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Post by jean on Mar 1, 2011 10:46:55 GMT 1
...the word 'proof' is not a good word to use. It should be about what evidence, or lack thereof, exists in support of some idea. Of coourse, abacus. That is why I said in my #8: It involves the presentation of evidence, to begin with. (He may be on form, nay, but it's not very good form, is it?)
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Post by abacus9900 on Mar 1, 2011 10:49:57 GMT 1
...the word 'proof' is not a good word to use. It should be about what evidence, or lack thereof, exists in support of some idea. Of coourse, abacus. That is why I said in my #8: It involves the presentation of evidence, to begin with. (He may be on form, nay, but it's not very good form, is it?) Oh dear, and I thought we were improving you. Don't be like STA, simplex, that is one example not to follow.
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Post by jean on Mar 1, 2011 11:12:49 GMT 1
Never mind the good advice, abacus.
I'm still waiting for anything resembling evidence for the claim you made in answer to nay's OP.
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Post by abacus9900 on Mar 1, 2011 13:17:57 GMT 1
Never mind the good advice, abacus. I'm still waiting for anything resembling evidence for the claim you made in answer to nay's OP. Well, just look at what James Randi does. He offers $1,000,000 to anyone who can substantiate any paranormal claim under laboratory condition. Needless to say he hasn't had to part with any money yet. 'Nough said?
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Post by jean on Mar 1, 2011 13:43:51 GMT 1
Not really.
Absence of proof, you see, is not the same as proof of absence.
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Post by abacus9900 on Mar 4, 2011 11:44:05 GMT 1
Not really. Absence of proof, you see, is not the same as proof of absence.Well, you could go on like that forever, always maintaining something may be true despite there never being any evidence for it.
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Post by petergriffin on Mar 4, 2011 14:02:01 GMT 1
I can prove a negative.
I am not dead - proof, I am alive enough to type this message. Lets not get into a big debate on defiantions of live and dead here, especiallly regarding my brain.
I am not overdrawn at the bank - proof I've got money in back account (its early in the month)
Both of which are true at the point to typing this.
Oh Hum Enough fun
I assume the key issue is, can you prove a scientific negative? If so I supose the top contender for this must be Godels incompleteness. and I think a fields medal lies in wait for someone who can solve that.
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Post by jean on Mar 4, 2011 14:56:10 GMT 1
I can prove a negative. I am not dead - proof, I am alive... There, you're not proving a negative so much as proving the related positive, a much easier thing to do. In any real-word example that I can think of, that's always the case. The more difficult it is to come by conclusive evidence of the related positive, the harder it is. Abacus says he can prove there's no life after death, but he has not done so. (I don't know if scientific negatives are different. I leave them to the scientists.)
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Post by abacus9900 on Mar 4, 2011 16:53:39 GMT 1
I can prove a negative. I am not dead - proof, I am alive... There, you're not proving a negative so much as proving the related positive, a much easier thing to do. In any real-word example that I can think of, that's always the case. The more difficult it is to come by conclusive evidence of the related positive, the harder it is. Abacus says he can prove there's no life after death, but he has not done so. (I don't know if scientific negatives are different. I leave them to the scientists.) Aren't you pushing this so far that it is becoming meaningless?
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Post by jean on Mar 4, 2011 17:24:09 GMT 1
No.
I'm not pushing anything at all - just pointing out that nay asked a question, and nobody's answered it.
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Post by robinpike on Mar 4, 2011 18:15:33 GMT 1
Isn't an example of a negative statement something like: "There are no little green men on mars."
Which is impossible to prove, but it can be disproved.
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Post by marchesarosa on Mar 4, 2011 19:05:54 GMT 1
The difficulty of proving a negative refers to a general statement not a specific one. It should be easy to prove or disprove a specific statement about a specific phenomenon. It is just a matter of asking “is it the case that such and such blah blah blah ...?”
General statements are always open to the possibility that some counter example of the proposed generalisation will exist some day, some time, somewhere.
“There is no afterlife” cannot be proved but neither can it be disproved since we do not have absolute knowledge. It is like the existence of God. We can have a pretty good idea of the answer to “is it the case that God exists?” but not 100% certainty, so we cannot speak of “proof”.
I think “proof” implies certainty.
However, most of the time "reasonably sure" is good enough to get by on.
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Post by abacus9900 on Mar 4, 2011 22:01:17 GMT 1
The difficulty of proving a negative refers to a general statement not a specific one. It should be easy to prove or disprove a specific statement about a specific phenomenon. It is just a matter of asking “is it the case that such and such blah blah blah ...?” General statements are always open to the possibility that some counter example of the proposed generalisation will exist some day, some time, somewhere. “There is no afterlife” cannot be proved but neither can it be disproved since we do not have absolute knowledge. It is like the existence of God. We can have a pretty good idea of the answer to “is it the case that God exists?” but not 100% certainty, so we cannot speak of “proof”. I think “proof” implies certainty. However, most of the time "reasonably sure" is good enough to get by on. Well, quite, so it's rather more of a game asking it than it really being a soluble question.
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Post by petergriffin on Mar 7, 2011 17:25:31 GMT 1
The only thing I can think of where a theroy is based on a negative is Fermat's last therom, which I think states the xn + yn <> zn where n <> 2 (I wish I could figure out how to get superscripts into the post) which is a negative, but it may be the way it is stated. I think it was more xn+yn=zn only where n=2. But the fact that it has been proved for all values of n then you could strech a point to say x3+y3 does not equal z3.
But thats now getting into symantics.
As for little green men on mars, how do you know there are none. Just because there is no evidence (yet) doesn't mean they dont exist.
I think this thread is proving a very good point, its much more difficult to prove a negative than you would think at first.
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Post by speakertoanimals on Mar 7, 2011 19:34:01 GMT 1
Except Godel himself proved that, so not a great example.................
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