Proof of a negative

[m3talsmith_redu]

Some philosophy people claim you cannot prove a negative. Can anyone here prove that statement true? How about simply proving that a negative is really a negative and not a positive?

I mean someone had to prove it at first right? So how can this hold true if it needs proof first?

[tinybear]

Proof of a negative is more difficult, but by no means impossible.

[fedfem]

Quote by: tinybear Proof of a negative is more difficult, but by no means impossible.

Scientifically, a negative cannot be proven.

Even in criminal trials, the assertation that the defendent did not do something(a negative)cannot be proven unless--in the case of an alibi--he can prove he was somewhere else. I mean a positive assertation needs to be proven rather than the negative one.

In religious claims--the assertations of proof can be disproved by showing an alternate explanation for a claim. For example, some believe the Virgin Mary's image is on an underpass. By pissing on a concrete wall, a similar image can be produced showing the alternate explanation.

[JamesMcBride]

Can one prove a negative by proving the positive to be false?

[Starboy]

Quote by: JamesMcBride Can one prove a negative by proving the positive to be false?

Only if you know what you are looking for. There are many cons that pretend to know and then when they find something even remotely close they say, "That's it!".

Starboy

[RickSp]

Quote by: JamesMcBride Can one prove a negative by proving the positive to be false?

Proving a positive to be false does not preclude all other alternatives that could be true.

The idea of "proving a negative" usually becomes rhetorical nonsense pretty quickly. Here is an essay by Richard Carrier on the logical issues involved in Proving a Negative .

Negative statements often make claims that are hard to prove because they make predictions about things we are in practice unable to observe in a finite time. For instance, "there are no big green Martians" means "there are no big green Martians in this or any universe," and unlike your bathtub, it is not possible to look in every corner of every universe, thus we cannot completely test this proposition--we can just look around within the limits of our ability and our desire to expend time and resources on looking, and prove that, where we have looked so far, and within the limits of our knowing anything at all, there are no big green Martians. In such a case we have proved a negative, just not the negative of the sweeping proposition in question.

[tman_ndsu08]

You can't prove a negative statement to be true unless you can observe every observable position in the universe simultaneously (impossible).

For example: "god doesn't exist".

I can't see him, so he doesn't exist, right? Well, maybe he exists over there behind that wall where you can't see him! Ok, I put a camera behind the wall and he's still not there. Well, maybe he's over there behind that other wall. Another camera, no god. Well, actually, he's in outer space hinding behind an asteroid. Ok, another camera, no god. Well....forever and forever until ever possible position in the universe has a camera looking at it and you can't detect god. But you can always come up with another place that he could be, and since you can observe all places at once, you can't prove that he isn't at the place you couldn't observe.

[tinybear]

Say you're charged with selling goods in a public place without a valid licence. All the prosecution needs to prove is you were offering goods for sale in a place where the public has access and that when asked to produce a licence you did not do so. They don't need to go further to prove that you did not apply for a licence or that you applied for one but was refused or that you had a valid licence but it had expired on the day in question. In other words, the prosecution need not prove a negative, i.e. that you did not possess a valid licence. But is it in fact possible for them to prove it? I would say yes.

[fedfem]

Quote by: tinybear Say you're charged with selling goods in a public place without a valid licence. All the prosecution needs to prove is you were offering goods for sale in a place where the public has access and that when asked to produce a licence you did not do so. They don't need to go further to prove that you did not apply for a licence or that you applied for one but was refused or that you had a valid licence but it had expired on the day in question. In other words, the prosecution need not prove a negative, i.e. that you did not possess a valid licence. But is it in fact possible for them to prove it? I would say yes.

In your example the prosecutor has to prove the crime.




edited typo

[tinybear]

Of course it is the general rule that the prosecutor has to prove every ingredient of the offense. But where one of the ingredients is a 'negative' , e.g. that the defendant does not have a valid licence, the law makes an exception. the prosecution need only prove the facts which leads one to infer the existence of the negative instead of requiring positive proof the said negative.

[kingjust]

Quote by: m3talsmith_redu Some philosophy people claim you cannot prove a negative. Can anyone here prove that statement true? How about simply proving that a negative is really a negative and not a positive? I mean someone had to prove it at first right? So how can this hold true if it needs proof first?

Yes you can prove a negative. But there are prerequisite to make it so. Like what is the negative deriving from. Can we all agree that the positive is the first setiment to come from any person. Actually if we can change the negative to not believing the assertion and the positive being the original assertion. With that being said: A car accident happens, and the person who got hit comes out of the car stating it is the other persons fault (assertion or the positive). And the person who was blamed denies it and nows has to prove it (the negative or not believing the assertion. Now what the blamer doesn't know that it was all caught on tape, and when in court the tape shows the blamer and not the blame'ee was at fault, answering the blame'ees negative.

Kind of a lame example and convenient, sorry. Hopefully it makes sense with the comment I stated that there are prerequisite in proving the negative (denying the asserition and having to prove it) in response to the positive (original assertion).

[kingjust]

Quote by: m3talsmith_redu How about simply proving that a negative is really a negative and not a positive?

I just realized something, there is a chain of custody per se' in the proving the negative and your comment. Once you have proven your negative, it becomes a positive when someone who disagree's with your negative has to prove his/hers negative. Completely starting a whole new "chain", which will more than likely end up coming back to the beginning arguement making it the dreaded cirucular arguement scenario. How ironic. Trying to avoid the circular argument, just ends up creating one! Interesting!!! Indeed!