Extraordinary Claims require Extraordinary Evidence - A Crackpot Assertion

David Hume, in his An Enquiry Concerning Human Understanding, had this to say, back in 1748:

"When anyone tells me, that he saw a dead man restored to life, I immediately consider with myself, whether it be more probable, that this person should either deceive or be deceived, or that the fact, which he relates, should really have happened.... If the falsehood of his testimony would be more miraculous, than the event which he relates; then, and not till then, can he pretend to command my belief or opinion."
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Of course, there's much more than this in the text, about evidence and proof and miracles and when it is and isn't reasonable to believe something.

The basic ideas are simple, though. They include notions such as: the degree to which one should believe one claim over another ought to be proportional to the degree to which the evidence for one claim outweighs the evidence for the other. Or, put more simply: one's belief in a claim should be proportional to the evidence in support of it.

Hume defines a miracle as a "transgression of a law of nature by a particular volition of the Deity, or by the interposition of some invisible agent." He contrasts miracles with "laws of nature", which are established by "a firm and unalterable experience"; they rest upon the exceptionless testimony of countless people in different places and times. Hume is careful to distinguish the miraculous from the merely wondrous or unusual.

 

Ivan:

And yet, people mostly tend to agree about what is ordinary and what isn't, most of the time. So, it's not a useless term.

This is where weighing up competing theories becomes important. We don't just consider claims in isolation from everything else that is known. We compare competing claims.

Thus, in the example of a UFO sighting, one claim might be that the UFO was an alien spaceship, while a competing claim might be the the UFO was a mistaken sighting of the planet Venus. Which claim should we believe?

Hume says our belief in either of these claims should be proportional to the evidence for each, and the degree to which we ought to accept one claim over the other ought to be proportional to the degree by which the evidence for one outweighs the evidence for the other.

So, in this example, we need to look at all the evidence put forward for the Venus hypothesis, and compare it to all the evidence put forward for the alien spaceship hypothesis. Either claim might win out, conceivably; it depends on the strength of the evidence. (Any disconfirming evidence counts against a hypothesis, of course.)

But, at the same time, we should consider whether what is being claimed is akin to a miracle. And then, we ought to consider whether it is more miraculous for eyewitnesses to the UFO to be mistaken about the whole alien spaceship conclusion than for it to be true.

There have been countless confirmed sightings of the planet Venus, and not a single confirmed sighting of an alien spaceship, so far. So, in most cases, the sensible working assumption will be that it wouldn't be particularly miraculous for an eyewitness to a UFO sighting to make a mistaken identification, whereas it would be surprising in the extreme if it turns out that this time the UFO actually was an alien spaceship - the first one ever positively identified by human beings.

So, the problem, in such cases, is that there ought to be quite a strong presumption that the UFO was probably not an alien spaceship, but a mistaken attribution. That presumption is not a conclusion, of course. It's just one constant competing hypothesis whose weight of evidence needs to be compared against the competing hypothesis of the (miraculous - or at the very least unexpected) alien spaceship.

TBC...

 

(continued...)

You read the book, right? If I recall correctly, Sagan was pretty clear about evidence not equalling proof, both there and elsewhere.

All this is true, but largely irrelevant to the point you're trying to make. Nobody has demanded proof.

Denialist are called such because they ignore evidence they don't like. They are not in the business of weighing up the evidence for claim A (human activity is responsible for the current global heating trend) against claim B (the current global heating trend isn't real) against claim C (human activity does nothing to contribute to global heating). If the denialists did that in an unbiased way - like the real climate scientists do - they would quickly find that the weight of evidence is strongly in favour of claim A.
Pretending to care about evidence while denying its very existence is what makes somebody a Denialist.

It's easy to claim that the standard is set too high. Maybe you really think it is. But if so, perhaps you should calibrate the amount or quality of evidence that you, personally, require to believe in alien spaceships vs the amount or quality of evidence you require to believe in, say, Cold Fusion, or God, or the existence of Ottawa. If it turns out that you're going easy on the UFOs because you think it would be really cool if aliens were here, then maybe your standard of evidence needs a recalibration. The same goes if you're ignoring all of the UFO cases that turned out definitely not to be alien spacecraft.

The claims "ball lightning exists" and "alien spaceships are visiting Earth" are not competing claims. So, while it is conceivable that scientists have ballsed it up when it comes to ball lightning (see what I did there?), it doesn't mean they're wrong about the UFOs.

Anybody who says that nothing can change their mind about a belief they hold has a belief that isn't based on evidence. That's a very important thing to realise about people.

A lot of people believe a lot of things for reasons that have very little, if anything, to do with evidence. As a scientist, I'm sure you want to avoid making the same mistake when it comes to UFOs. Certainly, Carl Sagan wanted that.

Not necessarily. For instance, in the 1850s, extraordinary claims would have included "Invisible rays exist that can allow us to see the bones in people's bodies without breaking the skin" and "The continents move around on the surface of the Earth over long periods of time, radically reshaping the surface constantly, but slowly". But neither of these ideas was outside the bounds of imagination. In fact, you could argue that something like an x-ray machine was an "expected" future technology.

The existence of alien life has long been "expected". Many scientists expect it and give cogent argument as to why it is a reasonable thing to expect. On the other hand, the same scientists also tend to give cogent reasons for why aliens visiting Earth in spaceships should not be "expected", despite it being a theoretical possibility. But in the end, the evidence will decide the matter, one way or another, not the expectation.

If it was common, you'd think we'd have some good evidence for it by now, would you not? Or are you going to make "extraordinary" excuses?

What are you talking about? Our entertainment media is chock-a-block full of this possibility. We're bathed in a dominant culture of alien spaceship expectation.

Check your history. The extraordinariness of that idea wasn't the reason for Galileo's persecution. Not at all.

The fact that he is making this argument is hardly extraordinary, as I'm sure you'll agree. I'd even say it would be expected, from him.

It just means "out of the ordinary". It's not a magic word. It's not a technical, science word. And Carl Sagan was not writing for a technical, science, audience there, either.

There's no way to completely eliminate subjective interpretations. They are inevitable. But that's beside the point.

 

Ivan Seeking:

It seems that I told you something you didn't want to hear, and then you sort of switched off and didn't bother reading or considering the remaining content in my posts to you.

If you'd read through to the end, rather than trying to work out how to lash back at me, you would have noticed where I wrote this, for instance:

It just means "out of the ordinary". It's not a magic word. It's not a technical, science word. And Carl Sagan was not writing for a technical, science, audience there, either.​

This was you in the opening post, was it not?

What it really means is that if a person doesn't like a claim, they can set an arbitrarily high standard for acceptable evidence.
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Your complaint, as I understood it, was precisely this: that skeptics set an arbitrarily high standard of evidence for your UFOs.

What did I get wrong?

I addressed the subject as I understood it from your post. Maybe you could have communicated more effectively?

Bear in mind that, even though obviously you're a super expert who already knows all this stuff, you're not the only person who might read this thread.

I'm glad we are in agreement on that. Of course, that 5% figure is more or less just a figure you made up. Who says it isn't 1%?

Clearly, you haven't read much from me on the subject. Maybe you're wasting my time.

If you honestly don't have the first clue about how much I know about this subject, why would you post that, in your opinion, I don't know the first thing? The only reason I can see is that something about my reply to your thread made you angry and your first instinct was to lash out, rather than to discuss what upset you like an adult.

That was a quick flip-flop back to your original claim, again. And this, just after you said in the same post that this wasn't what you wanted to talk about.

Which is it, Ivan Seeking? Make up your mind.

Science and beliefs have nothing to do with each other? Well, that's an interesting claim. Perhaps you and I can have a separate discussion about that particular claim. This thread is probably not the place - unless you think it is, of course. It only took you a few sentences to start changing the subject. Fancy that.

Take it up with Hume. Oh, of course it's too late for that.

Anyway, if you weren't so busy looking for reasons to take exception and to get angry, perhaps we could have a more useful discussion. Are you willing to give it a try, or would you rather keep pretending that talking to me is beneath you?

You didn't ask me. Besides, you wouldn't want me to change the topic, would you?

I already accepted that "extraordinary" is not a technical scientific term. That does not, however, mean that it has no place in science. It just means "out of the ordinary" - you know, its usual everyday meaning. Like I explained. If you'd read to the end you would have seen that and you wouldn't have needed to repeat yourself.

Well done. QED. You win.

Should we close the thread now, or is there something else you'd like to talk about on this topic?

Let me know.

 

CC:

Most of what you wrote is, as usual, reasonable. I take issue to some extent with the last couple of quotes you used, however.

Medawar makes a valid point: that many scientists are not trained in the philosophy of science. Many do not think about how it is that they do what they do, in explicit terms. That, I think, goes some way towards explaining this:

What is happening with the shifty eyes is that this particular scientist probably appreciates that there are people out there whose job it is to look at people like him and explain what he is doing and how he is doing it, while also appreciating that he himself hasn't spent much time looking at the findings of any of those people, because he himself has been busy trying to find out more about natural world, instead.

The shifty-eyed look is the look you tend to get when you ask any expert a question that she recognises is out of her field of expertise. She wants to be helpful, seeing as you have gone to all the trouble to ask. But at the same time she knows that her best answer might not be very helpful. She might think that you're asking the wrong kind of expert.

This is not the part I take issue with, though.

I am inclined to disagree with Medawar's premise that scientists receive no tuition in scientific method. The problem is particularly obvious if we accept Bridgman's definition that "scientific method is what working scientists do". Scientist have all received tuition that has led them to do what they do in the ways that they do it.

So, although a scientist might be oblivious to the formal language around the "scientific method" that is used by philosophers of science, that does not necessarily imply that they have no implicit understanding of the method(s).

A separate issue is that one can be proficient in a skill without necessarily being able to explain to somebody else what it is, exactly, that enables the proficiency. At least, not beyond generalities like "practice practice practice".

Medawar's mistake, I think, is to assume that unless a person is formally trained in the language of the philosophy of science, one cannot be said to have "learned the scientific method". I'd say that, on the contrary, for most scientists, the relevant learning happens by osmosis, with modelling by teachers being the most obvious source of the relevant knowledge about method(s).

 

The main problem with Ivan Seeking's objection to ECREE is that he wants to pretend that it is a purely subjective standard. I'm not sure exactly how things land for Yazata on the matter.

I myself am more inclined to borrow from the legal profession and suggest that the sentiment behind ECREE is similar to what the law refers to as a "reasonable person" test.

When it comes to evaluating evidence for a claim, it should not be so much a matter of trying to work out what would satisfy any particular individual that the claim is true, because clearly that will vary from one individual to the next. Rather, one should take a step back and think about what sort and what degree of evidence ought to satisfy a hypothetical "reasonable person" of the truth of the claim.

The "reasonable person" is assumed to be somebody who doesn't have a special interest in the subject matter, or any particular bias towards one conclusion or another, before considering the evidence that is alleged to support the claim. The "reasonable person" is to be, as far as is possible, as "disinterested observer" of the claim and the evidence put forward to support it. Of course, this is an idealisation. There is no such thing as the perfect "reasonable person" or an "average person" or a "completely unbiased observer". But the abstraction in itself is a useful distancing mechanism. One removes one's own biases and wishful thinking out the outcome of the investigation and tries to imagine how things would appear to the hypothetical unbiased, "neutral" observer.

So, when it comes to that 5% of difficult-to-solve UFO cases, you might ask yourself: what should the reasonable person require, before he accepts the claim that "this particular UFO was an alien spaceship visiting Earth"? The reasonable person is aware that there exists no public confirmation of the existence of any other alien spaceship. If this one turns out to be the aliens, as claimed, it will be the first one publically confirmed as such. The reasonable person here doesn't have top secret military clearance. Assume that our reasonable person in this case is a well-educated member of the public with no special expertise in science, although from his general reading he is probably aware that science has not endorsed the existence of alien visitors to Earth so far.

Along with the evidence for the alien spaceship hypothesis, our reasonable person will, of course, be presented with facts that tend to go against that hypothesis, and asked to balance the evidence for and against before making a decision about what to believe (provisionally). So, for instance, our reasonable person will be made aware that every solved UFO claim has turned out not to be an alien spaceship, so far. Our reasonable person will also be made aware of the problems with anecdotal evidence, with human perception and memory, and so forth. And, of course, our reasonable person will be informed about the specific evidence in the particular case at hand: the radar records, the eyewitness accounts, the fuzzy photographs, the shaky video footage, and so on.

On the face of it, the claim that this particular UFO, this time, is finally the Real Deal, after decades of the non-appearance and/or misidentification of alien spaceships, is extraordinary (meaning "out of the ordinary"). Because the ordinary, in this case, is that alien spaceships are never positively identified as such. Therefore, it is important that when our reasonable person makes his judgment as to whether this one is the Real Deal or not, he doesn't blunder into error by rushing to accept poor or faulty evidence as sufficient to make the case. The bar should rightly be set high, because this first ever identification of an alien craft will be of momentous importance to humanity as a whole. Thus, the extraordinary claim should demand extraordinary evidence. So low-quality evidence, dubious evidence, untrustworthy evidence, shouldn't cut the mustard.

The bottom line here is that the question of what is or isn't an extraordinary claim is not a completely subjective one, like Ivan would have you believe. My claiming to have eaten corn flakes for breakfast is not an extraordinary claim. My claiming to have found an alien lifeform eating my cornflakes for breakfast is an extraordinary claim. Any reasonable person should be able to agree on that. And it quite sensibly follows that any reasonable person ought to demand a higher standard of proof for the latter claim than the former, in order to accept it as true and verified to an acceptable standard of proof.

 

With my previous post in mind...

I would put in on the level of a useful rule of thumb, similar to Ockham's razor.

None of us choose our beliefs. We become convinced of things. Subjectively, I agree that there is some room for variation among individuals as to which claims they personally regard as extraordinary. Also, as a matter of fact, there is a very wide spectrum in what different individuals are willing to accept as sufficient reason to believe a claim.

What Sagan was after with ECREE, I think, was a somewhat more objective standard.

No objective justification will ever satisfy all cognizers. Some people become convinced about a lot of things for reasons that have very little - if anything - to do with objective justifications. And once somebody is convinced of something, they can sometimes become inflexible about changing their minds in the light of new evidence - especially when their belief doesn't rely on objective evidence in the first place.

This is why I advocate a more objective standard. See my previous post. I'm confident Sagan had a similar view.

Science itself tends to be about valuing objective measures above subjective ones.

Try on the "reasonable person" test I referred to, above, for size. It doesn't appeal to lofty ideas of the totality of "humanity's experience collectively", but rather to the everyman's experience. It's more practical, I think, since nobody has access to the entirety of humanity's collective experience.

It's used in courts of law all the time. For instance, rather than looking at the actual mindset of an individual criminal defendant (something impossible to definitely access), courts tend to consider what a reasonable person in the criminal's general position should have considered, thought, known, etc. This is not always true. It varies from crime to crime, for instance. In some cases, specific evidence of the individual's actual intent is required for a crime, while in other cases the fact that a criminal "ought to have known" the likely outcomes of his actions is sufficient to sustain a conviction.

That's very similar to the "reasonable person" test. Your "collective community" is represented by an "average", moderately well-informed member of that community: the "reasonable person" in that community.

The justification is simple and common-sense: it is reasonable to demand extraordinary evidence for extraordinary claims. Not to mention prudent, because it's less prone to error. It's better to be conservative than reckless when it comes to deciding what you ought to believe.

When dealing with human subjects, it is impossible to ever escape entirely from subjectivity.

I don't think anybody has ever suggested it is either of those. Although, it does make logical sense, for a variety of reasons.