with the implied constraints of conforming to the strict standards of critical thinking, logic and science).



“Sagan is also widely regarded as a freethinker or skeptic; one of his most famous quotations, in Cosmos, was, "Extraordinary claims require extraordinary evidence."[40] This was based on a nearly identical statement by fellow founder of the Committee for the Scientific Investigation of Claims of the Paranormal, Marcello Truzzi, "Extraordinary claims require extraordinary proof."[41] This idea originated with Pierre-Simon Laplace (1749–1827), a French mathematician and astronomer who said, "The weight of evidence for an extraordinary claim must be proportioned to its strangeness."[42]” (http://en.wikipedia.org/wiki/Carl_Sagan)


Like a game of Chinese whispers, the true meaning of the message becomes distorted over time to end in complete nonsense. That is, LaPlace’s sensible “weight of evidence” becomes in Sagan’s hands the nonsensical phrase “extraordinary evidence”.

…and no matter the “eminence” of the person stating it, it remains nonsensical.

We should thus, as ever, be forewarned about simply accepting without critical thought received “wisdom”. All is often rarely what it seems.


Yes, you are describing Laplace’s “weight of evidence”, but critically, an “extraordinary amount” of evidence does not make the evidence itself “extraordinary”.


The “people at which it is aimed” do not understand it in equal proportion to the people who state it – because it is nonsense dressed up as wisdom.


Corrected that for you… (but ‘scientists” can be forgiven, for they simply do not understand what they say).


Precisely.

I believe therefore, that when anyone who considers themselves to be a true sceptic is tempted to refer back to Sagan’s nonsensical statement containing the phrase “extraordinary evidence”, they should actually refer back to LaPlace and quote his statement (eg here: http://www.todayinsci.com/L/Laplace_...Quotations.htm) containing his eminently accurate and sensible phrase "weight of evidence”.

Of course one can paraphrase LaPlace if one considers his language too archaic for a modern audience. One can also include Sagan in such a paraphrase to get the best of both worlds! Thus:

To paraphrase both Sagan and LaPlace: Extraordinary claims require a greater weight of evidence.

Now we can argue over whether that contention itself actually has rational meaning…

As fls points out, the adjective “extraordinary” in “extraordinary claims” is itself a post hoc rationalisation.

Surely a claim is made and supporting or contrary evidence is put forward by the debating parties.

How can we know a priori that a claim is “extraordinary? After examination of the “weight of evidence”, what if it turns out to be a true claim? Surely then the claim becomes, by definition, “ordinary”. The point is, one simply cannot make the a priori value judgement.

…and of course if Sagan’s statement ( "extraordinary claims require extraordinary evidence"”) was not already shown to be nonsense, this puts the final nail in the coffin.

Quite simply, the veracity of any claim must be assessed according to the “weight of evidence”. It is only after such an assessment that we might consider using adjectives to describe either the claim or the evidence – and that only if we no longer consider ourselves to be true sceptics!

You're trying to get anecdotes in as evidence aren't you?

[William Parcher]

Originally Posted by Rramjet

Evidence is evidence.

Counterfeiters want you to think that money is money.

[Resume]

Originally Posted by tsig

You're trying to get anecdotes in as evidence aren't you?

I'm fairly sure that's the point of all this.

[ThunderChunky]

Ordinary claim: This is a cup of coffee.
Extraordinary claim: This is a magical cup of coffee.

I am going to require different levels of evidence to believe these two claims. The ordinary claim I may believe just on the look and smell alone. The extraordinary claim will require more evidence--extraordinary evidence. I will need to observe evidence of the extraordinary nature of the claim. Just looking and smelling like coffee is not enough.

Ordinary claim: I went to taco bell for lunch.
Extraordinary claim: I ate lunch on the moon.

I will believe the first claim in most cases just on someones word because it's quite ordinary. The second claim will require more evidence.

[Slimething]

As most of the posters above, I believe you're misinterpreting Sagan's line. I believe, but cannot prove, that he meant that an extraordinary claim must be matched with specific, irrefutable evidence that also matches the quality of the claim.

For example, someone can say "I can cure your hunger." and offers you a sandwich. That's pretty good evidence. However, if the claim was "I can solve world hunger", the sandwich doesn't quite cut it.

[John Jones]

Nice try.

Better luck next time.

[joobz]

Originally Posted by Rramjet

I have distilled the following discussion from another thread because I feel it is important enough to deserve a thread of its own.


Yes, you’re getting close, but strictly speaking there is also no such thing as “good” (or “bad”) evidence either. Evidence is evidence. You either have it or you do not. The preceding adjectives (“extraordinary”, “good”, etc), especially without context, are subjective and emotive value judgements that should have no place in true sceptical debate (with the implied constraints of conforming to the strict standards of critical thinking, logic and science).



“Sagan is also widely regarded as a freethinker or skeptic; one of his most famous quotations, in Cosmos, was, "Extraordinary claims require extraordinary evidence."[40]
[snip]
Quite simply, the veracity of any claim must be assessed according to the “weight of evidence”. It is only after such an assessment that we might consider using adjectives to describe either the claim or the evidence – and that only if we no longer consider ourselves to be true sceptics!

Here's an example of a pendantry gone wrong.
"Extraordinary claims require extraordinary evidence." =
"Extraordinary claims require more evidence than non-extraordinary claims".

[RoboTimbo]

Santa Claus lives at the North Pole and delivers presents to all the good little boys and girls on Christmas eve.

Rramjet, is that an ordinary claim or is it extraordinary?

[fromdownunder]

*sigh*, Roger,

1. I had bacon and eggs for breakfast
2, I had bacon and eggs for breakfast at The Restaraunt at the End of The Universe.

I could show you a photo of a plate of bacon and eggs, with me next to it, or even shovelling a bit of bacon into my mouth. I could even photoshop a picture of an alien standing next to me while shovelling a bit of bacon into my mouth

Would you accept Statment 2 as accurate in either of these examples? Which one is the more likely statement, and why do you think (if you do) that I need more evidence for statement 2 than statement 1.

Norm

[tsig]

Originally Posted by fromdownunder

*sigh*, Roger,

1. I had bacon and eggs for breakfast
2, I had bacon and eggs for breakfast at The Restaraunt at the End of The Universe.

I could show you a photo of a plate of bacon and eggs, with me next to it, or even shovelling a bit of bacon into my mouth. I could even photoshop a picture of an alien standing next to me while shovelling a bit of bacon into my mouth

Would you accept Statment 2 as accurate in either of these examples? Which one is the more likely statement, and why do you think (if you do) that I need more evidence for statement 2 than statement 1.

Norm

If you told him you were abducted by aliens and then taken to the Restaurant then he'd go with 2.

[John Jones]

Originally Posted by Rramjet

I have distilled the following discussion from another thread because I feel it is important enough to deserve a thread of its own.






Yes, you’re getting close, but strictly speaking there is also no such thing as “good” (or “bad”) evidence either. Evidence is evidence. You either have it or you do not. The preceding adjectives (“extraordinary”, “good”, etc), especially without context, are subjective and emotive value judgements that should have no place in true sceptical debate (with the implied constraints of conforming to the strict standards of critical thinking, logic and science).



“Sagan is also widely regarded as a freethinker or skeptic; one of his most famous quotations, in Cosmos, was, "Extraordinary claims require extraordinary evidence."[40] This was based on a nearly identical statement by fellow founder of the Committee for the Scientific Investigation of Claims of the Paranormal, Marcello Truzzi, "Extraordinary claims require extraordinary proof."[41] This idea originated with Pierre-Simon Laplace (1749–1827), a French mathematician and astronomer who said, "The weight of evidence for an extraordinary claim must be proportioned to its strangeness."[42]” (http://en.wikipedia.org/wiki/Carl_Sagan)


Like a game of Chinese whispers, the true meaning of the message becomes distorted over time to end in complete nonsense. That is, LaPlace’s sensible “weight of evidence” becomes in Sagan’s hands the nonsensical phrase “extraordinary evidence”.

…and no matter the “eminence” of the person stating it, it remains nonsensical.

We should thus, as ever, be forewarned about simply accepting without critical thought received “wisdom”. All is often rarely what it seems.


Yes, you are describing Laplace’s “weight of evidence”, but critically, an “extraordinary amount” of evidence does not make the evidence itself “extraordinary”.


The “people at which it is aimed” do not understand it in equal proportion to the people who state it – because it is nonsense dressed up as wisdom.


Corrected that for you… (but ‘scientists” can be forgiven, for they simply do not understand what they say).


Precisely.

I believe therefore, that when anyone who considers themselves to be a true sceptic is tempted to refer back to Sagan’s nonsensical statement containing the phrase “extraordinary evidence”, they should actually refer back to LaPlace and quote his statement (eg here: http://www.todayinsci.com/L/Laplace_...Quotations.htm) containing his eminently accurate and sensible phrase "weight of evidence”.

Of course one can paraphrase LaPlace if one considers his language too archaic for a modern audience. One can also include Sagan in such a paraphrase to get the best of both worlds! Thus:

To paraphrase both Sagan and LaPlace: Extraordinary claims require a greater weight of evidence.

Now we can argue over whether that contention itself actually has rational meaning…

As fls points out, the adjective “extraordinary” in “extraordinary claims” is itself a post hoc rationalisation.

Surely a claim is made and supporting or contrary evidence is put forward by the debating parties.

How can we know a priori that a claim is “extraordinary? After examination of the “weight of evidence”, what if it turns out to be a true claim? Surely then the claim becomes, by definition, “ordinary”. The point is, one simply cannot make the a priori value judgement.

…and of course if Sagan’s statement ( "extraordinary claims require extraordinary evidence"”) was not already shown to be nonsense, this puts the final nail in the coffin.

Quite simply, the veracity of any claim must be assessed according to the “weight of evidence”. It is only after such an assessment that we might consider using adjectives to describe either the claim or the evidence – and that only if we no longer consider ourselves to be true sceptics!

Can you be more verbose/specific?

[Fnord]

Originally Posted by joobz

Here's an example of a pendantry gone wrong.
"Extraordinary claims require extraordinary evidence." =
"Extraordinary claims require more evidence than non-extraordinary claims".

Let me give it a try:

1a. More than <something> is extra-<something>.
1b. More than ordinary is extra-ordinary.

2a. Ordinary evidence is sufficient only for ordinary claims.
2b. Extra-ordinary evidence is sufficient only for extra-ordinary claims

::a. Ordinary evidence is required for ordinary claims.
::b. Extra-ordinary evidence is required for extra-ordinary claims.

I know that this must violate some rules regarding syllogistic reasoning, and may run afoul of equivocation, as well. But there may be another reader who is more skilled in this type of thinking to present the idea in a way that is both clear and concise to even the most deluded among us.

For the record, I also think that the OP is trying to make a case for allowing unsupported anecdotes {fantasies, ideas, legends, myths, opinions, rumors, et cetera} to be admissable as evidence.

[Patricio Elicer]

Originally Posted by Rramjet

How can we know a priori that a claim is “extraordinary? After examination of the “weight of evidence”, what if it turns out to be a true claim? Surely then the claim becomes, by definition, “ordinary”. The point is, one simply cannot make the a priori value judgement.

We cannot know that a claim is extraordinary, but we can make a judgement that it is.

We can judge a claim to be extraordinary when, if true, it would revolutionize our knowledge of the natural world and/or oblige us to modify the laws of physics that have been experimentaly corroborated over and over again for centuries.

So, please answer this: if I say that I can move physical objects solely with the power of my mind, is it ordinary or extraordinary claim?

[Rramjet]

Originally Posted by ThunderChunky

Ordinary claim: This is a cup of coffee.
Extraordinary claim: This is a magical cup of coffee.

What makes “This is a magical cup of coffee” an extraordinary claim? Could it be perchance that you are applying a post hoc rationalisation according to a particular belief of yours (based on examination of the evidence of course…) that “There are no such things as magical cups of coffee”?

However, when a claim is made, how can you a priori decide if the claim is “extraordinary” or not. Of course you cannot – you have to wait until after the evidence is examined to make that judgement call. That is why a general statement that requires “extraordinary” claims” to be treated somehow differently than “ordinary” claims is a nonsense. One simply cannot do that in science. All claims must be a priori treated equally according to the strict protocols of critical thinking, logic and the scientific method. Until the evidence is in, one simply cannot know what adjective might be applicable.

Originally Posted by ThunderChunky

I am going to require different levels of evidence to believe these two claims.

But that is just the point. You are saying here that you actually require a greater weight of evidence to convince you of … what precisely… that your a priori belief is incorrect? But that is only your particular belief system and it may be completely misguided (ie; not generalisable). That is why, in science (as in critical thinking and logic) such a priori belief systems are carefully guarded against. Generalisability not only applies post hoc but also a priori (so they cannot be held hostage to personal belief systems).

Originally Posted by ThunderChunky

The ordinary claim I may believe just on the look and smell alone.

Looks (and smells) can be deceiving.

Originally Posted by ThunderChunky

The extraordinary claim will require more evidence--extraordinary evidence.

More evidence according to your own particular belief system maybe (that is your subjective opinion), but how does more evidence equate to “extraordinary” evidence. “More” does not equal “extraordinary” by any accepted definition.

Originally Posted by ThunderChunky

I will need to observe evidence of the extraordinary nature of the claim. Just looking and smelling like coffee is not enough.

Now you are getting closer to it. But still you are second guessing the outcome.

Originally Posted by ThunderChunky

Ordinary claim: I went to taco bell for lunch.
Extraordinary claim: I ate lunch on the moon.

I will believe the first claim in most cases just on someones word because it's quite ordinary. The second claim will require more evidence.

No, the second claim merely requires evidence!

Moreover, you would not seek evidence for the first claim simply because it does not particularly matter to you one way or other. However, if your life or death hinged on the claim “I went to taco bell for lunch.” (such as a murder was committed at KFC during lunch, for which your are being blamed) then you would be required to supply evidence.

Moreover, to you, the claim that you were the murderer in KFC is an extraordinary claim – presumably because you know the evidence that you could not have been the murderer (a post hoc rationalisation in other words), but to the CSI police, who deal with these things all the time, the claim that you were the murderer is just an ordinary claim that they deal with generally all the time. To them the claim is entirely ordinary.

Your second claim (“I ate lunch on the moon.”) only seems extraordinary because we have already run over the circumstantial evidence against that claim in our minds (ie; that no space agency has recently sent any rockets to the moon and your name has never come up in relation to astronauts). Again, the claim only becomes subjectively “extraordinary” after we examine the evidence (in this case circumstantial – but it IS still powerful enough for us to reject your claim!).

If you (or anyone) maintained the claim, then we (anyone) would simply require evidence in support of that claim – and notably, the only evidence you could supply would be ordinary evidence. For example you were on a particular rocket that launched from a particular place and that landed on the moon at a time that allowed you to have lunch there). That is ordinary evidence. Nothing “extraordinary” about it at all.

So I am still waiting for Sagan’s “extraordinary evidence” to be defined and an example of it provided. Until then, it remains a nonsense phrase.

[Jeff Wagg]

It's just as extraordinary to claim you have had lunch on the moon as it is to be able to prove it with a photograph, some rock samples, and a signed letter from NASA.

You have to fight Occam's razor here. If there's a simple and common explanation for something, you have to overcome it with stronger or better evidence, thus making your explanation the simpler one.

[Rramjet]

Originally Posted by tsig

You're trying to get anecdotes in as evidence aren't you?

That is an extraordinary claim! Therefore I require you to provide extraordinary evidence in support of it. What’s that? You cannot? Oh dear…

[Resume]

Originally Posted by Rramjet

So I am still waiting for Sagan’s “extraordinary evidence” to be defined and an example of it provided. Until then, it remains a nonsense phrase.

You typed "evidence is evidence." Perhaps you might provide an example.

Anecdote doesn't get it.

[Alan]

A claim is called "extraordinary" based on how the evidence for it and the evidence against it compare.

Do you understand that, at least?

[Patricio Elicer]

Originally Posted by Rramjet

No, the second claim merely requires evidence!

Exactly!, and that evidence must be extraordinary. A piece of evidence of the like "a friend of mine told me he had lunch on the moon" is not enough, though it would be enough for the claim of "lunch at the KFC". Why?, because the extraordinary evidence of poeple having lunch at KFC already exists.

Quote:

So I am still waiting for Sagan’s “extraordinary evidence” to be defined and an example of it provided. Until then, it remains a nonsense phrase.

You've been told and explained over and over, comprehensibly. If you don't want to listen, that's another matter.

[Rramjet]

Originally Posted by Patricio Elicer

We cannot know that a claim is extraordinary, but we can make a judgement that it is.

We can judge a claim to be extraordinary when, if true, it would revolutionize our knowledge of the natural world and/or oblige us to modify the laws of physics that have been experimentaly corroborated over and over again for centuries.

So, please answer this: if I say that I can move physical objects solely with the power of my mind, is it ordinary or extraordinary claim?

Yes, but that judgement of yours is a post hoc rationalisation, made [i]after[i] consideration of the extant evidence.

No, I don’t see your claim as extraordinary at all. Many, many people have made such a claim throughout history. It seems an entirely ordinary claim to make in the context. That does not mean that I necessarily believe that claim. I would of course require you to provide evidence for that claim before I did.

But answer me this: What evidence could you supply (if your claim was true) that would constitute "extraordinary evidence"?

[Rramjet]

Originally Posted by Patricio Elicer

Exactly!, and that evidence must be extraordinary. A piece of evidence of the like "a friend of mine told me he had lunch on the moon" is not enough, though it would be enough for the claim of "lunch at the KFC". Why?, because the extraordinary evidence of poeple having lunch at KFC already exists.




You've been told and explained over and over, comprehensibly. If you don't want to listen, that's another matter.

You are (as it seems most people here are) missing a critical point in my argument. So far all you have been describing to me is ordinary evidence (eg: "people having lunch at KFC" is entirely ordinary). However, you all seem to be equating “more evidence” with “extraordinary evidence”. “Look” and “smell” is not enough evidence in particular circumstances because, while for day-to-day purposes it does not particularly matter if we get it wrong, on weighty issues, such as life or death, then more evidence than mere “look” or “smell” is needed – and more evidence is needed because we know look and smell can be deceiving. I can only reiterate” More does not equal “extraordinary”.

Cannot anyone give an example of “extraordinary evidence”?

[Resume]

Originally Posted by Rramjet

Cannot anyone give an example of “extraordinary evidence”?

Yes. The predictive qualities in evidence for the theory of evolution. Think transitional, think Tiktalik. Extraordinary indeed.

[Patricio Elicer]

Originally Posted by Rramjet

Yes, but that judgement of yours is a post hoc rationalisation, made [i]after[i] consideration of the extant evidence.

I don't understand this. As I said, it's a judgement based on the impact that such a claim, if true, would have on our knowledge of how the world works.

Quote:

No, I don’t see your claim as extraordinary at all. Many, many people have made such a claim throughout history. It seems an entirely ordinary claim to make in the context.

Looks like you didn't read what I wrote. A claim does not become ordinary because many people have made it, but because of the reasons I stated above.

Quote:

But answer me this: What evidence could you supply (if your claim was true) that would constitute "extraordinary evidence"?

I would do a demonstration of my powers in front of the most knowledgeable and skeptical scientists and magicians, in whatever controlled conditions they choose. I would allow any kind of measurements they choose to do. I would repeat my demonstration any number of times they request.

[paximperium]

Originally Posted by Rramjet

But answer me this: What evidence could you supply (if your claim was true) that would constitute "extraordinary evidence"?

Already answered it.
Conclusive irrefutable evidence or series of evidence that is superior to the evidence against the claim.

In other words, either move the object right now that will withstand scrutiny that it isn't a trick or fraud(which all prior knowledge says it will likely be) or give me more evidence than the evidence shows that you are not insane.

You see:
Moving an object with your hand is "ordinary" evidence. It could be a complete trick. Some magicians enjoy doing mundane tricks. Tricks that require complex skills but look like normal activity by laypeople but then no one will care.

Moving an object with your "mind" will require "extraordinary" evidence. This will require more controls to prevent things like fraud or trickery as the cause of this effect is unknown and that this is universally done via trickery.

[paximperium]

Originally Posted by Rramjet

Cannot anyone give an example of “extraordinary evidence”?

An actual anti-gravity flying saucer.

[Chris L]

Quote:

Many, many people have made such a claim throughout history.

Number of proven claims of such == 0. The claim is extraordinary because it violates what we currently know about how the universe works.

[SezMe]

Originally Posted by Patricio Elicer

We cannot know that a claim is extraordinary, but we can make a judgement that it is.

We can judge a claim to be extraordinary when, if true, it would revolutionize our knowledge of the natural world and/or oblige us to modify the laws of physics that have been experimentaly corroborated over and over again for centuries.

I think this is very well said and addresses the OP in a definitive way.

[Rramjet]

Originally Posted by Alan

A claim is called "extraordinary" based on how the evidence for it and the evidence against it compare.

Do you understand that, at least?

But it is only judged to be so after the evidence has been examined (a post hoc rationalisation in other words). That is why one cannot apply a general claim such as “extraordinary claims require extraordinary evidence” as an a priori general rule – because a priori we have no idea what might constitute and extraordinary claim (and that is even before we get to trying to understand what on earth might constitute "extraordinary evidence”).

Please tell me you understand that at least.

[SezMe]

Originally Posted by joobz

Here's an example of a pendantry gone wrong.

I make the extraordinary claim that this post is manna from heaven. I once made the same utterly embarrassing mistake and got called on it. That I now get to call a fellow poster on it gives me untold pleasure.

[pedant]pedantry[/pedant]

[paximperium]

Originally Posted by Rramjet

But it is only judged to be so after the evidence has been examined (a post hoc rationalisation in other words). That is why one cannot apply a general claim such as “extraordinary claims require extraordinary evidence” as an a priori general rule – because a priori we have no idea what might constitute and extraordinary claim (and that is even before we get to trying to understand what on earth might constitute "extraordinary evidence”).

Please tell me you understand that at least.

No. It's been answered:

Originally Posted by Patricio Elicer

We cannot know that a claim is extraordinary, but we can make a judgement that it is.

We can judge a claim to be extraordinary when, if true, it would revolutionize our knowledge of the natural world and/or oblige us to modify the laws of physics that have been experimentaly corroborated over and over again for centuries.

[Loss Leader]

Originally Posted by Rramjet

Cannot anyone give an example of “extraordinary evidence”?

Well, RJ, you're right ... sort of. When lay people talk about evidence, they're using common sense definitions in what is actually a highly specialized field. I studied for years to understand the rules of evidence and I apply those rules in practice every day to convince people of my way of thinking.

Throwing legal jargon around isn't gonna help anyone, though. So let me come at it another way.

If I want to say, "Bob drives a red car," I'll need evidence. So, I produce his neighbor, who sees a red car parked in Bob's driveway, his coworkers who see Bob get into a red car at the end of the day, and a traffic cop who saw a red car with a flat time on the side of the road and stopped to find Bob next to the car.

That seems like decent evidence that Bob drives a red car. However, there's a lot of evidence I could have included but didn't: whether Bob even exists; whether Bob ever learned to drive; whether Bob's finances allow him to afford a car; whether Bob knows how to change the oil on a car; and more.

All of that would help make it more likely that Bob drives a red car.

Why didn't I include witnesses to testify to those things? Because assuming that Bob exists, can drive, knows the rules of the road, manages to swing the price of gas, etc. - those are all easy assumptions. They are consistent with what we know about the vast majority of people like Bob.

Now, imagine that I wanted to prove that Bob was, although human, originally born of Tau Ceti 6. The problem there is that we have no knowledge whatsoever about what that type of person would or would not be like. So we can't make any assumptions.

In order to prove the matter, then, we'll need much, much more exhaustive evidence. What we know about life won't help us this time.

And all that evidence must be consistent with everything else we already know.

So, I wouldn't say that extraordinary claims require extraordinary evidence. I would say that claims which are not part of normal human experience require far less information be assumed, and thus demand that far more information be aduced.

[Patricio Elicer]

Originally Posted by Rramjet

Cannot anyone give an example of “extraordinary evidence”?

Here you go:

Claim: "Extraterrestrial intelligent beings exist"

Extraordinary evidence: A body of an extraterrestrial intelligent being that scientists can confirm as such.

[Chris L]

Quote:

But it is only judged to be so after the evidence has been examined (a post hoc rationalisation in other words).

Again, no. The evidence is what the person making the claim is going to provide. Take the lunch on the moon example. I, as an observer, can judge the claim as extraordinary before viewing and judging his/her evidence, if the claim does not conform to what is known about how the universe in general, and space flights to the moon in particular work.

The evidence provided for such a claim must therefore be more than the "here I picked up a rock on the moon for you" kind.

[Towlie]

I just ran across this thread, and it seems to tie in well with the news of Stephen Hawking's new book. According to the reports, Hawking says this:

Quote:

“Because there is a law such as gravity, the Universe can and will create itself from nothing. Spontaneous creation is the reason there is something rather than nothing, why the Universe exists, why we exist.”

Now there's an extraordinary claim if ever I've heard one. What sort of extraordinary evidence shall we require of it?

[Rramjet]

Originally Posted by paximperium

Already answered it.
Conclusive irrefutable evidence or series of evidence that is superior to the evidence against the claim.

But that is merely ordinary evidence. How does evidence that is “conclusive” or “irrefutable” or that is part of a ‘series” or somehow “superior” make it extraordinary?

Originally Posted by paximperium

You see:
Moving an object with your hand is "ordinary" evidence.

Agreed. So perhaps I can come at this from a different angle. Critically, what makes it “ordinary”?

[Chris L]

OK, back to the lunch on the moon thing. If the person telling me he had lunch on the moon once is Buzz Aldrin, his word is all the evidence he really needs to provide. If on the other hand, the person telling me this is some semi-literate guy who wrote a book about secret space programs and is claiming to have made the trip in a secret spaceship that uses anti-gravity devices, I'm going to need a whole lot of evidence about who he really is, who he has worked for, where he went to school, just for starters. In fact, unless he can land the thing in my yard to look at it, not much will convince me. That is extraordinary evidence.

[paximperium]

Originally Posted by Rramjet

But that is merely ordinary evidence. How does evidence that is “conclusive” or “irrefutable” or that is part of a ‘series” or somehow “superior” make it extraordinary?

Because it has to meet a burden that is much higher than any mundane claim since it has to overwhelmingly contradict all that is known.

Having one scientific study that confirmed Einsteinian Relativity is pretty mundane. It is likely just accepted without much scrutiny.
Having one scientific study that contradicts Einsteinian Relativity is extraordinary. It is not just accepted. It is placed under more scrutiny. It will be repeated multiple times before it is accepted.
Having one scientific study that conclusively allows man to float using superduper Gravitons would be pretty conclusive extraordinary evidence.

Quote:

Agreed. So perhaps I can come at this from a different angle. Critically, what makes it “ordinary”?

A claim that is consistent with what is known.

[Chris L]

Quote:

Critically, what makes it “ordinary”?

It's not that hard. It's an ordinary claim because it is well within the bounds of what is known to be possible.