How Do You Prove Something Doesn't Exist?

[BottleOfAwesome]

"The absence of evidence is not the evidence of absence"

http://www.youtube.com/watch?v=_w5JqQLqqTc

 

[MrStab]

It's possible for some things but not all and the only example I can think of at the moment was when Michelson and Morley proved that there was no such thing as the Aether, which was supposedly a medium used to carry light.

 

[Brandon237]

The absence of evidence is not the evidence of absence. Basically, you can't prove something isn't there, just because there is no evidence, which means you can't disprove something, EVER.

That depends, you can disprove an idea about the workings of the universe through observation and experimentation, but I agree that to disprove a physical entity is... not really possible.

 

[Frenger]

Saw that Bertrand Russel was already mentioned, but I'll leave this here anyway:

http://en.wikipedia.org/wiki/Russell%27s_teapot

 

[Richardplex]

Technically if the Universe if infinite then everything that can exist must exist somewhere = P

That does not follow at all.

For example there are an infinite number of odd numbers, but none of them end in 2, no matter how high you count.

It does follow, you missed the key words "everything that CAN exist", odd numbers have a probability of 0 of ending in a 2, thus cannot exist. If there is a probability it does exist, then not only will it exist, there will be an infinite number of them, in an infinite universe.

OT: I'll be that guy then. You can't prove anything exists, beyond that you yourself exist in some form, therefore, if you can't prove something exists, how can you prove something does not exist? The only place you can prove something does or does not exist is in pure mathematics, because mathematics is not flawed by reality.

Also, to continue being that philosopher guy, one needs to fully define what it means to exist. For example, in the OP example, the 2 people probably have a source from which the trader had inspiration to create the 2 characters (not played Fable, so this probably isn't making much sense, bear with me). So, in some way, the characters exist, not all their information in one place, but spread out throughout the different sources the trader conjured them from.

/end being philosophical

 

[disfunkybob]

The absence of evidence is not the evidence of absence. Basically, you can't prove something isn't there, just because there is no evidence, which means you can't disprove something, EVER.

That depends, you can disprove an idea about the workings of the universe through observation and experimentation, but I agree that to disprove a physical entity is... not really possible.

What are we, and all physical entities, but the working concepts of the universe. But I digress.

We should make sure to keep a division/scale between things you can prove exist and things you can't prove don't exist. Like so (based on current understanding):

(hey look, I have a hand)-------------(wormholes)--------------(flying spaghetti monster)

Giving "flying spaghetti monster" the same empirical or existential weight as "hey look, I have a hand" is illogical and will breed superstition.

 

[Srs bzns]

This way:


1. ... "What doesn't exist?"
2. Continue being oblivious about said objects' existence.

 

[Murray Whitwell]

Essentially:
http://en.wikipedia.org/wiki/Russell's_teapot
But people who make these ludicrous claims are the ones who bury their heads in the sand when it comes to having any sensible responsibility to their claims. They don't care for burden of truth

 

[Blackdoom]

Google it, if you get no results it doesn't exist.

 

[Halceon]

You demonstrate that whatever is necessarily caused by the existence of said object or phenomenon doesn't occur or that the circumstances necessary for the object or phenomenon's existence are impossible/currently not true.

This is possible for some things, like phlogiston, prayer groups and aether, but not for others, like pink elephants with teapots orbiting a planet in a galaxy beyond our light cone. However, things that can't be disproved are usually things that can't be proven and are to be considered hypothetical at best. Problem is - people get very attached to their explanations to things, considering only whether they can be disproved and almost never considering whether it can be proved or even if there's any reason at all to believe it.

 

[Kiefer13]

Technicially you can't, but you shouldn't have to.

The burden of proof is on the person attempting to assert something, not the person attempting to dismiss it. As has been mentioned, see Russell's Teapot [http://en.wikipedia.org/wiki/Russell%27s_teapot].

 

[viranimus]

You can't, quite simply. But in a situation where this kind of thing arises, the onus of proof is on whoever claims that the thing does exist.

That is almost correct. The burden of proof falls to whatever claim is being made, not who ever made the claim that it does exist as a default Because if something was always accepted as a given and then you come along and say it does not exist, it is you who are making the claim in that your claiming it does not exist. If you make the claim the burden of proof falls to you. If your making a claim you do not get the luxury to hide behind your inability to back your claim up.

Edit: Teapot be damned, and Bertrand was a hack.

 

[Realitycrash]

The absence of evidence is not the evidence of absence. Basically, you can't prove something isn't there, just because there is no evidence, which means you can't disprove something, EVER.

Unless you put up these fancy groundrules called "Axioms" which is pretty much something saying "Okey, you can argue any point and anything that is even remotely connected with reality, except this"

 

[brendonnelly]

Technically if the Universe if infinite then everything that can exist must exist somewhere = P

That does not follow at all.

For example there are an infinite number of odd numbers, but none of them end in 2, no matter how high you count.

Also the universe is not infinite, conservation of mass/energy
Edit: To weigh in, the onus of proof should fall to those trying to prove existence, not those trying to prove a lack thereof.

 

[baconsarnie]

With maths.
Or just shout and use incorrect (but not immediately noticeably wrong) logic.

 

[b3nn3tt]

You can't, quite simply. But in a situation where this kind of thing arises, the onus of proof is on whoever claims that the thing does exist.

That is almost correct. The burden of proof falls to whatever claim is being made, not who ever made the claim that it does exist as a default Because if something was always accepted as a given and then you come along and say it does not exist, it is you who are making the claim in that your claiming it does not exist. If you make the claim the burden of proof falls to you. If your making a claim you do not get the luxury to hide behind your inability to back your claim up.

Edit: Teapot be damned, and Bertrand was a hack.

But if something is already accepted, then it's reasonably safe to assume that there is some evidence for its existence. In which case the person coming in saying it doesn't exist can be argued against quite easily.

Or, alternatively, the person claiming something doesn't exist could point out flaws in the evidence for its existence. But in this case, they still can't bring in ny evidence of their own, because there can never be evidence that something doesn't exist.

 

[Hagi]

Assume it in fact does exist.
Logically derive what would happen.

If it leads to impossibilities then you've proven that it does not exist.

You've got event A which you wish to argue does not exist.
You assume event A does in fact exist. Logically event A would cause event B to happen.
Yet in reality event B does not occur, as such event A does not exist.
Or maybe event A would prevent event B from happening yet in reality event B does occur.
Again you've proven that event A does not exist.

Or in formal language:
A -> B
~B
-------
~A

or

A -> ~B
B
-------
~A

Or in Wikipedia:
http://en.wikipedia.org/wiki/Modus_tollens

 

[Kitteh]

simple crusade logic: kill all the heathen believers!

 

[Father of Worlds]

To prove that something does not exist, you must either prove that its existence would necessarily have effects that are not observed (if there's a man-eating dragon in my garage with no self control, then going into the garage would result in getting eaten. I can go in without getting eaten. Therefore, there isn't a man-eating dragon with no self control in my garage) or prove that it's logically incoherent (there are not, anywhere in the universe, any 3-sided cubes). The former depends on extreme specifics (I didn't prove that there are no man-eating dragons with no self control, just that there aren't any of those in one specific place). The latter depends on very broad categorizations (all cubes have 6 sides, everywhere, all the time). Otherwise, the best you can get is "there's absolutely no reason to think that X is real, therefore I'll assume it isn't for the moment."

In the OP case of Avo and Skorm being fictionalized, even if you could prove that there was in fact a trader who'd invented them, all that would prove was that the idea of them entered in to the popular consciousness through someone saying something he believed to be false. That doesn't prove that Avo and Skorm aren't also, quite independent of anyone's belief about them, real. If I could prove with absolute certainty that the bible was entirely fictionalized, that nobody represented in it existed, that nothing depicted in it happened, and that everyone who wrote the stories down knew that they were lying, that would not prove that god didn't exist. Just that the events and stories depicted in the bible are not accurate reflections of reality.

 

[Kathinka]

reminds me of this one comic..where is it..ah yes^^

in all seriousnes though: yes you can prove the nonexistence of something by evidence. how hard this evidence is to find might be another story.