The "you cannot prove a negative" argument

That's pretty senseless and self-servingly smug (using your own term) right on the face of it.

Here's a challenge for you: Prove that Bigfoot does not exist.

 

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Or Santa Claus. Or Zeus. But you can always play the Lightgigantic game and say that just because you can't see Santa's workshop at the north pole doesn't mean it doesn't exist - you simply aren't in the right frame of mind to perceive it.

When "other ways of knowing" actually provide something worth knowing, I'll pay attention.

 

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In what ways would you investigate the claims "bigfoot does not exist" and "bigfoot exists" differently?

 

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So lets disambiguate the claim "you cannot prove a negative":

Disambiguation A: There is no negative such that you can prove it.

Disambiguation B: There exists a negative such that you cannot prove it.

A is, of course, what people mean when they say "You cannot prove a negative". B is trivially true and uninteresting. So asking me to prove that bigfoot/santa/zeus/whatever doesn't exist does nothing to prove your point. Just because there are some negatives that you cannot prove, does not imply that no negatives can be proven.

Here's a few negatives that can be proven. I'll post them in premise/conclusion argument forms, and I challenge you to show me how my proofs do not work without resorting to standard skeptical arguments/reasoning that would, if applied, invalidate any form of a posteriori knowledge. Because if the whole "can't prove a negative" slogan is to be interesting or meaningful it has to be something other than standard skeptical posturings.

Argument 1:

1) Barack Obama is married.
2) If 1), then Barack Obama is not a bachelor.
So, 3) Barack Obama is not a Bachelor.

We've proven a negative! Namely, that Barack Obama is not a bachelor. You can see how any number of arguments of this form can be drawn up, taking advantage of the simple fact that so many things can be defined in terms of the negation of other things. In this example, being married entails not being a bachelor.


So maybe the holder of the "can't prove a negative" position is thinking that the slogan only applies to negative existential statements. Well there's no dice there, either:

Argument 2:

1) There exists an x such that x is Barack Obama and x is married.
2) For any x, if x is married then x is not a bachelor.
3) So (subconclusion), there exists an x such that x is Barack Obama, and x is not a bachelor.
So 4), There exists an x such that x is not a bachelor.


Clearly, proving a negative holds up just fine under existential quantification.

I'll restate my point: the "you can't prove a negative" slogan seems vacuous to me, and I don't see how it is anything more than standard skeptical posturings. Those same posturings, of course, rule out any form of a posteriori knowledge under the slogan-holders ludicrously strict standard of proof, yet most of the slogan-holders do not seem to realize this fact.

 

I should say something about the standard situation in which this claim appears, namely in the following dialogue between Atheist and Theist:

A: Prove God exists.
T: Prove God doesn't exist!
A: You can't prove a negative.

Now I think what Atheist ought to do in this situation is say "ok, but first tell me the falsification criteria for the thesis that God exists so that I know what I have to prove to prove that God doesn't exist". That is where Theist's argument generally falls apart. Alternatively, the Atheist could argue that the epistemic default with respect to the existence of anything is that it doesn't exist unless proven otherwise. But I think the first strategy is more fun.

 

Alas, this has been pointed out numerous times to those who think that the lack of disproof entails proof.
For those of any intellectual persuasion whatsoever, it should be understood that the burden of proof always lies with the advocate of the irregular.

Technically, the question that this thread asks has been answered a number of times. If anyone feels that they would like to entertain some of the issues that have been brought up herein, that go beyond the logical and semantic scope of this question in particular, please feel free to start a new thread.

 

That's fine; I've never stated that there are no negatives that can be proven in this thread. I'm not quite sure if I've ever stated "You can't prove a negative", but if I have, it has been in response to "Prove (there is no god, that astrology doesn't work, that humans have not been abducted by aliens, NASA really sent a spacecraft to the moon....). Nothing in this thread has changed my position about the burden of proof about such things.

 

There is a problem with the above. See if you can see it.

The epistemic default of a general consensus including experiencers and non-experiencers alike.....

that beginning works.

But for each of us as individuals to take that on as a rule without that clarification would be ridiculous. There are many things we cannot prove that exist or have existed before they could be proven to the general public or the scientific community. Even using probablistic versions of 'prove.'

Otherwise every person encountering something new or outside mainstream acceptance is actually hallucinating UNTIL proof can be provided. That they themselves should assume this to be the case.

To put this all another way: it hinges the existence of entities on proof.

If you personalize this, you can also see how limiting it is. If I experience something, repeatedly, that I cannot prove exists to others, it may be quite rational for me to move forward on the assumption that it is real. Skimming back through history or the history of science one can find many examples where it would have been irrational for experiencers to use the epistemic default suggested in your quote. For others, whom they may have reported to, the default works, at least for the group as a whole. On the other hand, even there, if certain members of the group have developed great respect for the individual a more agnostic stance seems more rational to me.

 

The burden of proof depends on who is making the assertion. If a theist asserts there is a God, he gets the burden. If the atheist asserts there is no God, she gets the burden.

If you dont think the latter is true, consider how the agnostic would view the burden of proof in both situations.

 

Not to get in the middle of things here, so to speak, but...

I couldn't disagree more.
The one who holds a position is entirely irrelevant to any evidenciary requirements of the assertion [or denial] of the position. A thermostat for example, holds a position; how could the burden of proof lie with it?
Evidenciary requirements are always, necessarily, a function of the content of the assertion itself.

 

It is in the post.

 

This implies the burden or proof exists with science to create the original material of BB.

It cannot just emerge.

So, where is it?

If science has no proof, then it rests on faith.

 

No, it does not.

BBT does not theorize about events leading up to the Big Bang or to the creation.

BBT covers only what happened AFTER creation. It does not address creation.

 

Am I in the right place? I mean, this thread seems so logical and everything...

I would like to mention "standard of proof", if I may. For example, every negative (including Barak Obama being a bachelor) rests on faith, to some degree. Were you at his wedding? Have you seen the marriage certificate?

Well, of course not, but everybody, or more specifically, people whose job it is to know such things, say it is true that he is married.

One could say the same about affirmative claims, and they would be right, in general, or in a vacuum. The difference in "scientific" truth lies in reproducibility. However, until I personally build a LHC to look for sub-atomic particles, I must assume that those who have access to such equipment report truthfully on the results of their experiments.

And this is when I'm using the "I saw it with my own eyes" standard. So to a degree, we all go about our lives believing things based on faith, both positive and negative.

It depends on what the "standard" of proof is.

 

Finally - the voice of reason!!

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I lost interest in this thread ever since I saw some people sliding off into the metaphysical world and ignoring simple logic. And things like the *very* stupid, stupid statement that said (to slightly paraphrase), "everything should be considered equally true unless proven false." And there was even a qualifier on the end of that!! WOW!

There are MANY scientific things that have stood the test of time - and are perfectly suitable to rule out many absurdities that are often proffered as fact. A good example of the latter is the speed of light in a vacuum varies and another is the existence of psi abilities.

Nor is it necessary to prove that a mixture of chlorine and hydrogen, when ignited, does NOT produce ordinary water.

 

Well, geeez,...

I am so glad someone whom other people listen to pointed out a falasy, here. Let's ignore:

You know what? ... off, all of you...

 

If it's any consolation, this total nube read and agreed with your post that referred to the difference between "faith" and "acceptance of clear evidence that supports logical conclusions."

It's a funny thing, posting on a net forum.
Because you never know how readers are going to react.
You might crack a joke- and you have no idea if they laugh their butts off, consider you crude, roll their eyes- Whatever- unless they specifically post after you to tell you so.

People are MUCH more inclined to post after you if they disagree with you than if they agree. Posts declaring agreement make threads pop up as new Info and to have that happen often for just an "I AGREE!" could wear thin. So most folks don't.

If you're feeling ignored- it probably means people are agreeing with you. When people pay a lot of attention to you is when you gotta worry.

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I'm kinda one of those people that can drive a person nuts.
I'll have you laughing one moment and frothing with rage the next.
You'll hate my guts and then wanna hug me.

So I've definitely been on the receiving end of plenty of folks opinion about me, some rather unwanted assumptions about my personal character, horrifying rumors, very flattering compliments and a few idle death threats.
Can't let it get ya down-- Post strong, stand strong.

 

I can NOT prove a negative argument.



...
There, just did it.

 

Hi Read,

Cognitively, I agree. I just have some trouble reconciling it in terms of ontology and belief. The condition of suspended belief seems to me to lay solely in the area of epistemology. Regarding a belief for which one does not feel there is sufficient evidence to draw a decisive conclusion one still has to come down either on the ontologically positive or negative side when it comes to the point of making a decision. For example, you may believe the noise you heard may or may not be an oncoming train but you either get off the tracks or you don't. It's not that I don't believe there such a thing as a logically agnostic position, I just find it inconsistent in terms of pragmatism.

I guess I need to be more explicit. In an absolute or purely logical sense I agree. All assertions, indeed all “knowledge”, are tentative in this sense. While this should be understood I don't find it necessary (indeed I find it problematic) to attach it to everything.

In terms of reasoned belief, I find it untenable. Mind you I'm not asserting that one should draw a conclusion from no data at all but from an observable lack of evidence after a reasonable investigation. For example; if someone asserts there is an elephant in the room and you walk around and look throughout the room and find no elephants it is reasonable to conclude the assertion is false. To insist that one should remain undecided is unwarranted.

Anticipating some objections, I'll also state that what constitutes a reasonable investigation depends upon what the claim is. An elephant in the room does not require much investigation. The assertion that prayer affects health requires a bit more. This is in agreement with the Rule of Laplace that Fraggle just mentioned in that the scope of the claim sets boundaries of the argument. Untestable claims remain philosophical curiosities, interesting from a logical perspective but outside the bounds of reasonable assertion.

Regarding the example of your friend I find that the Doctors made an error in logic not with the conclusion that upon finding no evidence of illness she did not have one but in the leap to the conclusion, without evidence of such, that her problem was necessarily psychological. As you stated they should have approached that conclusion tentatively. Not finding evidence of such would then have returned them to investigate the possibility of physical illness further.

No, I don't make these assumptions. But I have every right to challenge their assertions just as they have right to challenge mine.

I do understand your objection, I just feel it applies to the realm of logic and not pragmatic, reasoned belief. As it applies to the latter it would be incapacitating.

~Raithere