Does an extraordinary claim require extraordinary evidence?

[harvey1]

Once in a while, you get this doozy of a phrase that many people just agree with because it sounds good. However, I disagree with this statement. In fact, I would say that the extraordinary nature of a claim is only loosely related to extraordinary evidence. That is, it's possible that the evidence supporting an extraordinary claim could be extraordinary, but most of the time, the evidence is not so extraordinary.

Rather, evidence usually accumulates until it forces a paradigm shift in understanding, and it is very often the straw that breaks the camel's back that all the "extraordinary" evidence is re-interpreted in light of the new paradigm. Once the new paradigm is accepted, the former neglected evidence is seen in this new light, and the old paradigm is then seen as being very unsatisfactory to say the least.

So, since people like catch phrases, how about "drastically different paradigms in thought require enough evidence that leads to a drastic re-interpretation of all the available evidence"? Does anyone disagree and still maintain that extraordinary claims need extraordinary evidence?

[The Persnickety Platypus]

Seems to me that the fashion in which the extraordinary claim is presented makes a big difference.

Persuasion often trumps evidence. Hitler is a prime example. Convincing an entire nation that their probems are the workings of a completely irrelevant minority is no easy task. He fed off his people's emotions and desire. A debater who can effectively harness the art of language rarely needs evidence to back his claims.

I could cite off any stream of meaningless rhetoric, strategically place some big words here and there, and probably convince even the most seasoned debater that my position is correct.

Emotions play a big part in perception, much moreso than we are willing to admit. This is one of the reasons I believe no evidence can be considered objective.

I agree with harvey on a fundamental level. Every claim needs evidence, but often evidence is not requested. People will see someone that seems substantially more intelligent than themselves present an argument, and naturally assume that they know what they are talking about. This is not always the case of course, which is why we should always seek validation of claims.

[McCulloch]

I agree with harvey on a fundamental level. Every claim needs evidence, but often evidence is not requested. People will see someone that seems substantially more intelligent than themselves present an argument, and naturally assume that they know what they are talking about. This is not always the case of course, which is why we should always seek validation of claims.

I agree with limits. In this post you have made at least five claims:

1. Every claim needs evidence
2. often evidence is not requested.
3. People will see someone that seems substantially more intelligent than themselves present an argument, and naturally assume that they know what they are talking about.
4. This is not always the case
5. which is why we should always seek validation of claims.

If you were to present validation of each of these claims, then in the process you would have made more claims, multiplying the number of claims requiring validation. Thus, we should not always seek validation of all claims. Practicality requires us to select which claims we will seek validation for. Thus some claims require little or no validation, some require an ordinary level of validation and some require an extraordinary level of validation.

[keltzkroz]

Why not just reword the damn thing and say 'claims need proof' (not just evidence)?

[harvey1]

You are mistaking the nature of extraordinary claims as contrasted with ordinary claims. Ordinary claims do not require extraordinary evidence.

Why do you feel compelled to get into a subjective game as what someone considers ordinary and extraordinary? Why not just say that any scientific claim must eliminate other reasonable possibilities to be a valid scientific claim? Why take this added step into subjectiveness that is not required? Look, I think I know what you want to say with this phrase. You want to say, I think, that some claims seem extraordinary and therefore we should be skeptical about them because these kind of claims are more likely to be false. However, the reason that they are more likely to be false is because there are many more mundane ways to explain an observation other than by making an extraordinary claim. However, if that is the case, then why add that extra step in the process of investigating the phenomena by first subjectively labelling it as "extraordinary"? Why not skip that step and just say that there are many reasonable explanations available for that phenomena, and therefore this is a situation that we have to eliminate all the contending hypotheses?

Let's say the claim is "There is a farmer named Bob." That's an very ordinary claim, and no evidence need be produced for we reasonable people to believe it is true.

Well, there is a good reason to doubt it if we have no evidence for Bob being a farmer. It is more likely, I grant you, that Bob can be shown to be a farmer since we can eliminate other reasonable possibilities rather quickly. For example, Bob has an address on his driver's license, and we can verify that this address is a farm address. We might have other people who testify that Bob is a farmer, etc.. We have eliminated any reasonable possibility that Bob is not a farmer. We don't take it on faith, we have simply come to this conclusion quickly because the evidence is accessible enough to elimiinate any other reasonable possibility.

No doubt there are several farmers named Bob within 100 miles of anywhere in the continental US.

Of course, but that doesn't tell you if our Bob is a farmer. You need to validate it, not just believe it. It might be false, and you have been needlessly misled.

Another ordnary claim might be "There is a farmer named Bod at this address..." This claim might require a little evidence to support it, if you were sufficiently interested. But since it is ordinary, the evidence it needs to support the claim is also very ordinary. A name in a phone book, for example.

Juliod, what you are trying to do in this process of looking at a name in a phone book? You are trying to eliminate any other reasonable possibility. This is what it means to validate something so that you can claim it to be true.

If you say "There is a farmer at this address named Bob who committed multiple murders" then you are moving into the realm of "extraordinary". Obviosuly in this case we would need to seek comprehensive evidence before accepting it. The sort of things the police would, in fact, seek.

Again, you validate that claim by eliminating the reasonable possibility that someone is lying, or is delusional, or is trying to get even with Bob, etc.. The evidence you seek is to corroborate that claim with evidence that would eliminate all those other possibilities.

Again, the standard is higher again if the claim is "Farmer Bob possesses a wide range of psychic and telekinetic powers."

I disagree. The standard is not higher. All that is "higher" is the difficulty needed to eliminate those other reasonable possibilities. The standard for all claims to knowledge are the same: eliminate other reasonable possibilities. Nothing less will do as a claim to knowledge.

[McCulloch]

You are mistaking the nature of extraordinary claims as contrasted with ordinary claims. Ordinary claims do not require extraordinary evidence.

Why do you feel compelled to get into a subjective game as what someone considers ordinary and extraordinary? Why not just say that any scientific claim must eliminate other reasonable possibilities to be a valid scientific claim? Why take this added step into subjectiveness that is not required? Look, I think I know what you want to say with this phrase. You want to say, I think, that some claims seem extraordinary and therefore we should be skeptical about them because these kind of claims are more likely to be false. However, the reason that they are more likely to be false is because there are many more mundane ways to explain an observation other than by making an extraordinary claim. However, if that is the case, then why add that extra step in the process of investigating the phenomena by first subjectively labelling it as "extraordinary"? Why not skip that step and just say that there are many reasonable explanations available for that phenomena, and therefore this is a situation that we have to eliminate all the contending hypotheses?

Someone correct me if I am wrong, but it looks to me as if Harvey and Juliod are saying essentially the same thing. Juliod adds subjectivity at the point where he identifies a claim as being ordinary or extraordinary. Harvey inserts subjectivity in identifying what are the reasonable possibilities. The end result of either of these two approaches seems to be the same; given the choice between a reasonable explanation for a particular phenomena and an extraordinary one, we should always favour the reasonable one.

[harvey1]

Someone correct me if I am wrong, but it looks to me as if Harvey and Juliod are saying essentially the same thing. Juliod adds subjectivity at the point where he identifies a claim as being ordinary or extraordinary. Harvey inserts subjectivity in identifying what are the reasonable possibilities. The end result of either of these two approaches seems to be the same; given the choice between a reasonable explanation for a particular phenomena and an extraordinary one, we should always favour the reasonable one.

There's a significant difference in these two positions. Juliod's position is an evidentialist position. I would state his position as:

Extraordinary Evidentialist position: pE is justified for some agent S at time t iff S's total evidence at t extraordinarily supports pE

My position is not committed to evidentialism. I'm only committed to a means of eliminating all other reasonable possibilities, but I don't specify that. Obviously, evidence is part of that, but I admit other factors such as the use of the scientific method for scientific claims. I don't think evidence is theory independent. I think most evidence is theory-laden, so I don't think it is sensible for evidence to be treated objectively (e.g., it is "extraordinary") when this is all subjective. My position would allow other means to decipher reasonable possibility as follows:

Eliminating Other Reasonable Possibilities position: all varieties of p are justified for some agent S at time t iff S's total experience of eliminating all reasonable possibilities at t supports p

As I said, this position is more generous and doesn't prejudice the mind with respect to what is extraordinary given one's particular ideology.

[The Persnickety Platypus]

If you were to present validation of each of these claims, then in the process you would have made more claims, multiplying the number of claims requiring validation. Thus, we should not always seek validation of all claims. Practicality requires us to select which claims we will seek validation for. Thus some claims require little or no validation, some require an ordinary level of validation and some require an extraordinary level of validation.

What I meant was more along the lines of 'don't take claims for granted; think for yourself'.

I didn't know my statement was going to be taken verbatim. But I accede, you are right. Many claims do not need verification. They are generally accepted, or can be observed in first person.

What should I say then? Claims that do not have an immediate, visible correspondence with that of our perception of reality require validation?

[juliod]

The problem we are having here (as I see it) is that people unaccustomed to rationalism seem to want some sort of "official" truth. Whereas in the real world (the only one we have access to) we can't get this sort of truth.

The real question is when do reasonable people believe something is true? This question inherently allows for the fact that this assessment may change.

Why do you feel compelled to get into a subjective game as what someone considers ordinary and extraordinary? Why not just say that any scientific claim must eliminate other reasonable possibilities to be a valid scientific claim?

This is a fundemental aspect of truth claims. There is a gradient of ordinariness just as there is a gradient of quality and/or quantity of evidence.

Your second question ignores whole classes of ordinary scientific claims that do not require extreme evidence. For example "The melting point of new compound X is 45 C". That does not decide between alternatives, nor does it need significant evidence to support it's truth to reasonable people.

(But if the claim were extraordinary, "the melting point is 50,000 C", then some serious evidence would be necessary before it would be believed.)

Why take this added step into subjectiveness that is not required?

BTW, I'm not sure it is subjective. I think a philosopher could propose a quantification of extraordinariness.

You want to say, I think, that some claims seem extraordinary and therefore we should be skeptical about them because these kind of claims are more likely to be false.

I think you are thinking that because you have been exposed to supernaturalism with it's massive number of already-falsified claims.

Consider instead the claim that minerals in meteorites may be fossils from Mars. Reasonable people make no pre-determination about the truth of that claim, merely recognixing it as extraordinary and in need of very significant evidence before it is embraced.

Why not skip that step and just say that there are many reasonable explanations available for that phenomena, and therefore this is a situation that we have to eliminate all the contending hypotheses?

One reason for not doing that is that we may need to wait an unknown period before getting sufficient evidence to form a firm conclusion. The other reasonable explanations may have no evidence to support them. We are left (as with the Mars fossils) with one theory that has some evidence to support it but which is not enough to allow us to form a firm conclusion. We note the theory, note the evidence, then stop worrying about it.

Well, there is a good reason to doubt it if we have no evidence for Bob being a farmer.

The first claim about farmer Bob was not about any specific person, but just as written: that there exists a farmer named Bob somewhere. Since we have a common name and a common profession, there is no need to look for additional evidence to conclude it is true.


Note: Gotto go. I'll continue later...

DanZ

[juliod]

Let's see, where was I...

Of course, but that doesn't tell you if our Bob is a farmer. You need to validate it, not just believe it. It might be false, and you have been needlessly misled.

When the claim is very ordinary (not to say, mundane) such a "There is a farmer named Bob" then we already possess sufficient evidence to draw a conclusion. There are many many claims like this since we all possess a fairly broad range of personal experiences.

Juliod, what you are trying to do in this process of looking at a name in a phone book? You are trying to eliminate any other reasonable possibility. This is what it means to validate something so that you can claim it to be true.

That's true. But a name in a phone book is "ordinary" evidence, and not of a particularly high standard. But if the claim is also ordinary it is sufficient for belief by reasonable people. For 99% of claims we encounter we will not go beyond this stage.

Again, you validate that claim by eliminating the reasonable possibility that someone is lying, or is delusional, or is trying to get even with Bob, etc.. The evidence you seek is to corroborate that claim with evidence that would eliminate all those other possibilities.

in this case I don't think your standard holds. For example, if we convict Bob of murder but he was merely present at the scene but chooses not to implicate the guilty, we have not eliminated other possabilities. We always have to live with those possabilities. Adn that's as far as we usually go in the jury process.

OTOH, if a historian wants to claim that Lee Harvey Oswald didn't do it, then they will need to produce extraordinary evidence beyond what the investigations have left to us.

The standard is not higher. All that is "higher" is the difficulty needed to eliminate those other reasonable possibilities. The standard for all claims to knowledge are the same: eliminate other reasonable possibilities. Nothing less will do as a claim to knowledge.

I don't think that is true. And I say it would be impossible to live that way. Can you really not distinguish a difference between these unsupported statements:

1) There is a farmer named Bob someone in the US.

2) There is a farmer named Bob who lives at .... and possesses a wide range of supernatural powers.

DanZ

[harvey1]

Why not skip that step and just say that there are many reasonable explanations available for that phenomena, and therefore this is a situation that we have to eliminate all the contending hypotheses?

One reason for not doing that is that we may need to wait an unknown period before getting sufficient evidence to form a firm conclusion. The other reasonable explanations may have no evidence to support them. We are left (as with the Mars fossils) with one theory that has some evidence to support it but which is not enough to allow us to form a firm conclusion. We note the theory, note the evidence, then stop worrying about it.

However, this leaves us with a good reason for not accepting that Mars necessarily had life hypothesis. It's not that the claim is so extraordinary, it's that it involves a new paradigm and we haven't eliminated the old paradigm yet. The old paradigm is that meteorites are easily contaminated by earth, life is a unique phenomena seen only on earth, etc.. Until we have sufficient cause to eliminate these other reasonable possibilities (i.e., we have to wait an unknown period before getting sufficient evidence to eliminate the current paradigms), we continue using a paradigm where the elimination of other reasonable possibilities allowed us to arrive at that paradigm. This has nothing to do with extraordinary claims per se, it has more to do with claims that wish to overthrow a current paradigm without providing sufficient reason to do so (i.e., by eliminating the reasonable possibilities proposed by the current paradigm).

At first glance, this might appear to be saying the same thing (as McCulloch said), but because the emphasis of my non-evidentialism is on elimination of other reasonable possibilities (and not on producing some "extraordinary" evidence), I have other means available to switch paradigms that you do not have. For example, it's possible that someone might show that there's a problem with the current paradigm because the process used to arrive at it was faulty. This might trigger a re-interpretation of the evidence that favored that paradigm, and suddenly the situation is reversed where the other reasonable possibility of the current paradigm has been eliminated. No new or extraordinary evidence was found (contrary to the requirement you set forth), however a re-interpretation occurred which changed our understanding of the currently available evidence.

Since we have a common name and a common profession, there is no need to look for additional evidence to conclude it is true.

Let's translate this into my non-evidentialism language: since we have a common name and a common profession, there are no reasonable possibilities that a farmer could necessary not be named Bob. It doesn't matter how I come to this knowledge that it is not reasonably possible. I might look at some hard evidence that samples name frequency, etc., but I might also come to it by utilizing commonsense. It's not the nature of the claim being ordinary or extraordinary that is important, it is the nature of what I consider reasonably possible.

if we convict Bob of murder but he was merely present at the scene but chooses not to implicate the guilty, we have not eliminated other possabilities. We always have to live with those possabilities. Adn that's as far as we usually go in the jury process.

If there were a trial for Bob, the jury's chief responsibility is to find whether there is reasonable doubt that Bob had committed the crime. It is not to see whether there is extraordinary evidence to convict him of this extraordinary claim. The problem with your approach is that convictions would plummet because jurists would be looking for extraordinary evidence when there is none. My approach does not have those kind of consequences since the jurists are charged with the responsibility of eliminating other possibilities by any method that the judge allows.

if a historian wants to claim that Lee Harvey Oswald didn't do it, then they will need to produce extraordinary evidence beyond what the investigations have left to us.

Perhaps they don't. All the evidence available eliminates other reasonable possibilities (such as the Secret Service did it, etc.). If, on the other hand, it could be shown that the Secret Service has a severly tarnished image going back into the 1950's, then the only reasonable possibility that Oswald acted alone has been dealt a blow. The "extraordinary evidence" that you seek has not really come forward since we know nothing new about Oswald. Rather, we just have new reasons to doubt what had before seemed unreasonable. Our former paradigm is no longer satisfactory to eliminate other possibilities.

And I say it would be impossible to live that way

Actually, I think this is how we do live, and it is your evidentialism which would be impossible. Most of the claims that happen in life are of the variety that they are unlikely (and therefore extraordinary) if seen as a teleological requirement. Let me give you an example. I am here typing this post to you, and if we go back a few decades and someone would ask, what are the chances that this guy here and that guy there (assuming you were born a few decades ago...) would be corresponding with each other on such and such a date about a philosophy of science issue, then it would be exceedingly unlikely for that to happen. It would be an extraordinary claim. According to your approach, this extraordinary claim could only be valid once there was extraordinary evidence to back it up, which would mean that once we started exchanging posts a while back this became the extraordinary evidence. However, this is an invalid way of accounting for the situation since our debating has never been extraordinary (except our responses, of course ). A more reasonable interpretation of those events is that a few decades ago it was unlikely that we would correspond on such and such an occasion because there are so many other possibilities. However, once those possibilities narrowed down by us arriving on the same website, it became a very reasonable possibility that we would discuss such issues. And, once we started this discussion a day or so ago, it eliminated any reasonable possibility that this discussion wouldn't occur.

Now, when you look at your way, and you look at my way, which is more reasonable? In my view, my way is more reasonable since your way places an extraordinary significance to each other miraculously finding our way on this planet of nearly 6 billion, and someone honing in on this topic for this exact date and time. That's ridiculous! It is much more parsimonious to explain this occurence as one of elimination of reasonable possibilities and that nothing extraordinary happened. No extraordinary claims could be made a few decades ago since, although unlikely for us to be discussing this exact topic as a 30-year prediction, it was certainly very likely that possibilities could be eliminated such that we would be having this discussion.

Can you really not distinguish a difference between these unsupported statements:

1) There is a farmer named Bob someone in the US.

2) There is a farmer named Bob who lives at .... and possesses a wide range of supernatural powers.

As I responded to (1) above, it is an unreasonable possibility for a farmer to not necessarily be named Bob. Your (2) is also a unreasonable possibility since self-avowed supernatural powers have always had other more parsimonious explanations, and therefore our current paradigm requires that we think that there are other reasonable possibilities that our paradigm favors. Let me add one of my own:

(3) There is a farmer named Bob who today happened to clean his garage by using an air compressor... this an extraordinary claim because 200 years ago there were no air compressors and who would have thought that farmer Bob would be doing that 200 years ago!


Extraordinary claims require extraordinary evidence? Nah. Claims with many reasonable possibilities require elimination of those other possibilities.