On the nature of evidence

[Stupid]

Trust, Faith, Knowledge

If someone recommends a qualified car mechanic to me...

I trust their opinion that the mechanic is qualified.
When the mechanic begins work on my car, I have faith it will get fixed properly.
It's only when It;s finished and I drive away, do I have the knowledge that it was fixed.

=S=

 

[athon]

Right - now that I have five minutes, I'll see if I can think clearly on these points.

For me, that's the easy part. The more serious considerations are "evidence for what?" and "of what quality is the evidence for that conclusion?".

The first question is, I think, what lies behind my line of thinking. 'What objective events caused this observation?' is the question we ask when we observe something in science. Of course, we can never know with absolute knowledge what created that observation - we can only use other observations to arrive at a safe conclusion.

I'm wondering if some people see the label of 'evidence' only relative to the objective event that produced that observation, while I'm seeing it as relative to all possible events that produce the observation. My problem with the former is that it is not practical, let alone possible that we can know with absolute certainty that an observation is therefore 'evidence'.

The difference, ultimately, is this - We might agree that observing X is evidence supporting model Y. Another observation, Z, is seen which goes against model Y being true. The observation of Z is stronger evidence.

The former label suggests that X is no longer evidence, as model Y is no longer useful. I tend to think X retains the label of 'evidence', even though it is weak and Y is no longer useful.

Is this clear, or do I need to think more on my phrasing?

A matter of personal taste, perhaps. "Skepticism" to me is the epistemological position that claims or assertions of knowledge must be testable and supported by hard evidence, and that knowledge is conditional, not absolute, and therefore subject to evolution and refinement based upon the amount and kind of evidence available.

"Psuedoskeptics" do exist, but I find that term so vastly overused by the woo-woo crowd that in many contexts it is all but meaningless.

The philosophy of skepticism is simple enough to define. However, defining a 'skeptic' is not. To what extent does a person have to apply that epistemology to their decision making to be called a skeptic, for instance? Life doesn't present simple categories of knowledge against which skepticism can easily be applied.

I know I have such an epistemology, however I also know I encounter a lot of decisions where I don't think skeptically, either intentionally or through habits of social thinking.

Because the first is a simple acknowledgement of anomalous data -- or evidence, if you will -- whereas the other represents an interpretation of that data. Once one begins interpreting data one is no longer a neutral observer. At some point, of course, interpretation has to occur, but if it is brought in prematurely it can bias the collection of additional data -- e.g., instead of simply collecting additional data and examining it to see what sort of patterns may emerge, one begins seaching specifically for data supporting the observation of fairies. When data is selected to fit a pre-supposed pattern, other explanatory patterns may be easily overlooked.

Good point.

Oh, certainly. In your first example, if something were empirically observed from a particle collision that wasn't predicted by the mathematical model for that collision -- that is, if it were observed many times -- then the mathematical model would be called into question. In that sort of situation the mathematical model is the hypothesis, or at least a part of it. If observation consistently fails to support the hypothesis, then the hypothesis is either refined or scrapped, as need be.

If that's what you've been saying, I have no disagreement there.

Ok, cool. We're on the right track then.

Now, on that first observation of data suggesting the possibility of a new particle, there would be a number of considerations. Observing the data representing the particle would be evidence for all manner of hypotheses - it is evidence of a mistake, evidence of a flaw in the method, evidence of a new particle etc. If the experiment is done again and the data is not repeated, then that in itself is evidence in favour of the 'mistake' model explaining the observation, and the previous maths is upheld. Yet I contend that that observation of anomalous data is still evidence of a new particle, even if it is weak and (on its own) insufficient to lend credibility to the 'new particle' model.

I initially had a different impression of what you were trying to convey, which seemed to be along the lines of just proposing an "explanation" out of whole cloth, and then going out to see if it was supported by evidence.

Well at some stage speculation has to arise, which I guess in some ways has to emerge from little more than the imagination. The vast majority of speculations die at first breath, which is good. I don't think we disagree at all there. But whether the observation that inspired the speculation could be called 'evidence' at all is what I'm contending.

If you had no pre-existing evidence at all for a model why would you have the model at all?

The observation has to come first, I agree. I can't possibly imagine how one could seriously speculate anything without an observation to speculate on.

The truth is that both demons and the flat Earth were invented to explain other observations, and the two just happened to get slapped together at some point.

Interesting point. I'd be more inclined to think that a speculation arises from a single observation initially, which can immediately on further thinking collect more collaborating observations, or 'evidence'. However in itself this is pure speculation - I wonder if there are any psychology papers on the matter.

Athon

 

[Skeptic Ginger]

I'll have to read the rest of the thread later, so my apologies for butting in uninformed as to the conversation, but there is a critical point to be made if it hasn't been already.

There is a distinction to be made between what is evidence and what does the evidence support. Those are two different things. If you are just asking if visions of fairies are evidence of fairies, we have sufficient evidence now to say they are not.

If this was the first time someone had such a vision and we had not yet collected enough evidence to conclude if the vision was of real fairies or just evidence of a particular neuronal activity in an individual's brain, the report of the vision would remain the same. It is still evidence, but it is not evidence of fairies. We learn later that it is not evidence of fairies. So what is it evidence of until sufficient evidence is collected to confirm the conclusion?

It is only tentative evidence of fairies. It never becomes actual evidence of fairies because it isn't evidence of fairies. The evidence cannot become something it isn't, just because we don't know at first what the reported vision actually is evidence of.

A false conclusion about what evidence means, or what evidence is evidence of, does not change the evidence. (Excluding quantum mechanics for the sake of the discussion.)

The evidence is the thing we observe, or measure, or experience, or find out about through someone else. How we perceive it is simply a step toward drawing a conclusion about it. The thing we perceive remains unchanged. The act of observing it doesn't change the evidence. Drawing a false conclusion about it doesn't change the evidence.

The natural world exists. How we perceive the natural world, how we observe the things in the natural world, are all subject to errors in perception and errors of conclusions. The evidence is the same and it is there for us to re-examine as we collect additional evidence. We can re-examine the evidence and improve our observations or revise our conclusions. None of that changes the evidence.

We know that drawing a false conclusion doesn't change the evidence. So the evidence that was not evidence of fairies that we can now conclude because of the totality of the evidence, never was evidence of fairies regardless of what false conclusions anyone had previously drawn. If the visions are not evidence of fairies now, they were not evidence of fairies then either.

I think where people get confused here is in how they are constructing sentences. But sentences can be properly constructed yet leave information unspoken. If one says they are examining anecdotal evidence of fairies, it sounds like one is saying the anecdotes are evidence of fairies. If you were to write that sentence to include all the information you were leaving out, one would say, one was examining anecdotes which people report believing they saw fairies. We shorten the sentence for convenience but in doing so, one must be careful to recognize you are really examining a report of a vision, you are not really examining evidence of fairies.

You can easily demonstrate that by asking yourself if the visions are indeed evidence of fairies. I think if you reconsider what the evidence is actually evidence of, you can see the sentence is shortened for convenience, but a vision of fairies is not evidence of actual fairies. It is evidence of a vision.

 

[Ivor the Engineer]

<snip>

If one says they are examining anecdotal evidence of fairies, it sounds like one is saying the anecdotes are evidence of fairies. If you were to write that sentence to include all the information you were leaving out, one would say, one was examining anecdotes which people report believing they saw fairies.

<snip>

I think most (sane) people implicitly parse the first sentence as:

anecdotal evidence of fairies.

Rather than:

anecdotal evidence of fairies.

I.e. the word anecdotal is used to express a measure of the quality or reliability of the 'evidence'.

Someone claiming they have seen a fairy is evidence of fairies, but it is also evidence for other (more likely) hypotheses which do not require the existence of fairies.

I think you'll have to be careful using the "it's evidence of a vision not fairies" line of reasoning, since it would be just as valid to say your perception of the anecdote is not evidence of the anecdote, just that you imagined you heard or read something you believe to be an anecdote about fairies. It doesn't really get you anywhere.

Like I've said before, we're all Bayesians at heart.

 

[sphenisc]

Are there real world situations like the Monty Hall Problem, where counter-evidence to one proposition doesn't necessarily increase the chance of another 'preferred' proposition being true?

 

[69dodge]

Just a general comment here. Not sure where it fits, exactly.

It's impossible even to decide whether a certain observation is evidence in favor of a given hypothesis or, on the other hand, is evidence against it, let alone to determine exactly how strong the evidence is, without considering other, competing, hypotheses that might explain the same observation.

A toy example: Before you are two urns. (These are the two hypotheses being considered.) Urn A contains 20 white balls and 80 black balls. I'll get to urn B in a moment. You don't know which is which; they are not labeled. With your eyes closed, you stick your hand into one and pull out a ball. You open your eyes and see that it's white. (This is the observation.) Does the white ball constitute evidence in favor of the hypothesis that you stuck your hand into urn A? Evidence against that hypothesis?

It depends.

If B contains 30 white balls and 70 black ones, the observed white ball probably came from B. If B contains 10 white balls and 90 black ones, the observed white ball probably came from A.

 

[Skeptic Ginger]

One should be careful here. It seems some people are confusing the validity or reliability of the evidence with the evidence itself.

Here's what I posted in the other thread to try to clarify these issues.

The Evidence: the thing, it's properties, whatever about the thing that one is using to determine something from.

The Observation: the observation, measurement, or whatever means one has to obtain the information from the evidence.

Communicating: communicating the observation, measurement, etc., which is actually separate from the observation itself.

The Conclusion: the thing one determines from the evidence, including concluding you cannot draw a conclusion from the evidence, or you can only say the evidence suggests something, etc.

These really are distinct entities...

You can see the confusion it causes in these discussions when people blur these things together. If one just recognized the parts here, we wouldn't be having such discrepant opinions. We'd likely find with a few exceptions that we mostly agreed with the underlying principles.

The following examples might help to distinguish these separate issues.

An anecdote in the medical history actually includes information the health care provider gleans directly. A person answering, "yes", to every symptom you ask about gives one a clue for example, and the provider then uses the patient's anecdotes as the actual direct evidence of something.

A patient answering a questionnaire in a medical research project is acting as a proxy observer and is reporting on evidence they observed. We may take into account such things as the reliability of patient's memory, observation skills, and so on. But the person answering the questions is, in essence, a proxy observer.

A patient rating pain on a scale is giving direct anecdotal evidence that they are really the only one who can tell you (though there are also objective observations that can be collected as well). In that case we need to use anecdotal evidence in research.

In the case of the patient's medical history, it is a combination of proxy observer and the medical provider's direct observation of the anecdotal account.

The conclusions drawn from the anecdotal evidence described above is a separate matter. In medical research we use systematically collected anecdotal evidence and compare it to controls to draw valid conclusions from such evidence.

So the anecdote can be direct evidence (containing information directly observed by the health care provider), it can be direct evidence communicated to someone (pain rating), or it can be evidence observed by a proxy observer and reported to the researchers by way of a survey or questionnaire.

You can see where this gets confusing if we don't distinguish between the evidence, the observation, communicating the observation, and the conclusion.

You cannot conclude a mirage, hallucination, or one's incorrect conclusion about what is observed is evidence of fairies and then say therefore, there is evidence of fairies, it just isn't convincing. Because there is not evidence of fairies. There is evidence people mistakenly assess evidence, but there is not evidence of fairies. It might be tempting to see the semantics here and think, there is evidence, it just isn't convincing. But that is really misleading and comes from the apparent semantics of how we are constructing our sentences.

 

[Skeptic Ginger]

I think most (sane) people implicitly parse the first sentence as:

anecdotal evidence of fairies.

Rather than:

anecdotal evidence of fairies.

I.e. the word anecdotal is used to express a measure of the quality or reliability of the 'evidence'.

Someone claiming they have seen a fairy is evidence of fairies, but it is also evidence for other (more likely) hypotheses which do not require the existence of fairies.

Your first statement seems to contradict your second.

But no matter, look at the problem another way. Is there evidence for fairies? Of course not. Yet by including all those possible conclusions for the person's anecdote in which they concluded what they saw was fairies, you have implied there is evidence, however weak and/or unconvincing, for fairies. But we know for all practical purposes, there isn't any evidence for fairies.

You don't have to use my, "evidence of a vision". I wasn't trying to argue semantics, I was pointing out a principle about what evidence is and is not. I can easily word it another way to make you happy. There is evidence that an individual concludes is evidence of fairies, but it is not really evidence of fairies. You can word it anyway that you think meets perfection as you see it. Except, you cannot say that because someone draws a conclusion about some evidence, that the conclusion becomes the evidence. And that is in essence what you are doing if you say that the person who believes what they experienced was X, means the experience was actually evidence for X.

Now to head off the obvious follow up problem here, at what point is something evidence for something, if we are all just collective individuals drawing conclusions? That is one of the things managed by the uncertainty language and principle of science. The evidence remains the same (excluding quantum observations). So all the wrong conclusions in the world don't make the evidence into something it is not.

For the vast majority of what we encounter, the evidence is either overwhelming, convincing, suggestive of, inconclusive and/or plausible, etc. So when I say there is evidence of X, I am still saying I see evidence and am drawing a conclusion about that evidence by saying it is evidence of X. If it is overwhelmingly likely the conclusion is correct, then we don't question the way the sentence is constructed. We agree that the evidence is evidence of X. This is true even if the evidence is only suggestive, or plausible but inconclusive.

But if you do not recognize that the way we construct the statement doesn't actually make something evidence for something it is not evidence of, you don't leave yourself that one particular thing you need to occasionally communicate, that there is no evidence for fairies (and a few other things).

Most of the time, what you are saying is the most practical way of looking at the statement construction of a bad conclusion, "but it is also evidence for other (more likely) hypotheses which do not require the existence of fairies". In that respect I totally concur. But regardless of how you word this, you are still making a statement that includes a conclusion about the evidence for fairies. If you remove that conclusion, and you just consider the evidence, is it really evidence of fairies? No. Did the evidence change because of what you concluded about it? No. Did it change because of what the individual who believed it was evidence of fairies concluded about it? No. Do we include a conclusion when we refer to evidence? Often, but not always. Is the conclusion actually part of the evidence? No. And that is where the problem here is originating. We are used to including the conclusion in the statement about evidence, but it is not mandatory to do so. The conclusion about the evidence is really something separate from the evidence.

You could put, "We think", "we believe", "we conclude" or something to that effect in the beginning of every statement that [Y] is evidence of [X]. That might solve the problem if people recognized that such an unspoken qualifier was actually in every statement that said [Y] is evidence of [X]. Then you have segregated the evidence from the conclusion and can see that it is separate.

 

[athon]

One should be careful here. It seems some people are confusing the validity or reliability of the evidence with the evidence itself.

This is essentially my point. And this thread more or less validates the view that 'evidence' is not a clear term which is faithfully understood in the same way by everybody.

I don't think there is much of an argument on the fact that some observations are stronger forms of evidence supporting of a model than others. It is more about whether something can be called evidence at all, and the nature of the term evidence in relation to a poorly or weakly supported model.

I know a lot of respondants have been people who haven't read the thread (and therefore followed its progress), but I still think many of the responses reflect the confusion people have in the matter. While I'm not venturing to suggest my view is the 'right' one, I am anxious to point out that this confusion is important when considering how we communicate skepticism.

Athon

 

[Skeptic Ginger]

... I still think many of the responses reflect the confusion people have in the matter. While I'm not venturing to suggest my view is the 'right' one, I am anxious to point out that this confusion is important when considering how we communicate skepticism.

Athon

I'll venture to suggest my view is the right one , but I confess I was at first astounded by the confusion and now see much more clearly how it arises. Having to explain one's thoughts really helps clarify them. I was about to concede that perhaps you couldn't extract the conclusion from the evidence. I knew I was conceptualizing evidence and conclusions correctly but had doubts because I was not able to clearly verbalize the concepts.

But, upon further contemplating, I have quashed those doubts. I edited my previous post to add further clarity and again am confident I am conceptualizing evidence and conclusions correctly. They are separate entities.

And it isn't that I didn't take time to read the first page of posts here, it's that I was already in the middle of this very conversation with Beth, Piscivore, and Mobyseven (with articulett offering and occasional comment) in the other thread.

So, now I'll go back over the first page. That is, after I get a glass of wine....

 

[Skeptic Ginger]

...
Huh? It is evidence for the theory that there are fairies but not convincingly so because it could also be evidence of 1) lying 2) delusion 3) deception etc....

Which is essentially saying it could be evidence of. It is not saying it is evidence of.

 

[Skeptic Ginger]

.
Seeing a fairy proves their existence to that person. But people see fairies and UFOs all the time, and there's still no proof of either.

The individual's conclusion still doesn't alter the actual evidence and make it become evidence of fairies.

.Where I live, people have seen mountain lions walking thru the neighborhood in the night. No photos though.
There are a couple of indications that these are real sightings.. the people making the reports aren't hysterics, the number of feral cats in the neighborhood has diminished a lot, and, I've taken photos of footprints of very large cats where these lions have been reported.
I believe there are lions in the area, but what they are existing on, other than loose pets is a puzzlement. The neighbors who are aware of the reports don't seem to mind letting their veal...oops. kids, run around in the desert unsupervised where the lions are.
Possibly like a UFO on the White House lawn being the only acceptable proof of one, losing a kid proves there's lions out back.

[sidetrack]Where do you live?

Cougar Shot and Killed in Roscoe Village [North Chicago]Last Edited: Tuesday, 15 Apr 2008

"Captured cougar is 'fat and sassy,' " read the headline in the Aug. 28, 1981, edition of the P-I.

The 2-year-old male was nicknamed "D.B. Cougar" by the local media after the animal eluded police, K-9 units and even a posse of cat hunters five days after it was spotted in a Magnolia backyard in August, 1981 -- leading officials to rope off and close sections of Discovery Park.

A state game officer's cry of "cougar hysteria" was drowned out by panic after police themselves spotted the cat and the park's chief ranger, Paul Frandsen, held up a plaster cast of its paw print for all to see. Less than a day later, still baffled by how a wild animal got into Seattle in the first place, they got him.

Cougar euthanized after pet goat killed near Carnation, [WA]

In January, the same cougar was captured, outfitted with a radio telemetry collar and released in a wooded area north of Interstate 90, after it was discovered in a tree in the backyard of a home near Lake Meridian, outside Kent.

Over the last two months, WDFW biologists have tracked the cougar by following radio signals from the collar, monitoring the animal as it moved through open spaces, greenbelts, stream corridors and wetland forests in the Issaquah-Sammamish Plateau and industrial timberlands in eastern King County.

Cougar Attacks Increasing in West

Now consider the cougar that ate Wes Collins' dog:

It emerged from the forest behind the Collins house one evening in May and zeroed in on Sandy, the family's 50-pound Labrador mix. As two of Collins' children watched from the doorway, the cougar chased Sandy around the house and cornered her by the back deck. ...Collins' house sits on 5 acres outside Issaquah, where Seattle's suburban sprawl gives way to the forested Cascade foothills

The dog belonged to a friend of mine, the Issaquah Fire Chief at the time. The cougar took the dog from their backyard while the kids were there. These encounters used to be extremely rare. I only saw a cougar in the wild once and I've spent lots of time in the back country. But in the last decade or so, we have just built one too many housing tracts into their shrinking habitat.


Further U.S. and Canadian Cougar Encounters [/sidetrack]

 

[Dragoonster]

Not really buying some of these replies.

There being fairies is one possible pre-established theory. Belief isn't needed prior to the witnessing event. Let's say someone has a very good expectation of what a fairie would look like. If he sees something similar to it, it is evidence of fairies (yes, among other things). The only question is how strong the evidence is; in this case how closely it matches his expectations, or how closely it matches alternate theories that it would fit.

But it wouldn't even necessarily be a conclusion, much less is the evidence altered by the conclusion. The proper conclusion would be "I saw something that looked a lot/little/exactly like what I expected a fairie to look like, and it constitutes fair/weak/strong evidence as to the Theory of Fairies". Maybe if he believes it's strong enough he'd conclude that fairies probably do exist, or at least that it strongly helps the theory. Maybe he's wrong; being right or wrong or biased or unbiased isn't relevant if the witness is correctly measuring the value of the evidence. Only if it bore no resemblance to a theoretical fairie would it not be evidence at all.

The nature of the evidence has to be consistent--either all anecdotal evidence is valid (subject to strong/weak), or all is invalid. Neither a skeptic nor non-skeptic can cherry-pick what constitutes "evidence" itself based on how reasonable a conclusion/theory is.

Take the Face on Mars, both low and hi-res images. Either it was both evidence for and against (or not-for) the "anthropomorphic Mars civilization" or it wasn't/isn't evidence at all. It can't only become evidence once it meets a skeptic's theory.

 

[Skeptic Ginger]

...Which is why we can agree that it is unlikely that a fairy sighting demonstrates the existence of fairies. However, it is still evidence for fairies (even if it is also evidence for hallucinations, illusions etc).

Let's say for the sake of clarity in this discussion, that it is a given there is no evidence for fairies.

Yet you are accepting the person's conclusion (which you know to be completely unreliable considering there really is no evidence of fairies) as the evidence. No one else made these observations except other unreliable people making similar claims. Did any evidence for fairies actually ever exist here? Or do you simply have a lie, hallucination, or misinterpretation of some visual stimuli?

 

[Skeptic Ginger]

....
Again, I totally agree. Which is why we need to take care when communicating skepticism that we avoid statements such as 'there is no evidence for X'. Evidence is only useful in the context of other pieces of evidence, and in the context of how strong it is. I feel many people lack the skills in evaluating this weight, lending more credibility to personal anecdote or popular opinion than is due.

While there is a whole other topic called persuasion and the science of communication as I also refer to it, when it just comes down to the facts, of course one can say, "there is no evidence for X". Because sometimes it is a true statement. Why would you leave it out of your vocabulary?

Cool. I was beginning to think I was alone in this view.

Athon

I think the majority are in your camp. But I will not be deterred when I know my logic is impeccable!

 

[Skeptic Ginger]

I don't see a problem with the definition of "evidence" so much as with a lot of people not being clear on how to judge the strength of one particular kind of evidence as compared with another....

Put in general terms, anecdotal evidence certainly is a kind of evidence, but it's inherently a weak form of evidence because by itself it is uncorroborated by any sort of replicable correspondence with reality.

Anecdotes are evidence as in the specific examples I noted a couple posts back. And validity of any evidence is important.

But those two little prepositions, OF and FOR separate the noun, 'evidence', from the object of the preposition, of or for 'what'.

Evidence is nothing more than an indication of some sort that some particular thing, process, or phenomenon exists in nature. We can have that indication from testimony, from direct observation, or from indirect observation of phenomena suspected to be related to that
thing, process, or phenomenon. The strength of any given form of evidence is determined
by whether or not it has been tested against reality, and if so, how closely it seems to correlate with reality.

Evidence is what one uses to indicate as you say, but that indication is really an observation of the evidence and a conclusion about what the evidence indicates. The evidence - indicates... noun - verb. While you can use the word evidence as a verb, I don't think that is what we are talking about here and it certainly wouldn't exclude using the word, evidence, as a noun.

Seeing a fairy is one form of very weak evidence in favor of the existence of fairies. Stronger evidence would be multiple observations of fairies under controlled, objective circumstances; positive physical testing on the properties of fairies; or perhaps the capture of a fairy which could then be studied physiologically.

Absent any of this additional corroboration, a single anecdotal report of the observation of a fairy would probably be best explained by either non-fiary hypotheses, or if none of those seem to fit all the facts, by treating it as an anomalous occurance, currently unexplained, and waiting for a replication of the observation and additional data.

It isn't 'weak evidence', it is not evidence of fairies by any stretch. The interpretation of whatever the actual evidence is, be it an hallucination or fantasy, does not alter what the evidence actually is. A false conclusion about evidence does not create evidence for the false conclusion.

 

[Skeptic Ginger]

But that's putting the conclusion before the evidence. It's starting with the assumption that fairies don't exist and therefore the evidence can't be in support of it. If fairies did exist, seeing one would be evidence for it, surely?

Actually, you are assuming conclusions about anything cannot be drawn. I've looked at all the evidence of fairies starting with the photography hoax of a century ago and the implausibility of fairies existing in the natural world. Should evidence emerge that supports the existence of fairies, I can always reassess. But in the meantime, I have no trouble with the statement, "evidence of fairies is non-existent".

Now, it is incredibly unlikely that fairies exist, however if science is about accumulation of relative evidence then claiming something is not evidence simply because we have already concluded it isn't real is putting the cart before the horse.

I guess it comes down to agreeing whether an observation can only be evidence for one thing or for many other things.

Athon

You don't have to conclude there will never be any future evidence in order to say there is no current evidence. And you can at some point say there is sufficient evidence to say with certainty that claims of seeing fairies is not evidence of fairies. Perhaps in the future, you might revise that conclusion. But even without the benefit of being able to prove the non-existence of something like fairies in this case, you should have no trouble making a declaration that you will not accept someone's claim of seeing fairies as accurate and/or truthful. In that case you do not have evidence of fairies, you have someone else's conclusion about some evidence you are not observing.

If they produce a video, then you can say it might be evidence of fairies. Anything else is not evidence, it is a person's conclusion. The video can even be unlikely evidence with a more plausible explanation of hoax as in Ivor's example. But the claim a person makes is a conclusion and conclusions are not evidence.


Even in research, if one is using a previous study, one must be careful that the study actually supports the conclusion. It is an easy mistake to make. I'll try to drum up an example where the conclusion is not supported therefore citing the conclusion is not valid even if the research was.

 

[Skeptic Ginger]

....
I guess a simpler way of putting it is that we can't state definitively that fairies do not exist (you can't prove a negative), so you also can't definitively say that seeing one cannot be evidence of one existing.

Athon

By this position, you would also have to say then that you cannot definitively say any X is not evidence of Y. Well, I can say that. The inability to prove a negative does not apply here.

You are not saying you have proved fairies do not exist. You are saying you can prove Chester is lying or hallucinating. There is no scientific reason you cannot prove that. You may be applying previous evidence to Chester's claims, but scientifically there is nothing prohibiting you from proving Chester's conclusion is not evidence of fairies. If we had Chester's evidence to examine directly, that might be another story.

 

[athon]

Let's say for the sake of clarity in this discussion, that it is a given there is no evidence for fairies.

Yet you are accepting the person's conclusion (which you know to be completely unreliable considering there really is no evidence of fairies) as the evidence. No one else made these observations except other unreliable people making similar claims. Did any evidence for fairies actually ever exist here? Or do you simply have a lie, hallucination, or misinterpretation of some visual stimuli?

I'm not sure what you're meaning here, however it might be in hindsight as my wording has evolved through the thread. One of the pitfalls of responding to posts in the sequence of a thread is that they do not take into account the changing of a person's position as they learn more throughout a thread (although I can understand that probably doesn't happen much around here with some people ).

My use of the term 'fairy' in describing an observation is presumptive, and forces the conclusion that this was indeed what they saw. Which is, I concede, incorrect. I would be more correct to state 'a person observes a small flying humanoid traditionally matching the description of a fairy'.

My second error is in the vagueness of the term 'fairy', which is not a concise model describing flying humanoids but rather a varying cultural icon. I was seeking to describe a situation which is not accepted to have any evidence while showing an observation could be made which is technically called 'evidence', even if it is weak and attributable to other rationalisations.

Now, seeing a flying humanoid is most probably due to a hallucination. No argument there. However, to paraphrase, certainty is the realm of religion and politics. We accept that the observation is a hallucination only because it fits perfectly with a number of other observations. However, I suggest it still is evidence for an actual entity external to that person's subjective perception (I hesitate now to use the term 'fairy' for all of its connotations). It is weak evidence which does not shift the conclusion from 'hallucination', however the term evidence can still be applied to it.

To not call it evidence is to risk a circular argument.

'It is not evidence of a 'fairy' because 'fairies' aren't real.'
'How do you know they aren't real?'
'There is no evidence in support of them.'

In reality, applying science (IMO) properly, it is more accurate to say;

'It is weak evidence for a fairy, as there are better models for which it can be evidence of.'

Athon

 

[athon]

By this position, you would also have to say then that you cannot definitively say any X is not evidence of Y. Well, I can say that. The inability to prove a negative does not apply here.

You are not saying you have proved fairies do not exist. You are saying you can prove Chester is lying or hallucinating. There is no scientific reason you cannot prove that. You may be applying previous evidence to Chester's claims, but scientifically there is nothing prohibiting you from proving Chester's conclusion is not evidence of fairies. If we had Chester's evidence to examine directly, that might be another story.

Again, the nature of the language is what gets us into trouble here.

'Proof' is an absolute term with mathematical meaning that is not translated into science at all well. We cannot 'prove' in science; we can only supply sufficient weight of evidence that gives one the confidence to accept one model over another, with view that the provision of new evidence could cause such confidence to change.

By that, I can state categorically that we cannot 'prove' anything about Chester. We can only evaluate the evidence and arrive confidentally at a conclusion on which explanation is most useful.

Athon