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Offline Tom Bishop

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Re: Is it possible to prove a negative?
« Reply #200 on: January 04, 2014, 04:33:11 AM »
No, saying I don't know keeps me from making a fool of myself when there is insufficient data to come to a logical conclusion.

Sure there is. I have never seen evidence for ghosts, and the source claiming that they exist is unable to provide evidence of existence, so this is evidence that they do not exist.

I am not burdened to prove that ghosts do not exist.

Please tell me that I need to prove that ghosts do not exist if I disagree with someone who claims that ghosts exist, so we can all see how stupid you sound.
Then state it as abelief. I don't believe ghosts exist is much different that saying ghosts don't exist.

If someone shows you a picture of a ghost, that is their evidence.  You cannot then claim ghosts don't exist until you demonstrate that the picture is not genuine.  So please tell me you still don't understand the difference between a truth claim and a statement of belief.

Saying "I don't believe that" is also disagreeing with with the claimant. You are making an assertion that ghosts do not exist.

For example:

Person 1: The Ancient Egyptians have made successful limb transplants.
Person 2: I don't believe that. I don't agree that they would know how to do that.

Person 2 is asserting that the ancient Egyptians have not make successful limb transplants. In his disbelief, he is making the claim that it did not happen.
« Last Edit: January 04, 2014, 04:53:23 AM by Tom Bishop »

Rama Set

Re: Is it possible to prove a negative?
« Reply #201 on: January 04, 2014, 04:37:37 AM »
If we are talking about a formal debate, and someone has said ghosts exist, and has provided some evidence, then once you claim "Ghosts do not exist" you must either provide contradicting evidence or debunk the positive sides evidence.

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Offline markjo

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Re: Is it possible to prove a negative?
« Reply #202 on: January 04, 2014, 04:39:23 AM »
Saying "I don't believe that" is also disagreeing with with the claimant. You are making an assertion that ghosts do not exist.
Not necessarily.  Saying "I don't believe that" is not the same as saying "you are wrong".  It's saying that the claimant hasn't provided sufficient evidence to change the person's mind. 
Abandon hope all ye who press enter here.

Science is what happens when preconception meets verification.

Ignorance more frequently begets confidence than does knowledge. -- Charles Darwin

If you can't demonstrate it, then you shouldn't believe it.

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Offline Tom Bishop

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Re: Is it possible to prove a negative?
« Reply #203 on: January 04, 2014, 04:44:41 AM »
If we are talking about a formal debate, and someone has said ghosts exist, and has provided some evidence, then once you claim "Ghosts do not exist" you must either provide contradicting evidence or debunk the positive sides evidence.

Correct. The conversation proceeds once evidence is presented.

Saying "I don't believe that" is also disagreeing with with the claimant. You are making an assertion that ghosts do not exist.
Not necessarily.  Saying "I don't believe that" is not the same as saying "you are wrong".  It's saying that the claimant hasn't provided sufficient evidence to change the person's mind. 

If I say "water is wet" and you respond with "I don't believe that" then your statement is asserting that water is not wet. How could it not?
« Last Edit: January 04, 2014, 04:52:52 AM by Tom Bishop »

Offline bj1234

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Re: Is it possible to prove a negative?
« Reply #204 on: January 04, 2014, 05:07:46 AM »
Well, saying I don't believe water is wet is a good way to get evidence of how wet water can be.  I would splash the cup of water in their face.  The wetness of water is easily demonstrated.  In fact wetness is one of the properties of liquid water.


However, the existence of ghosts is not as easily proven or disproven.  So if one says I don't believe in ghosts, they are demonstraiting that they have come to a personal conclusion that ghosts do not exist.  They also are acknowledging that it is foolish to flat out deny the existence of ghosts because they have not fully examined ALL the exidence there is on ghosts.

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Offline markjo

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Re: Is it possible to prove a negative?
« Reply #205 on: January 04, 2014, 05:56:32 AM »
If I say "water is wet" and you respond with "I don't believe that" then your statement is asserting that water is not wet. How could it not?
No, I would be asserting that you have not provided enough evidence to support your claim that water is wet.  After all, what evidence did you provide that water is wet?  None.  You made a claim without providing any supporting evidence.  You also ignored the fact that water in its solid form (ice) is not wet.
Abandon hope all ye who press enter here.

Science is what happens when preconception meets verification.

Ignorance more frequently begets confidence than does knowledge. -- Charles Darwin

If you can't demonstrate it, then you shouldn't believe it.

Re: Is it possible to prove a negative?
« Reply #206 on: January 04, 2014, 05:18:01 PM »
There is a handkerchief in the pocket.    <--- a claim by which the claimant has the burden of proof.

There is not a handkerchief in the pocket   <--- a claim by which the claimant has the burden of proof. Not a skeptical statement. This is an assertion.

I don't know if there is a handkerchief in the pocket   <--- also a claim by which the claimant has the burden of proof but such a burden is easy to meet because the claimant is stating that they don't know if there is a handkerchief in the pocket. That itself, is the claim. There is no assertion in this phrase about whether the handkerchief is actually in the pocket, just the claim about not knowing, which the claimant is free to assert since the assertion proves itself. This is a skeptical statement.

A negative claim is an assertion.
« Last Edit: January 04, 2014, 05:19:59 PM by rottingroom »

Rama Set

Re: Is it possible to prove a negative?
« Reply #207 on: January 04, 2014, 05:46:49 PM »
I think the sticking point here is that Tom talks about situations where he negates a positive claim for which evidence has not been provided.  If someone makes a claim, provides evidence and then is met with a negative claim in rebuttal, obviously the person making the negative claim must support their position with evidence.

If someone introduces a negative claim, not as a rebuttal, but as a first statement, the person making this negative claim must provide evidence; you cannot force a burden of proof on someone who has not made any claim obviously.

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Offline Tom Bishop

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Re: Is it possible to prove a negative?
« Reply #208 on: January 05, 2014, 09:36:04 AM »
So, if someone introduces as a first claim, that there is no evidence that ghosts exist, it is their burden to prove that ghosts don't exist?

Offline bj1234

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Re: Is it possible to prove a negative?
« Reply #209 on: January 05, 2014, 10:58:17 AM »
So, if someone introduces as a first claim, that there is no evidence that ghosts exist, it is their burden to prove that ghosts don't exist?
Yes.  And they do this by showing reported evidence and explaining why this evidence is not genuine.  It is that simple.  They need to make atleast some effort more Than, well there is no evidence in my closet so therefore ghosts don't exist.  They need to do the leg work.


Rama Set

Re: Is it possible to prove a negative?
« Reply #210 on: January 05, 2014, 12:58:34 PM »
So, if someone introduces as a first claim, that there is no evidence that ghosts exist, it is their burden to prove that ghosts don't exist?

Of course. If you walk up to someone and say "Ghosts do not exist."  That someone is very justified in saying "How are you sure?"

A more practical example: you walk up to someone and say "Oranges are not good for your health." You must show some sort of evidence for this or there is no good reason to believe you.

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Offline Pete Svarrior

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Re: Is it possible to prove a negative?
« Reply #211 on: January 05, 2014, 04:24:14 PM »
Yes.  And they do this by showing reported evidence and explaining why this evidence is not genuine.  It is that simple.  They need to make atleast some effort more Than, well there is no evidence in my closet so therefore ghosts don't exist.
Isn't that what Tom does? The usual RE'er response to that approach is "Absence of evidence is not evidence of absence".
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Offline bj1234

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Re: Is it possible to prove a negative?
« Reply #212 on: January 05, 2014, 05:10:35 PM »
Yes.  And they do this by showing reported evidence and explaining why this evidence is not genuine.  It is that simple.  They need to make atleast some effort more Than, well there is no evidence in my closet so therefore ghosts don't exist.
Isn't that what Tom does? The usual RE'er response to that approach is "Absence of evidence is not evidence of absence".
No, He just claims it is not and walks away proclaiming he searched under his bed or some such statement.

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Offline markjo

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Re: Is it possible to prove a negative?
« Reply #213 on: January 05, 2014, 05:15:17 PM »
No.  Tom pretty much takes "I don't have to prove that I'm right but you have to prove that I'm wrong" approach and seems to think that the designers and builders of gravity satellites leave as little evidence of their existence as ghosts do.
« Last Edit: January 05, 2014, 05:16:55 PM by markjo »
Abandon hope all ye who press enter here.

Science is what happens when preconception meets verification.

Ignorance more frequently begets confidence than does knowledge. -- Charles Darwin

If you can't demonstrate it, then you shouldn't believe it.

Re: Is it possible to prove a negative?
« Reply #214 on: January 05, 2014, 06:31:54 PM »
tom: would you briefly explain what, in your opinion, is the difference between a 'negative' and 'positive' claim? what does that distinction mean to you?

Negative claims are an absence, not a reworded positive claim. It is not "0". It is "-".

I can't make sense of this.  What is an absence?  What is a positive claim and how is it different?

Negative claims hold a special distinction. If I claim that the window is NOT open, it does not mean I am claiming that the window is closed. I am claiming that the window is NOT open.

You say that it holds a special distinction, but you're not saying what the distinction is.  How do I recognize a negative claim when I see one?  Is it that it has the word 'not' in it? 

What if I claim that the window is not not open?  Is that a negative claim?  What about 'it is not the case that the window is not open'?  Is that a negative claim?

Also, what exactly do you think the word 'closed' means?



So, if someone introduces as a first claim, that there is no evidence that ghosts exist, it is their burden to prove that ghosts don't exist?

Yes.  Every truth claim has a burden of proof.  It sounds like you're saying that "Ghosts do not exist," and "I personally have encountered no evidence of ghosts," are logically equivalent statements.  They are not.
« Last Edit: January 05, 2014, 06:37:31 PM by garygreen »
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Offline Tom Bishop

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Re: Is it possible to prove a negative?
« Reply #215 on: January 12, 2014, 02:53:19 AM »
I see.

Person 1: Does the boogeyman exist?

Person 2: No...

Person 1: Ha! You just claimed that the boogeyman doesn't exist! Now you have to prove it!

Rama Set

Re: Is it possible to prove a negative?
« Reply #216 on: January 12, 2014, 04:32:01 AM »

I see.

Person  1: The Earth is not round.

Person 2: What?  Why would you say that?

Person 1: Prove me wrong!


Offline bj1234

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Re: Is it possible to prove a negative?
« Reply #217 on: January 12, 2014, 04:23:56 PM »
I see.

Person 1: Does the boogeyman exist?

Person 2: No...

Person 1: Ha! You just claimed that the boogeyman doesn't exist! Now you have to prove it!
Person 2: Here are some reported pictures of the boogey man.  This is why they are not genuine.  All pictures that have been reported of the boogeyman have been looked at and determined to be either faked or a case of mistaken identity.  Therefore, I conclude that there is not enough evidence to confirm the existence of a boogeyman.  Because these pictures are the most likely source of proof of the boogey man, I have concluded that the boogeyman does not exist.

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Offline Tom Bishop

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Re: Is it possible to prove a negative?
« Reply #218 on: January 12, 2014, 05:27:15 PM »
I see.

Person 1: Does the boogeyman exist?

Person 2: No...

Person 1: Ha! You just claimed that the boogeyman doesn't exist! Now you have to prove it!
Person 2: Here are some reported pictures of the boogey man.  This is why they are not genuine.  All pictures that have been reported of the boogeyman have been looked at and determined to be either faked or a case of mistaken identity.  Therefore, I conclude that there is not enough evidence to confirm the existence of a boogeyman.  Because these pictures are the most likely source of proof of the boogey man, I have concluded that the boogeyman does not exist.

That's an "absence of evidence is evidence of absence" argument. You said that there is little credible evidence that the boogeyman exists, and since there is no other evidence he therefore does not exist. We are told by the participants in this thread that absence of evidence arguments are invalid arguments. It still needs to proven that the boogeyman does not exist.
« Last Edit: January 12, 2014, 06:07:20 PM by Tom Bishop »

Rama Set

Re: Is it possible to prove a negative?
« Reply #219 on: January 12, 2014, 05:55:42 PM »
You were told that looking in your briefcase was not a sufficient search to declare an absence of evidence. I trust you can see why.