Proof.

[nikolai_42]

Simple question. Is it possible to prove a negative?

In a bit more convoluted form, does it follow that because some statement is in 'negative' form that it is not provable? If not, what are the requirements by which it COULD be proved? What would be the first possible 'negative' thing provable?

 

[Jerry Smith]

Limited negatives are simple to demonstrate. For instance, if you were nearby, I could easily demonstrate to you that I am not holding an orange. Since oranges are visible to the naked eye, and since my holding capacity is localized to a small area, a brief search of that area will reveal the presence of an orange if I am holding it. Therefore, if you search me and find no orange, then you have ample evidence that I am not holding an orange.

Universal negatives are far more difficult to demonstrate. I could never demonstrate to you that no one anywhere was holding an orange. With enough time and energy, I could possibly demonstrate to you that no one on Earth was holding an orange (if indeed they were not). However, since there are areas of the universe (beyond the Hubble horizon) that cannot in principle be searched, I we could never search far enough to know that no one in one of those unsearchable areas was holding an orange.

Proof is impossible in natural investigations of any kind (limited or universal negatives and limited or universal positives). Proof belongs to the domain of mathematics.

 

[WinAce]

So you can't even be fairly certain that the invisible vacuum-breathing elephants somewhere beyond Pluto don't exist?!

 

[Orihalcon]

nooo, those elephants are my deities! don't try to prove their non-existance!

 

[Arikay]

But the question is, do you belong to the Pink elephant sect, or the grey elephant sect?

Today at 12:05 AM Orihalcon said this in Post #4 (http://www.christianforums.com/showthread.php?postid=656198#post656198)

nooo, those elephants are my deities! don't try to prove their non-existance!

 

[Jerry Smith]

So you can't even be fairly certain that the invisible vacuum-breathing elephants somewhere beyond Pluto don't exist?!

Not if we must rely only on empirical investigation. Reason has some other tools up its sleeve that might help us come to a conclusion of relative certainty regarding those elephants.

 

[nikolai_42]

Yesterday at 11:31 PM Jerry Smith said this in Post #2

Limited negatives are simple to demonstrate. For instance, if you were nearby, I could easily demonstrate to you that I am not holding an orange. Since oranges are visible to the naked eye, and since my holding capacity is localized to a small area, a brief search of that area will reveal the presence of an orange if I am holding it. Therefore, if you search me and find no orange, then you have ample evidence that I am not holding an orange.

Universal negatives are far more difficult to demonstrate. I could never demonstrate to you that no one anywhere was holding an orange. With enough time and energy, I could possibly demonstrate to you that no one on Earth was holding an orange (if indeed they were not). However, since there are areas of the universe (beyond the Hubble horizon) that cannot in principle be searched, I we could never search far enough to know that no one in one of those unsearchable areas was holding an orange.

Proof is impossible in natural investigations of any kind (limited or universal negatives and limited or universal positives). Proof belongs to the domain of mathematics.

I would think that some universal negatives would be easier to prove - in some circumstances. That is, given one instance where the negative doesn't hold (a double negative).

 Does that mean, then, that logic in general would be suspect IF there were a universal proposition that one could not prove a negative? Because then the fallacy would tend to disprove itself (i.e. if no negatives like that could be proven, the proposition could not be dismissed, and thus the proposition that no negatives could be proven would tend to dismiss itself...). Do I make any sense there?

 

[Jerry Smith]

Today at 08:44 AM nikolai_42 said this in Post #7

I would think that some universal negatives would be easier to prove - in some circumstances. That is, given one instance where the negative doesn't hold (a double negative).

If it is logically tied to a universal positive which can be falsified, then you will find it possible to prove a universal negative empirically. There is no deity that constantly changes the flavor of all oranges in the universe, so that they taste like grapes. This can be tested by tasting one orange from the universe. If it does not taste like a grape, then the deity in question does not exist..

Does that mean, then, that logic in general would be suspect IF there were a universal proposition that one could not prove a negative? Because then the fallacy would tend to disprove itself (i.e. if no negatives like that could be proven, the proposition could not be dismissed, and thus the proposition that no negatives could be proven would tend to dismiss itself...). Do I make any sense there?

The proposition that there is no universal negative which can be proven is self-referential and self-defeating. If the proposition could be proven, then it would be false. On this, you are correct.

The proposition that there is a class of universal negatives which cannot be empirically verified has been demonstrated on this thread. In my first reply, I gave an example of a universal negative which cannot be empirically verified. That statement is included in a class of universal negatives that cannot be empirically verified. What I have failed to do was shed light on how this class of universal negatives can be uniquely distinguished from the larger class of all universal negatives.

 

[lucaspa]

Today at 12:45 AM WinAce said this in Post #3

So you can't even be fairly certain that the invisible vacuum-breathing elephants somewhere beyond Pluto don't exist?!

If they are invisible, how do you know they are elephants?

WinAce, you can make any hypothesis/theory unfalsifiable if you wish.  Pierre Duhem showed this in 1905.  All you have to do is refuse to accept some of the underlying hypotheses.  You do that here by making elephants both invisible and able to survive without oxygen.  We both know that elephants are both visible and air-breathing. What you have done is reject both of those accepted underlying hypotheses to make your statement.

Now, if I simply refuse to reject them, and I should, your invisible, vacuum-breathing elephants are falsified.  Now, whether you will admit that is, of course, another matter.

In science, we remain agnostic toward all manner of hypothetical entities until we have the means to falsify them.  This drives militant atheists nuts because they desperately want to be able to declare deity not to exist without the ability to falsify it.  But it is the way it is.

 

[lucaspa]

Yesterday at 10:31 PM Jerry Smith said this in Post #2

Universal negatives are far more difficult to demonstrate. I could never demonstrate to you that no one anywhere was holding an orange. With enough time and energy, I could possibly demonstrate to you that no one on Earth was holding an orange (if indeed they were not). However, since there are areas of the universe (beyond the Hubble horizon) that cannot in principle be searched, I we could never search far enough to know that no one in one of those unsearchable areas was holding an orange.

Proof is impossible in natural investigations of any kind (limited or universal negatives and limited or universal positives). Proof belongs to the domain of mathematics.

I disagree, Jerry. I know, surprise.  A world-wide flood is a universal, yet that is falsified.  The aether was a universal, and that got falsified.

Universal negatives are "provable" by two means: 1) having deductions with observational consequences where you see observations that are the opposite of the deductions and 2) when you can search the entire search space.  You demonstrated the second in your post -- you would have to search all the people on earth at a given moment to prove that no one was holding an orange and still couldn't search beyond the visible horizon of the universe.  And there are no observational consequences that would be exhibited if someone were holding an orange.

But proof is possible. For instance, I would say it is proved that the earth is not flat, wouldn't you?

 

[Jerry Smith]

In science, we remain agnostic toward all manner of hypothetical entities until we have the means to falsify them.  This drives militant atheists nuts because they desperately want to be able to declare deity not to exist without the ability to falsify it.  But it is the way it is.

I don't know any militant atheists personally, nor have I encountered their feelings about science, but reasonable people need not be driven "nuts" by this fact.. Reason can reject many hypothetical entities outright without scientific (empirical) falsification. Reasonable people do not have to remain agnostic toward unfalsifiable formulations of Leprauchan hypotheses or Santa Claus hypotheses even though science is technically agnostic toward them. 

 

[Late_Cretaceous]

Can I prove that I have never been to Kansas City?
I can prove that I have been to London England, or Portland Oregon. But I cannot prove that I have NEVER been to Kansas City.

 

[Jerry Smith]

Today at 06:28 PM lucaspa said this in Post #10

I disagree, Jerry. I know, surprise.  A world-wide flood is a universal, yet that is falsified.  The aether was a universal, and that got falsified.

The world-wide flood was limited in scope (to the Earth). The aether should be considered universal, but cannot be demonstrated to be universally false. It has been falsified in the region of our solar system by the Michelson-Morley experiments. As a universal positive ("the Aether exists everywhere in the universe") it has been falsified. As a limited positive, ("the aether is required as a medium for electromagnetic raidation") it has been falsified. As a universal negative ("there is no aether anywhere") it is impossible to demonstrate. 

Universal negatives are "provable" by two means: 1) having deductions with observational consequences where you see observations that are the opposite of the deductions and 2) when you can search the entire search space.

1) that is, when it is tied to a universal positive,

2) If you can search the entire search space, it either a) does not apply to our universe with Hubble horizons, or b) is not truly universal.

You demonstrated the second in your post -- you would have to search all the people on earth at a given moment to prove that no one was holding an orange and still couldn't search beyond the visible horizon of the universe.  And there are no observational consequences that would be exhibited if someone were holding an orange.

But proof is possible. For instance, I would say it is proved that the earth is not flat, wouldn't you?

Yes, limited negatives are almost always demonstrable. The earth is demonstrably not flat. Proof lies only in the realm of mathematics. There is no proof in empirical science, only evidence that falsifies (does not conform to empirical observation), or evidence that confirms (accurately predicts empirical observation).

 

[WinAce]

If they are invisible, how do you know they are elephants?

Let's say they have the form of an elephant, which would be easily recognizable if they weren't invisible.

WinAce, you can make any hypothesis/theory unfalsifiable if you wish. Pierre Duhem showed this in 1905. All you have to do is refuse to accept some of the underlying hypotheses. You do that here by making elephants both invisible and able to survive without oxygen. We both know that elephants are both visible and air-breathing. What you have done is reject both of those accepted underlying hypotheses to make your statement.

Excuse me - how exactly do you know that all elephants are visible and air breathing? Have you seen every single elephant everywhere in the universe and other possible universes, which would be necessary to make that statement?

In science, we remain agnostic toward all manner of hypothetical entities until we have the means to falsify them. This drives militant atheists nuts because they desperately want to be able to declare deity not to exist without the ability to falsify it. But it is the way it is.

Technically, I can falsify one exactly as you've done my elephants. We both know that elephants are visible and air-breathing? Fine. We both know that mind requires physical brain, but gods supposedly don't have one. So, both invisible vacuum-breathing elephants and gods don't exist. I love compromise

Of course, if you say there's nothing preventing gods from existing without a brain, I can just say there's nothing preventing elephants from existing without breathing or being visible ... and we're back to square 1.

Then again, this thread wasn't really about gods or invisible elephants, so it seems I accidentally derailed it. My apologies.