Proving a negative?

[JustAnotherSkeptic]

Hi everybody! I've been lurking a while, but this is my first post.

I've been running this "can't prove a negative" thing through my head for a while, and I wanted to get other's opinions. Let's take a standard example:

The easter bunny doesn't exist.

Can't prove that, cause it's a negative, right? So, turn it around:

The easter bunny does exist.

Easy to prove, just present ole big ears himself and your all set.



Ok, but now this is where I get myself confused:

A falling object doesn't always go down.

That's a negative, but it's just as easy to prove as our last positive statement. Just show your object that's falling up and you've proven it. And the converse, positive statement, seems like the non-provable one:

A falling object always goes down.



On reflecting on all this, it seems to me that it's not a negative that you can't prove but a 'universal'. Anybody have any thoughts?

(oh, and, btw, I'm psychic, I've seen bigfoot, and I can cure any desease with my aura. :D)

[jmercer]

One problem is that in the EB situation you're citing a specific, and in the second case (falling up), you're citing a possibly infinite set of events looking for an exception.

Also, remember - assuming sapience on the part of the EB, unless you have a way of coercing appearance of a magical being, it's also not possible to demostrate that it exists... similar to the God problem. :)

[jmercer]

Also, "Falling up" is kinda poor terminology - you might want to rethink it to be more specific, because falling is always down by definition.

[JustAnotherSkeptic]

Originally posted by jmercer
[B]One problem is that in the EB situation you're citing a specific, and in the second case (falling up), you're citing a possibly infinite set of events looking for an exception.


Exactly. That's sort of the meat of my ponderings. Isn't it the infinite set of events you talk about that is the non-provable situation, not the inherent negation of a claim? It's just that it seems the two often become the same thing.


Also, remember - assuming sapience on the part of the EB, unless you have a way of coercing appearance of a magical being, it's also not possible to demostrate that it exists... similar to the God problem. :) [

Yes, you've got me there. But I was just trying to use the EB as a logical stand in. In other words, taking it for granted that I've met whatever criteria of evidence you'd need to for the EB, I've proven his existance by meeting that criteria.


falling is always down by definition


Ok... true. But that's really getting off on a tangent to what I was trying to get at. I was wondering about my logical questions, not really whether my ability to provide examples couldn't be picked apart :-)

(Sheesh, not even a 'welcome to the forum'. This place is tough ;))

[John Jackson]

It is possible to prove a negative as long as the proof involves detectable properties.

“My pen is not red�, or “there is not a telephone on my desk�, are easy to prove.

There are no photons emitting from my torch – provable, as photons are detectable.

I am not sending out telepathic messages – not provable, as telepathic messages cannot be detected.

The problem with paranormal claims is that people cling to them because they haven’t been disproved; but, of course, it’s not possible to prove that something doesn’t exist if indeed it does not. This results in claims like, “PSI phenomena have never been disproved� actually being meaningless.

[John Jackson]

Oh, and welcome to the forum. :D

[jmercer]

Originally posted by John Jackson
Oh, and welcome to the forum. :D

Oops! Ditto. :)

[JustAnotherSkeptic]

The problem with paranormal claims is that people cling to them because they haven’t been disproved; but, of course, it’s not possible to prove that something doesn’t exist if indeed it does not. This results in claims like, “PSI phenomena have never been disproved� actually being meaningless.
Yes, absolutely. There are lots of reasons not to try and disprove somebody's claim, such as what I believe you're stating- that disproving existence of something (what I called above 'proving a universal') is impossible. And, of course, it's not your burden to disprove what somebody else is claiming. If they want others to believe them, the onus is on them...

I've got some good replies from you guys, thanks! Where I was going with all this is that it's always bothered me when I hear people repeat the mantra "You can't disprove a negative." Firstly because it just never rang true in that simplified form, since the original intent was really, "You can't disprove the existence of something", which is a much different statement. And secondly because when said, it basically accepts the burden of proof inherently, and moves on to "I would prove it if I could, but I can't." That, to believers, sounds like a cop out.

To the statement, "You can't prove it's not true", I much prefer the statement, "I'm not attempting to prove anything one way or the other. It's YOU who are trying to prove something. So let's see it."

[MRC_Hans]

Originally posted by JustAnotherSkeptic
Hi everybody! I've been lurking a while, but this is my first post.

Well, welcome out of the lurking closet :).

I've been running this "can't prove a negative" thing through my head for a while, and I wanted to get other's opinions. Let's take a standard example:

The easter bunny doesn't exist.

Can't prove that, cause it's a negative, right? So, turn it around:

The easter bunny does exist.

Easy to prove, just present ole big ears himself and your all set.

Precisely.

Ok, but now this is where I get myself confused:

A falling object doesn't always go down.

That's a negative, but it's just as easy to prove as our last positive statement. Just show your object that's falling up and you've proven it. And the converse, positive statement, seems like the non-provable one:

A falling object always goes down.

#1 is not falsifiable. You can prove that it is true by presenting an object that falls up, but that is proving a positive (namely "an object exist that does not fall down"), but you cannot prove a negative, because you cannot prove that no object exists anywhere in the universe that will fall up.

# 2 is a positive statement, and it is falsifiable. But difficult to falsify.

On reflecting on all this, it seems to me that it's not a negative that you can't prove but a 'universal'. Anybody have any thoughts?

Both are right, or nearly: You cannot prove a negative, and it is often virtually impossible to prove universality.

(oh, and, btw, I'm psychic, I've seen bigfoot, and I can cure any desease with my aura. :D)

Bigfoot is my uncle, say hello to him from me.

Hans

[MRC_Hans]

Originally posted by John Jackson
It is possible to prove a negative as long as the proof involves detectable properties.

“My pen is not red�, or “there is not a telephone on my desk�, are easy to prove.

There are no photons emitting from my torch – provable, as photons are detectable.

I am not sending out telepathic messages – not provable, as telepathic messages cannot be detected.

The problem with paranormal claims is that people cling to them because they haven’t been disproved; but, of course, it’s not possible to prove that something doesn’t exist if indeed it does not. This results in claims like, “PSI phenomena have never been disproved� actually being meaningless. Detectable properties AND a closed logical system. For instance your torch: There are only two possibilities: It emits photons, or it doesn't, so positive evidence for one falsifies the other. Incidentially, your torch emits photons whenever its temperature is above 0K ;).

You are quite right about paranormal phenomena.
Hans

[jmercer]

Originally posted by JustAnotherSkeptic
Exactly. That's sort of the meat of my ponderings. Isn't it the infinite set of events you talk about that is the non-provable situation, not the inherent negation of a claim? It's just that it seems the two often become the same thing.


Mmm... yes and no. There are negatives that can be proven, but they all resolve themselves as material actions, objects, or phenomena. Infinity does throw a monkey wrench into the idea, because it's impossible to demonstrate an infinite set.

However, unique events are also often inherently unprovable as a negative because they're unique and can't be repeated or observed; such as a claim that "Jesus Christ did not rise from the dead", etc..

Originally posted by JustAnotherSkeptic

Yes, you've got me there. But I was just trying to use the EB as a logical stand in. In other words, taking it for granted that I've met whatever criteria of evidence you'd need to for the EB, I've proven his existance by meeting that criteria.


Very true, assuming that the criteria is agreed on. I understand what you're driving at - but I don't have any answers for you other than the suggestion to not use a magical being in the discussion because it really creates some serious problems with defining proof.

Originally posted by JustAnotherSkeptic

Ok... true. But that's really getting off on a tangent to what I was trying to get at. I was wondering about my logical questions, not really whether my ability to provide examples couldn't be picked apart :-)


I gotcha. :) In a way, though, our ability to define the problem affects the likelyhood of resolving the question... language for these discussions is really critical, because it's so easy to assume we're both talking about "apples". :)

Originally posted by JustAnotherSkeptic

(Sheesh, not even a 'welcome to the forum'. This place is tough ;))

Yeah, I do apologize - I didn't notice this was your first posting. And you really are welcome here. :)

[John Jackson]

Originally posted by MRC_Hans
Incidentially, your torch emits photons whenever its temperature is above 0K ;). :p

You've found the word I should have used: "falsifiable".

If a claim is not (potentially) falsifiable, it is rendered meaningless.

[Paul C. Anagnostopoulos]

Welcome! :D

I try to say "It's difficult to prove a universal negative." You can prove "There is no elephant in my living room." You cannot prove "There is no elephant anywhere."

And, as everyone has said, watch out for false dichotomies: There are problems with evolution, so ID must be true. No one will say it that directly, but they're saying it nonetheless.

And never waste your time trying to disprove an anecdote from a believer, unless you can find a logical flaw in it.

~~ Paul

[H3LL]

Deleted post as Paul said the same thing in less words.

[jmercer]

Originally posted by John Jackson
:p

If a claim is not (potentially) falsifiable, it is rendered meaningless.

Is that really true, though? For example, quantum theory states that one can know the exact velocity or the exact position of a particle - but not both simultaniously. I don't know how you'd falsify that claim, but it's not meaningless.

Also, there's the so-called "observer" effect where the act of measuring the state of a particle supposedly defines it's state. There's no way to actually prove or disprove that claim (by definition!), but there's a commercially available encryption process that makes use of this property.

I'm playing devil's advocate here, but I think it's important to be careful when making absolute statements. :)

[Santa666]

Though no one has brought it up as an example. I would like to interject that I do, in fact, exist.

HO HO HO, Merry Xmas.

That damn bunny is always trying to one-up me for exposure.


Santa

[Paul C. Anagnostopoulos]

jmercer said:
Is that really true, though? For example, quantum theory states that one can know the exact velocity or the exact position of a particle - but not both simultaniously. I don't know how you'd falsify that claim, but it's not meaningless.
I believe you can prove Heisenberg:

http://www.cbloom.com/physics/heisenberg.html

It's one of the most misunderstood concepts in all of physics.

~~ Paul

[c4ts]

Originally posted by Santa666
Though no one has brought it up as an example. I would like to interject that I do, in fact, exist.

HO HO HO, Merry Xmas.

That damn bunny is always trying to one-up me for exposure.


Santa

You really ought to send an elf hitman to fix him.

[Nex]

Originally posted by Paul C. Anagnostopoulos
[...]It's one of the most misunderstood concepts in all of physics.
Gee, I can't fathom why. What is that, ancient Greek? :p

[Jeff Corey]

No, it's six feet.

[c4ts]

Originally posted by Jeff Corey
No, it's six feet.

|6'| < or = 2DADB ?


Huh?

[Francois Tremblay]

Proving universal negatives is not only POSSIBLE, but NECESSARY. It's what the scientific process does. We confirm propositions by falsification - by showing what is not so - and looking at what's left.

People who say we can't disprove things, are denying the scientific process itself.

[c4ts]

Originally posted by Francois Tremblay
Proving universal negatives is not only POSSIBLE, but NECESSARY. It's what the scientific process does. We confirm propositions by falsification - by showing what is not so - and looking at what's left.

People who say we can't disprove things, are denying the scientific process itself.

So how is it done?

[hodgy]

Originally posted by jmercer
Also, "Falling up" is kinda poor terminology - you might want to rethink it to be more specific, because falling is always down by definition.

I bought a helium ballon for my 2 year old son the other day and to my surprise - it fell up :)

[c4ts]

Technically it didn't fall up, the atmosphere around it fell and the far less dense balloon was forced upwards by the pressure.

[TobiasTheCommie]

Originally posted by c4ts
Technically it didn't fall up, the atmosphere around it fell and the far less dense balloon was forced upwards by the pressure.
spoilsport.

[delphi_ote]

Originally posted by JustAnotherSkeptic
I've been running this "can't prove a negative" thing through my head for a while, and I wanted to get other's opinions. Let's take a standard example:

The easter bunny doesn't exist.


I think it's means proving the non-existence of something or proving that there's no evidence for something.

Negatives are proven all the time. This phrase is just abused too much.

[jmercer]

Originally posted by Francois Tremblay
Proving universal negatives is not only POSSIBLE, but NECESSARY. It's what the scientific process does. We confirm propositions by falsification - by showing what is not so - and looking at what's left.

People who say we can't disprove things, are denying the scientific process itself.

The scientific process isn't about "proving universal negatives", or anything else like that. It's a methodology for testing specific hypotheses, which are either proven or disproven during the testing.

The scientific process (as taught to virtually every high-school student)

1) Identify the problem or question which is the central point of your scientific investigation.

2) Develop a hypothesis. A hypothesis is an educated guess which is specific and testable.

3)Test the hypothesis. The procedure must be designed to answer the specific problem.

4) Evaluate the data. Once you have finished your experiment, you must determine if the data collected answers the hypothesis. Often the data is unconvincing or the hypothesis is disproved. When this happens you might need to think of a new procedure for your experiment or a new hypothesis.

What something more formal? (http://teacher.nsrl.rochester.edu/phy_labs/AppendixE/AppendixE.html)

1. Observation and description of a phenomenon or group of phenomena.

2. Formulation of an hypothesis to explain the phenomena. In physics, the hypothesis often takes the form of a causal mechanism or a mathematical relation.

3. Use of the hypothesis to predict the existence of other phenomena, or to predict quantitatively the results of new observations.

4. Performance of experimental tests of the predictions by several independent experimenters and properly performed experiments.

Show me, Francois, where "proving universal negatives" is a part of the scientific process... or even a stated goal of it. Any definition from any reliable authoritive source will do.

[MRC_Hans]

The "you cannot prove a negative", is also to be viewed as a rule of debate. In this context, it should really be: You cannot require anybody to prove a negative.

And here it does not matter if that particular negative happens to be a provable one; what matters is that you cannot enter a claim into a debate and require to other part to prove you wrong. Whoever enters a claim has the duty to provide evidence for it.

Hans

[athon]

Originally posted by MRC_Hans
The "you cannot prove a negative", is also to be viewed as a rule of debate. In this context, it should really be: You cannot require anybody to prove a negative.

And here it does not matter if that particular negative happens to be a provable one; what matters is that you cannot enter a claim into a debate and require to other part to prove you wrong. Whoever enters a claim has the duty to provide evidence for it.

Hans

Good thing I read all the way to the end; I was going to say the same thing.

Proving a negative depends on the situation, as has been shown here. It depends on the parameters defining the system and the definitions of the statements requiring evidence.

Firstly 'proof' is a mathematical term, not scientific. Proving something in science is subjective as it relies on a personal level of evidence a person might be satisfied with. Hence the statement should be 'you cannot provide evidence for a negative'.

This raises the old debate 'is absence of evidence the same as evidence of absence?'. Part of the argument here will rest on 'within what system?'.

If I draw a circle on the ground and say 'there is no rabbit inside the circle', you can be satisfied that the absence of a rabbit according to your eyes suffices as ample proof. Make that circle larger, and it will slowly get to the point where you will have to use inductive reasoning (most of the circle has no rabbit, therefore I will assume that the rest has no rabbit as well). Past a certain point, that will not stand as an argument either as searching the circle is impractical.

The typical run of the debate often relies on a claim for the positive being addressed. If I say 'The Easter Bunny does not exist', I am really claiming 'I have not yet seen evidence supporting any claim that EB exists'. Definitions are the biggest tripping point.

Athon

[MRC_Hans]

Originally posted by athon
*snip*
The typical run of the debate often relies on a claim for the positive being addressed. If I say 'The Easter Bunny does not exist', I am really claiming 'I have not yet seen evidence supporting any claim that EB exists'. Definitions are the biggest tripping point.

Athon Enter the "working assumption", another point believers often get wrong. So you say the Easter Bunny does not exist. This does not mean that you have positive proof of its non-existence, nor does it mean that you think absense of evidence is evidene of absense. It simply means that you observe that the idea is illogical, has no evidence to support it, and all observations of the alleged activities of the EB have more parsimonious explanations. So, till such time as evidence for the EB is presented, you have decided to leave it our of your world-picture.

Hans

[jmercer]

Athon, Hans - I completely agree, and that was well written. The thing that bugs me the most about when people who have chosen to leave something out of their worldview forget that it's a choice on their part, and argue about it as if it's a proven fact.

In my case, I choose not to believe in the EB; if I met an adult who believed in the EB and wanted to debate it, I'd present my argument based on my logic and any pertinent facts. I wouldn't, however, simply take the position "This is nonsense. The EB doesn't exist." regardless of what I believe the truth is based on my understanding of the facts. Because if I make a claim - "The EB doesn't exist" - I then can be asked to prove it, which may be beyond my abilities.

[MRC_Hans]

Actually, that's a good point. Believers often say "You claim [insert belief system] is wrong, so you must prove your claim". While this is, technically, a fallacy, it is not entirely unreasonable. Whoever seeks the debate has a duty to provide evidence for his/her position, even if it is a negative one.

Hans

[Ashles]

Originally posted by MRC_Hans
Actually, that's a good point. Believers often say "You claim [insert belief system] is wrong, so you must prove your claim". While this is, technically, a fallacy, it is not entirely unreasonable. Whoever seeks the debate has a duty to provide evidence for his/her position, even if it is a negative one.
I must disagree there.

Surely the whole JREF challenge is a position of asking someone to demonstrate their claim is true? It isn't up to Randi to prove the opposite position is true.

Similarly if I meet someone who makes a claim about something, it is surely not my requirement to disprove their claim, it is the original claim that must be proven.

I would find that attempt to shift the burden of proof entirely unreasonable.

When you say:
Actually, that's a good point. Believers often say "You claim [insert belief system] is wrong, so you must prove your claim".
This is misrepresenting the claims that are being made.
The claim that the belief system is wrong is not actually the important claim being made. In such a scenario, it is, in the first instance, the claim that the belief system is correct that is the main claim and the one that must be logically defended.

What evidence can we provide for our position other than that there is no evidence?

I am quite surprised to see you take this position after the number of times I have seen you ask homeopaths to provide evidence of their claims.

[jmercer]

Hi, Ashles - while you were addressing Hans, I just wanted to throw my own "2 cents in", as the saying in the US goes. :)

The JREF doesn't make any claims; they challenge them. If Randi made a negative claim - "Homeopathy doesn't work" - the Homeopaths of the world would be justified in saying "Prove it" - and proving that particular negative would be tough. There will always be an excuse about why the proof is incomplete, or a "special case exists", etc. However, critical thinking and skepticism should operate in an unbiased fashion; if a claim is made, it should undergo the same level of examination regardless of source.

I think this is why JREF doesn't actually make any claims, but instead created the JREF Challenge; the Challenge itself won't ever actually prove that woo-stuff doesn't exist. Instead, it creates an overwhelming record of failure regarding the claims that it does exist.

I guess I'm stating the obvious, but I believe the JREF uses this specific strategy in the hopes that those who are initially unsure about this stuff will eventually be won over. Because while it may be very difficult - or even impossible - to absolutely disprove something, there's a point where the proof becomes overwhelming. :)

Hm. I just realized something. JREF's entire strategy is based on "negative proof", or a "lack of proof"... interesting, I never really considered it in that context before. Good thread - thanks for starting it, JAS!

[Blondin]

Falling Up

I tripped on my shoelace
And I fell up--
Up to the roof tops,
Up over the town,
Up past the tree tops,
Up over the mountains,
Up where the colors
Blend into the sounds.
But it got me so dizzy
When I looked around,
I got sick to my stomach
And I threw down.

- Shel Silverstein

[delphi_ote]

But Randi DOES provide evidence that nonsense claims are nonsense. They violate the laws of physics as we understand them. They are easily faked by certain methods. Certain psychological phenomina are similiar to them.

Ultimately, the burden of proof is always on the person making a claim, but when they refuse and continue making their claim we have to present some kind of counter argument.

I'm suprised you brought up the homeopathy threads, Ash. Though the burden of proof was on the h'paths of course, but we constantly provided scientific observation as to why the entire system on which homeopahty is based is impossible according to all previous observations we have made about our world. That was what made them look more ridiculous than anything else.

[Ashles]

Originally posted by jmercer
The JREF doesn't make any claims; they challenge them. If Randi made a negative claim - "Homeopathy doesn't work" - the Homeopaths of the world would be justified in saying "Prove it" - and proving that particular negative would be tough. There will always be an excuse about why the proof is incomplete, or a "special case exists", etc. However, critical thinking and skepticism should operate in an unbiased fashion; if a claim is made, it should undergo the same level of examination regardless of source.
I don't see 'Homeopathy doesn't work' as a claim in the same way as 'Homeopathy does work' is a claim.

'Homeopathy doesn't work' (and any sceptical 'claim') is always going to be a response to an initial claim.

And most sceptical claims of this nature are based on the fact that there is no evidence for the initial claim.

Surely in such a debate the onus is firmly on the original claim (which will change scientific knowledge) to provide evidence. Without that a counterclaim is merely a request for evidence (or rather an illustration of the lack of evidence) put in a more strident way.

A claim that something doesn't work or doesn't exist, pretty much by definition, cannot ever have evidence, merely a lack of it.

Unfortunately that means (I would have thought) that in these cases we cannot use deduction, only induction to form conclusions. And of course that is very unsatisfactory. Hence the problem.
Thus it must always be up to the original claim to prove the existence as that is the only was we can ever reach a definitive conclusion.
The non-existence can only ever be assumed (albeit with very good reason).

[Ashles]

Originally posted by delphi_ote
I'm suprised you brought up the homeopathy threads, Ash. Though the burden of proof was on the h'paths of course, but we constantly provided scientific observation as to why the entire system on which homeopahty is based is impossible according to all previous observations we have made about our world. That was what made them look more ridiculous than anything else.
I know, but as we know, just because a theory appears to violate previously observed evidence, does not make it incorrect. If it works, it works and it would only mean that our current theories were incorrect.

The strongest evidence against homeopathy is not that it appears to violate current assumed science, but that it just doesn't work in any proper testing.

Scientific knowledge has been superceded too many times for us to assume that the fact that something appears to work in ways we don't understand means that it cannot exist.
While this is one of the arguments against homeopathy I don't think it is the strongest because if homeopathy really did work it would be obvious that our current theories were incorrect.
The fact that it doesn't work is its biggest logical downfall.

[jmercer]

Originally posted by Ashles
I don't see 'Homeopathy doesn't work' as a claim in the same way as 'Homeopathy does work' is a claim.

'Homeopathy doesn't work' (and any sceptical 'claim') is always going to be a response to an initial claim.

And most sceptical claims of this nature are based on the fact that there is no evidence for the initial claim.

Surely in such a debate the onus is firmly on the original claim (which will change scientific knowledge) to provide evidence. Without that a counterclaim is merely a request for evidence (or rather an illustration of the lack of evidence) put in a more strident way.

A claim that something doesn't work or doesn't exist, pretty much by definition, cannot ever have evidence, merely a lack of it.

Unfortunately that means (I would have thought) that in these cases we cannot use deduction, only induction to form conclusions. And of course that is very unsatisfactory. Hence the problem.
Thus it must always be up to the original claim to prove the existence as that is the only was we can ever reach a definitive conclusion.
The non-existence can only ever be assumed (albeit with very good reason).

Well, yeah. Which brings us around full circle to why proving a negative is so hard - and sometimes, impossible.

However, I have to quibble with you over one thing - a claim is a claim, regardless of source, prompting or situation. Just because saying "Homeopathy doesn't work!" is a skeptical reaction to people saying "Homeopathy does work!" doesn't make it any less of a claim. But as you say, it's clearly difficult to prove because it's a negative statement. ("doesn't work")

But I have to assert the one point that I'm not willing to yield - ANY claim is subject to the skeptical response "prove it" - including "Homeopathy doesn't work!" De rules are de rules. :D

I think that we may be just wrestling with semantics at this point.

[John Jackson]

Originally posted by jmercer
In my case, I choose not to believe in the EB; if I met an adult who believed in the EB and wanted to debate it, I'd present my argument based on my logic and any pertinent facts. I wouldn't, however, simply take the position "This is nonsense. The EB doesn't exist." regardless of what I believe the truth is based on my understanding of the facts. Because if I make a claim - "The EB doesn't exist" - I then can be asked to prove it, which may be beyond my abilities. Originally posted by MRC_Hans
Actually, that's a good point. Believers often say "You claim [insert belief system] is wrong, so you must prove your claim". While this is, technically, a fallacy, it is not entirely unreasonable. Whoever seeks the debate has a duty to provide evidence for his/her position, even if it is a negative one.

Hans

I agree with this point; at least where paranormal issues are involved.

To say, “homeopathy doesn’t work� is reasonable because in quality trials it cannot be shown to work. In other words there are some empirical data available to back up the claim.

A statement such as, “the afterlife doesn’t exist� however, is a different matter. The afterlife is (as far as I know) an unfalsifiable claim: whether in the positive or the negative. To claim to know that it doesn’t exist is to leave oneself open to the “prove it� challenge that we skeptics are so keen to issue to others.

Claims require evidence.

[tsg]

Originally posted by Ashles
I know, but as we know, just because a theory appears to violate previously observed evidence, does not make it incorrect. If it works, it works and it would only mean that our current theories were incorrect.

The strongest evidence against homeopathy is not that it appears to violate current assumed science, but that it just doesn't work in any proper testing.

Scientific knowledge has been superceded too many times for us to assume that the fact that something appears to work in ways we don't understand means that it cannot exist.
While this is one of the arguments against homeopathy I don't think it is the strongest because if homeopathy really did work it would be obvious that our current theories were incorrect.
The fact that it doesn't work is its biggest logical downfall.

The problem with testing is that it can only show that it didn't appear to work in this particular instance. Every effort can be taken to eliminate as many variables as possible, but there will always be some that can't be eliminated. It may be entirely possible that only people with a certain characteristic respond well to homeopathic treatments that none of the tests attempted to isolate. The amount of science that would have to be wrong, however, for homeopathy to work is pretty staggering. There is enough evidence to refute the claims of why homeopathy works to make it reasonably certain that it can't. The tests where homeopathy failed are just icing on the cake. A failed test is simply "absence of evidence", in other words, the best a test can say is "the test doesn't support the claim". The science refuting homeopathy is "evidence to the contrary", which is much stronger. A test showing homeopathy to work would also have to explain why the evidence against it working is incorrect.

[tsg]

Originally posted by jmercer
Well, yeah. Which brings us around full circle to why proving a negative is so hard - and sometimes, impossible.

However, I have to quibble with you over one thing - a claim is a claim, regardless of source, prompting or situation. Just because saying "Homeopathy doesn't work!" is a skeptical reaction to people saying "Homeopathy does work!" doesn't make it any less of a claim. But as you say, it's clearly difficult to prove because it's a negative statement. ("doesn't work")

But I have to assert the one point that I'm not willing to yield - ANY claim is subject to the skeptical response "prove it" - including "Homeopathy doesn't work!" De rules are de rules. :D

I think that we may be just wrestling with semantics at this point.

As a rule, I try to refrain from making claims like "X doesn't exist/work" and rather state "there is little evidence that X exists/works and plenty that shows why it shouldn't". In some cases, I'll go so far as to say "everything we know about [physics|chemistry|astronomy|etc.] says that it can't". Both put the onus on the claimant to support his claim.

[Ashles]

Originally posted by jmercer
I think that we may be just wrestling with semantics at this point.
Mostly yes.

But tsg ilustrates one point I think is important about the fact that a failed test only means that it failed in that particular instance (a huge part of the homeopaths' defence).

Science should work by observations then tests, but paranormal and pseudoscience claims often work by someone misinterpreting something and then formulating theories which are untestable, or fail testing. But the theories still endure.

Saying that all claims are equal puts scepticism in an impossible situation because it cannot ever hope to come to conclusions.
And I honestly don't think it is true.
Nobody here genuinely thinks the IPU exists or that we should expend any effort in analysing any claims relating to it. Why? Because there are degrees to which lack of evidence are overwhelming.
If I say the IPU doesn't exist it would not be seriously challenged by anyone. No requests for proof would be required.
So what claims require evidence is a matter of degree, not an absolute.

If there is no logical reason for us to believe a thing is true in the first instance, why is it an equal claim to say that thing doesn't exist?
Surely non-existence should be the default position of anything until we have an actual reason to think it exists in the first place.

[jmercer]

Originally posted by Ashles
Surely non-existence should be the default position of anything until we have an actual reason to think it exists in the first place.

Agreed. :)

[tsg]

Originally posted by Ashles
Saying that all claims are equal puts scepticism in an impossible situation because it cannot ever hope to come to conclusions.
And I honestly don't think it is true.

This a particular pet peeve of mine: the idea that all opinions are equally valid, even those which are entirely uninformed or demonstrably wrong. It's also a wedge that psuedoscience uses to give validity to their claims. ID in particular uses "evolution isn't proven" as an argument that their "theory" is just as valid, ignoring, of course, the mountains of evidence supporting one theory and no real evidence supporting the other.

If there is no logical reason for us to believe a thing is true in the first instance, why is it an equal claim to say that thing doesn't exist?

It's a matter of semantics. "There is no reason to believe that X exists" (or even "there is good reason to believe it doesn't exist") and "X doesn't exist" differ in one respect: the former suggests that, should sufficient evidence be produced, the claim will have validity (and places the obligation of supporting the claim on the claimer) while the latter suggests (to me, anyway) a claim of "it isn't possible" that places the obligation of proof on me. It's the difference between "it's unlikely" and "it's not possible". I can't say for certain that free-energy devices can never work, but I have plenty of reasons to believe it very unlikely that they can.

Surely non-existence should be the default position of anything until we have an actual reason to think it exists in the first place.

I see it like this: Science says "why?" Pseudoscience says "why not?" For some, the possibility of a claim being true is enough for them to believe in it regardless of whether or not it has actually been observed.

[jmercer]

Originally posted by tsg
I see it like this: Science says "why?" Pseudoscience says "why not?" For some, the possibility of a claim being true is enough for them to believe in it regardless of whether or not it has actually been observed.

I liked your post in every way, except for this last sentence. Science doesn't concern itself with "why"; that's the realm of philosophy. Science concerns itself with "how". :)

Pseudoscience tries to crossbreed philosophy with science. As a result, they get a series of sterile freaks, often stillborn.

[Ashles]

I agree with you both.

Interesting thread.:)

[John Jackson]

Originally posted by tsg
Science says "why?" Pseudoscience says "why not?"That's an excellent way to put it - I'll use that. Then copyright it. :p :D

For some, the possibility of a claim being true is enough for them to believe in it regardless of whether or not it has actually been observed.It's the classic argument to ignorance.

[tsg]

Originally posted by jmercer
I liked your post in every way, except for this last sentence. Science doesn't concern itself with "why"; that's the realm of philosophy. Science concerns itself with "how". :)

Pseudoscience tries to crossbreed philsophy with science. As a result, they get a series of sterile freaks, often stillborn.

I was speaking more in terms of "why?" and "why not?" responding to the statement "this should be believed".

[tsg]

Originally posted by John Jackson
That's an excellent way to put it - I'll use that. Then copyright it.

Feel free. But I have to warn you, I may have stolen it from somebody else.

It's the classic argument to ignorance

AKA, appropriately enough, "God of the Gaps".

[jmercer]

Originally posted by tsg
I was speaking more in terms of "why?" and "why not?" responding to the statement "this should be believed".

Ah. Fair enough, then. :)

[tsg]

Originally posted by tsg
It's a matter of semantics. "There is no reason to believe that X exists" (or even "there is good reason to believe it doesn't exist") and "X doesn't exist" differ in one respect: the former suggests that, should sufficient evidence be produced, the claim will have validity (and places the obligation of supporting the claim on the claimer) while the latter suggests (to me, anyway) a claim of "it isn't possible" that places the obligation of proof on me. It's the difference between "it's unlikely" and "it's not possible". I can't say for certain that free-energy devices can never work, but I have plenty of reasons to believe it very unlikely that they can.

Bad form, replying to my own post, I know, but there was something I didn't like about this when I wrote it and I figured out what it was. This gets a little philosophical, so please bear with me.

"There is no evidence that Y exists" is simply a claim in the form of "X doesn't exist" where X is "evidence that Y exists". So, fundamentally, there is no difference at all between the statements "X doesn't exist" and "there is no evidence that X exists". Both are claiming the non-existance of something, which is, by its very nature, unprovable. It is, however, extremely easy to disprove simply by showing X, whether X is the thing in question or the evidence that X exists. It is a claim, a falsifiable one, but also one that can't be proven on it's own.

From a less literal interpretation, though, I still prefer the statement "there is no evidence of the existance of X" to "X doesn't exist" for the reasons I stated above. In response to the claim "X exists" without any supporting evidence, I believe it to be a valid claim regardless of its supportability simply because the evidence of the existence of X should be the burden of the person claiming it.

I'm done rambling.

[jmercer]

Originally posted by tsg
"There is no evidence that Y exists" is simply a claim in the form of "X doesn't exist" where X is "evidence that Y exists". So, fundamentally, there is no difference at all between the statements "X doesn't exist" and "there is no evidence that X exists". Both are claiming the non-existance of something, which is, by its very nature, unprovable. It is, however, extremely easy to disprove simply by showing X, whether X is the thing in question or the evidence that X exists. It is a claim, a falsifiable one, but also one that can't be proven on it's own.

From a less literal interpretation, though, I still prefer the statement "there is no evidence of the existance of X" to "X doesn't exist" for the reasons I stated above. In response to the claim "X exists" without any supporting evidence, I believe it to be a valid claim regardless of its supportability simply because the evidence of the existence of X should be the burden of the person claiming it.

I'm done rambling.

Far be it from me to interfere with an argument amongst yourselves... ;) ... but I disagree. It's a logical fallacy to assume that a lack of evidence indicates anything other than a lack of evidence.

In example, there's tons of evidence that God exists. Sadly, it's all of highly questionable pedigree, and is strictly anecdotal, or weak. If we throw out that evidence because it doesn't meet our standards for such things, does that logically disprove the existence of God?

Nope.

All it does is eliminate a set of evidence concerning the existence of God that we find questionable. The burden of proof doesn't shift, of course; but the claimants would be correct to state that they supplied proof, which was ultimately rejected and discarded.

:)

[MRC_Hans]

Late reply, sorry...

Originally posted by Ashles
I must disagree there.

Surely the whole JREF challenge is a position of asking someone to demonstrate their claim is true? It isn't up to Randi to prove the opposite position is true.

That is correct. Randi says: Come and prove your claim, and you can win a prize. Perfectly legitimate. He invites the opposition to make a claim and support it.

Similarly if I meet someone who makes a claim about something, it is surely not my requirement to disprove their claim, it is the original claim that must be proven.

I would find that attempt to shift the burden of proof entirely unreasonable.Right, because they entered the debate making a claim. So the onus of proof is on them, period.

When you say:

This is misrepresenting the claims that are being made.
The claim that the belief system is wrong is not actually the important claim being made. In such a scenario, it is, in the first instance, the claim that the belief system is correct that is the main claim and the one that must be logically defended.

What evidence can we provide for our position other than that there is no evidence?

I am quite surprised to see you take this position after the number of times I have seen you ask homeopaths to provide evidence of their claims.Maybe I did not make myself sufficiently clear: In a debate, there is no doubt. But if I sort of barge in in somebody and tells him "your easter bunny does not exist!", then he has the right to say: "I have chosen to believe it does, but I have no need to prove it to you, you can believe what you will." ... He has a right to refuse the debate.

For homeopathy, Roger Coghill, Karen Boesen and others like that, it is a little different: They are not just entertaining a private, innocent belief, they have already entered the debate by imposing their claims on others, by basically offering their belief systems for sale, so THEY are fair game, IMHO.

That is what I meant ;).

Hans

[Paul C. Anagnostopoulos]

What Hans said. You make a public claim, you're fair game. That's what the marketplace of ideas is all about.

Hey, that rhymes.

~~ Paul

[tsg]

Originally posted by jmercer
Far be it from me to interfere with an argument amongst yourselves... ;) ... but I disagree. It's a logical fallacy to assume that a lack of evidence indicates anything other than a lack of evidence.

I never said otherwise. The point of my rambling was that "X doesn't exist" and "there is no evidence that X exists" are not logically different as I had originally thought. Both are a claim of non-existence of something, which cannot be proven.

Absence of evidence is not evidence of absence, but, contrary to the pleadings of the pseudoscientist, it is certainly not evidence of existence. The inability to disprove the existence of something only makes it possible. But "possible" does not mean "likely".

[jmercer]

Originally posted by tsg
I never said otherwise. The point of my rambling was that "X doesn't exist" and "there is no evidence that X exists" are not logically different as I had originally thought. Both are a claim of non-existence of something, which cannot be proven.

Absence of evidence is not evidence of absence, but, contrary to the pleadings of the pseudoscientist, it is certainly not evidence of existence. The inability to disprove the existence of something only makes it possible. But "possible" does not mean "likely".

Ah, ok - I got confused while reading it, I guess. :)

Too bad Interesting Ian's not here - he would have argued with you over your second paragraph. :D

"I'm arguing that the existence of fraudulent psychics makes the existence of genuine psychics more likely." - Interesting Ian

[tsg]

Originally posted by jmercer
Too bad Interesting Ian's not here - he would have argued with you over your second paragraph. :D

"I'm arguing that the existence of fraudulent psychics makes the existence of genuine psychics more likely." - Interesting Ian

I read that thread. Absolutely amazing.

If the existence of real psychics increases the number of fake psychics, then yes, the existence of fake psychics could make the existence of real psychics more likely than if there were no fake psychics. How much more likely is entirely dependent on how many fake psychics are the result of real psychics and how many other factors lead to the existence of fake psychics. Since the idea of real psychics is all that is necessary for the fake psychics to exist, and the existence of real psychics is not necessary for the idea to exist, "how much more likely" is "not much". So, technically, the claim you quoted is true, but misleading. However, if you go back and read the original post which spawned the argument, his claim was that real psychics "almost certainly" exist since fake psychics do. Clearly not the case.

It also ignores the possibility that the existence of real psychics would decrease the number of fake psychics since it would likely be harder to fake being a psychic. There are very few (if any) fake engineers because their designs wouldn't work and, having real engineers designs to compare them to, wouldn't stand up to scrutiny. They can't make infinite excuses as to why it doesn't work because the client simply points to another engineer's work and says, "how come his does?". And if real psychics aren't any more proficient than fake psychics, then it hardly matters if they do really exist.

[Bri]

Originally posted by tsg
I never said otherwise. The point of my rambling was that "X doesn't exist" and "there is no evidence that X exists" are not logically different as I had originally thought. Both are a claim of non-existence of something, which cannot be proven.


Very interesting thread! Just wanted to add a couple thoughts...

I agree with tsg's statement, so would the "correct" statement be "X has not been proven to exist" or "You have not provided overwhelming evidence that X exists" or "You have not provided more evidence [or more compelling evidence] of the existance of X than the evidence against X" or something similar? Of course, these are only statements in response to a claim that "X" exists. Any positive statement (one that isn't in response to another person's claim) other than perhaps "We cannot know for certain whether or not X exists" would still be a statement that requires evidence to back it up.

Originally posted by Ashles
Surely the whole JREF challenge is a position of asking someone to demonstrate their claim is true? It isn't up to Randi to prove the opposite position is true.

The JREF Challenge can prove specific claims to be false. For example, a dowser can be proven to not be able to provide evidence of his or her claims, but the Challenge does not attempt to prove dowsing to be false. That said, the JREF Challenge does provide evidence (perhaps even overwhelming and certainly compelling evidence) that dowsing isn't possible by demonstrating an enormous number of people who believe they can dowse and then fail their own tests. Does this disprove dowsing? Of course not, but it doesn't claim to. It does, however, provide some pretty convincing evidence that a lot of people out there who believe that they can dowse can't, and it also demonstrates that not a single one of these claims has ever provided evidence that dowsing works.

The homeopathy argument seems to work the same way. If it hasn't been shown to work in the hundreds of tests that have been done, then we can assume that it doesn't work until sufficient evidence has been provided that it does as with all medical practices. True enough, a claim of "homeopathy never works" is a claim for which evidence cannot be provided, but a claim of "homeopathy hasn't been demonstrated to work" is certainly a claim that one could back up with plenty of evidence.

Originally posted by jmercer
The thing that bugs me the most about when people who have chosen to leave something out of their worldview forget that it's a choice on their part, and argue about it as if it's a proven fact.

jmercer, I have always enjoyed your posts, and your comments on this thread are no exception. Thanks!

-Bri

[tsg]

Originally posted by Bri
Very interesting thread! Just wanted to add a couple thoughts...

I agree with tsg's statement, so would the "correct" statement be "X has not been proven to exist" or "You have not provided overwhelming evidence that X exists" or "You have not provided more evidence [or more compelling evidence] of the existance of X than the evidence against X" or something similar?

I've decided on "I have not seen anything that would lead me to believe X exists/works/is true", with, depending on the circumstances, an additional "and plenty to lead me to believe that it doesn't/shouldn't/isn't". The claim at this point is not that there isn't any evidence, only that I haven't seen it. You want me to believe? Show me.

[Bri]

Originally posted by tsg
I've decided on "I have not seen anything that would lead me to believe X exists/works/is true", with, depending on the circumstances, an additional "and plenty to lead me to believe that it doesn't/shouldn't/isn't". The claim at this point is not that there isn't any evidence, only that I haven't seen it. You want me to believe? Show me.

I thought about statements such as this, but they are clearly opinions ("that would lead me to believe") rather than actual statements of fact as implied in the OP (proving a negative). In addition, they are opinions concerning the validity of another person's claim rather than a claim in and of themselves.

Opinions don't require the same burden of proof than a claim of fact would, so I'm wondering if there's any actual statement of fact that one could make that isn't an agnostic one (i.e. "It is impossible to know..." or something similar). It seems that such a statement would be based on "evidence" rather than "proof" but even a claim of "overwhelming" or "compelling" evidence against something would require evidence to support that the evidence is overwhelming or compelling.

-Bri

[drkitten]

Originally posted by Bri

Opinions don't require the same burden of proof than a claim of fact would, so I'm wondering if there's any actual statement of fact that one could make that isn't an agnostic one (i.e. "It is impossible to know..." or something similar). It seems that such a statement would be based on "evidence" rather than "proof" but even a claim of "overwhelming" or "compelling" evidence against something would require evidence to support that the evidence is overwhelming or compelling.


If you want to get legalistic, simply point out that "the preponderance of the evidence says that" or "most evidence says" or something like that.

There are, for example, many more documented failures of remote viewing under controlled circumstances then there are documented successes. In fact, I know of no documented successes -- which suggests that the evidence is in fact, "overwhelming."

[jmercer]

Originally posted by tsg
I've decided on "I have not seen anything that would lead me to believe X exists/works/is true", with, depending on the circumstances, an additional "and plenty to lead me to believe that it doesn't/shouldn't/isn't". The claim at this point is not that there isn't any evidence, only that I haven't seen it. You want me to believe? Show me.

To me, that's a good skeptical declaration, possibly classical. :)

[tsg]

Originally posted by Bri
I thought about statements such as this, but they are clearly opinions ("that would lead me to believe") rather than actual statements of fact as implied in the OP (proving a negative). In addition, they are opinions concerning the validity of another person's claim rather than a claim in and of themselves.

On further reflection, I think a better choice of words would be "that would convince me" rather than "that would lead me to believe". It's purely a semantic distinction but has less connotation of faith.

[Francois Tremblay]

So how is it done?

It's called falsification. Look it up.

Anyone who thinks negatives are unproveable or shouldn't be proven, is simply against the scientific method - because the scientific method does not exist if there is no falsification. Simple enough !