You can't prove a negative

[Denny Crane!]

I have posted my own piece of writing on this board as well as arguing it numerous times in various threads but this article does it more logically and eloquently than I have:

“You can’t prove a negative.”


People who are searching for excuses to believe silly things frequently make this statement. A theist makes a positive assertion, and then declines to provide a basis for it. You deny their assertion (rightly so, what with no basis and all), but your denial is deemed invalid because it is impossible to prove a denial.

There is so very much wrong with this situation, it will take a while to wade through it.

The rules of logic and science indicate that there must be some kind of basis (either in substance or in thought) for an assertion or else it must be denied. An assertion, without evidence, is not accepted as true. That is the default position, the position that defines what critical thought is. Critical thought means not believing things you are told unless there is evidence to back it up. And without critical thought, logic and science are abandoned, and this is the only kind of productive thought humanity has ever come up with. To reject critical thought is to turn one’s back on thinking and embrace the Dark Ages. That’s the answer to this statement in theory.

However, in practice, there is usually a lot more happening with the person who makes such a proclamation. The person who makes this kind of statement has a great many fundamental misunderstandings about the nature of logic, science, and productive thought.

First, many people who believe in God do not realize that in every discussion about theism, their assertion is implicit: God exists. They do not need to say it. Every argument they make is under the assumption that the statement “God exists” is true. The fact that they identify themselves as believers is enough to serve as an assertion that a deity or deities exists. No assertion is being made by an atheist (at least not a smart atheist). The word “god” hasn’t even been defined and the nature of belief in that god has not been described; these must take place before any substantial discussion about the nature of God can begin. Atheists have no reason to provide these descriptions – without any beliefs about God, they have no reason to do so. It must be presumed that this onus rests upon the theist. The mere mention of one’s belief in God serves as an assertion that God exists.

Secondly, a person who rejects an assertion does not need to provide any justification for it. The evidence has to be provided by the party making the assertion. The person rejecting the assertion needs to provide nothing at all. Many theists try to escape this basic fact of life by declaring (in opposition to common sense) that their assertions need to be justified only to themselves in their personal experience. Simply put, that what is true for others might not be true for themselves. But this is madness – this also turns its back on productive thinking. This idea is called “solipsism,” and it refers to the notion that every person lives in his own reality, and what is true in his or her life might not be true for others. This is an old idea and it was shown to be ridiculous many centuries ago. Think about it – if it solipsism really was real, there wouldn’t be any books, schools, learning, or science. And people would never be able to communicate effectively.

Thirdly, the statement that “you cannot prove a negative” is simply false. On the surface, it seems to be true: if Person A says “I think God exists” and Person B says “I don’t think God exists,” it’s pretty clear that Person B is going to have a hard time proving that there isn’t a God. However, if you look a little closer, it actually depends on the nature of the negative statement being made. Here are some negative statements that can be proven very easily:

Five is not equal to four
The ancient Egyptians did not watch Seinfeld
The tsetse fly is not native to North America

Clearly, it’s possible to prove a negative statement. The real problem here is clearly the nature of the positive statement being refuted. When a person asserts that God exists, he does not specify the nature of God – that is, is God small, large, blue, red? And where is he? Of course it is not possible to prove that God does not exist, if “God” is a thing that has no definition, no characteristics, and no location. In fact, you can prove just about any kind of negative you can think of – except for (surprise!) the non-existence of mystical beings. When you get right down to it, the statement “you cannot prove a negative” is really just a different way of saying “You can’t prove me wrong because I don’t even know what I’m talking about.”

Logical statements have to abide by certain rules and restrictions. In order for a statement to be logical, it must be falsifiable, which means that it has to be presented in such a way that it could be proven incorrect. A statement is not logical if it cannot be tested to make sure it is true. The existence of God is not a logical question at all, and is therefore nonsensical. Of course you can’t prove that God doesn’t exist – no one even knows what God is supposed to be.

http://www.graveyardofthegods.net/ar...enegative.html

[Blau&Gruen]

Good article.

I find especially the defer interesting:

“you cannot prove a negative” is really just a different way of saying “You can’t prove me wrong because I don’t even know what I’m talking about.”

Two points maybe:
- the use here of 'logical' appears a bit close to the colloquial use
- besides the implicit affirmative assertion, there is also a dialectic use of these terms

[Biggreenfellow]

I'm not sure I agree for 100%; sure, there are a lot of negatives that can be proven, but as the article itself stated, the non-existence of God is not among those. The author really is just saying 'you can't prove a negative' in a different way; it can't be proven, because it's not a logical question.

[Blau&Gruen]

If you relate the opening post of this thread with some others elsewhere, you note that not all is lost.

[Vizsla]

You can never logically defeat the arguments of someone who insists in believing that something that cannot be proved is true. There will always be another tree for Big Foot to hide behind or another mountain for Yetis to be on. The Universe is very big and ET or God could be anywhere you’re not looking. No amount of evidence or lack of evidence can defeat the determined believer’s faith.
You could try to prove that the belief itself is absurd and fundamentally unsound. Good luck with that.

[Bolkonsky]

While your title is mostly correct, the article isn't. And it's not germane to the title.

It's founded solely on the assumption that God has no definition, and isn't actually about the title. In Judaism and Christianity, God does have a definition. The thesis of the article seems to be that God isn't defined, so you can't prove that God doesn't exist. If I were to submit that article, with the title of this thread to my teacher, I would probably lose at least 20 points for not sticking to my thesis statement. I will refute the whole theory of this article with one simple, universal (I would say Catholic, but it means the same thing) definition.

Notice how the author uses God, not god. Well clearly, "god" is a common noun, which has a definition.

the supernatural being conceived as the perfect and omnipotent and omniscient originator and ruler of the universe; the object of worship in monotheistic religions
deity: any supernatural being worshipped as controlling some part of the world or some aspect of life or who is the personification of a force
a man of such superior qualities that he seems like a deity to other people; "he was a god among men"
idol: a material effigy that is worshipped; "thou shalt not make unto thee any graven image"; "money was his god"

God, with a capital G is a proper noun. It is the name of one "god" - the god of the Christians and the Jews. His name is just "God"

So in essence he is a god who's name is God. It'd be no different than if my name was Human. I would be a human who's name is Human. And yes, "God" does have a definition.

Baltimore Catechism, Part 1, Lesson 1, Question 2:

Who is God?
God is the Supreme Being, infinitely perfect, who made all things and keeps them in existence.

As you can see, God is defined there, in a very simple sentence. There's more detailed definitions, in more detailed catechisms, but I chose this one merely for the simplicity. Now that I've cleared up that, the article become irrelevant. Let's remove everything that is based on the unfounded assumption that God has no definition.

“You can’t prove a negative.”


People who are searching for excuses to believe silly things frequently make this statement. A theist makes a positive assertion, and then declines to provide a basis for it. You deny their assertion (rightly so, what with no basis and all), but your denial is deemed invalid because it is impossible to prove a denial.

There is so very much wrong with this situation, it will take a while to wade through it.

The rules of logic and science indicate that there must be some kind of basis (either in substance or in thought) for an assertion or else it must be denied. An assertion, without evidence, is not accepted as true. That is the default position, the position that defines what critical thought is. Critical thought means not believing things you are told unless there is evidence to back it up. And without critical thought, logic and science are abandoned, and this is the only kind of productive thought humanity has ever come up with. To reject critical thought is to turn one’s back on thinking and embrace the Dark Ages. That’s the answer to this statement in theory.

However, in practice, there is usually a lot more happening with the person who makes such a proclamation. The person who makes this kind of statement has a great many fundamental misunderstandings about the nature of logic, science, and productive thought.

First, many people who believe in God do not realize that in every discussion about theism, their assertion is implicit: God exists. They do not need to say it. Every argument they make is under the assumption that the statement “God exists” is true. The fact that they identify themselves as believers is enough to serve as an assertion that a deity or deities exists. No assertion is being made by an atheist (at least not a smart atheist). The word “god” hasn’t even been defined and the nature of belief in that god has not been described; these must take place before any substantial discussion about the nature of God can begin. Atheists have no reason to provide these descriptions – without any beliefs about God, they have no reason to do so. It must be presumed that this onus rests upon the theist. The mere mention of one’s belief in God serves as an assertion that God exists.

Secondly, a person who rejects an assertion does not need to provide any justification for it. The evidence has to be provided by the party making the assertion. The person rejecting the assertion needs to provide nothing at all. Many theists try to escape this basic fact of life by declaring (in opposition to common sense) that their assertions need to be justified only to themselves in their personal experience. Simply put, that what is true for others might not be true for themselves. But this is madness – this also turns its back on productive thinking. This idea is called “solipsism,” and it refers to the notion that every person lives in his own reality, and what is true in his or her life might not be true for others. This is an old idea and it was shown to be ridiculous many centuries ago. Think about it – if it solipsism really was real, there wouldn’t be any books, schools, learning, or science. And people would never be able to communicate effectively.

Thirdly, the statement that “you cannot prove a negative” is simply false. On the surface, it seems to be true: if Person A says “I think God exists” and Person B says “I don’t think God exists,” it’s pretty clear that Person B is going to have a hard time proving that there isn’t a God. However, if you look a little closer, it actually depends on the nature of the negative statement being made. Here are some negative statements that can be proven very easily:

Five is not equal to four
The ancient Egyptians did not watch Seinfeld
The tsetse fly is not native to North America

Clearly, it’s possible to prove a negative statement. The real problem here is clearly the nature of the positive statement being refuted. When a person asserts that God exists, he does not specify the nature of God – that is, is God small, large, blue, red? And where is he? Of course it is not possible to prove that God does not exist, if “God” is a thing that has no definition, no characteristics, and no location. In fact, you can prove just about any kind of negative you can think of – except for (surprise!) the non-existence of mystical beings. When you get right down to it, the statement “you cannot prove a negative” is really just a different way of saying “You can’t prove me wrong because I don’t even know what I’m talking about.”

Logical statements have to abide by certain rules and restrictions. In order for a statement to be logical, it must be falsifiable, which means that it has to be presented in such a way that it could be proven incorrect. A statement is not logical if it cannot be tested to make sure it is true. The existence of God is not a logical question at all, and is therefore nonsensical. Of course you can’t prove that God doesn’t exist – no one even knows what God is supposed to be.

So now that I've removed the irrelevant, unfounded parts of the article, we're lefty with merely the beginnings of what could have been a good article, but went on a tangent, and derailed itself. I'm not saying that there is, or isn't a god, be it God, or Allah, or whoever the heck else people decide to worship. That's another discussion for another time, and another place.

Can you prove something that is negative? Yes. Should you be required to, in a logical argument? You can be. It works like this:

I go up to Denny and say:

"The Yankees won the world series."

And he says:

"No they didn't."

I shouldn't respond with:

"Prove they didn't."

That's asking for negative proof. Rather, I should be able to support my statement, by proving that they did. This article does not seem to be as much about negative proof as it is about refuting the arguments of theists. If I challenge you do a debate, saying that God exists, and you accept, I should be able to prove that God exists. If you challenge me to a debate saying that God doesn't exist, you should be able to prove it.

[chriscase]

The article is easy to read and manages to tackle the topic without becoming overly technical or making any glaring mistakes. I like QualiaSoup's video for greater clarity on a few points.

I think the point about "proof of a negative" is not only, as the article puts it, "the nature of the positive statement being refuted," but specifically that the statement being refuted is an existence statement. In a vast universe where the longest reach of our observation can only span the tiniest portion of existence, a well-defined entity may exist and not yet have been observed.

The point about poorly-defined entities is that they are necessarily unobservable. Invisible unicorns, beds made of sleep, and other absurd objects could be sitting right in front of us, but we wouldn't be able to tell because by their definition these things are not coherent and therefore unobservable. This is why a theist's insistence on being given proof that their poorly-defined, absurd God does not exist is not only logically unsound, but patently unfair. It's akin to allowing a murderer to go free because his victim is not alive to testify at the trial.

The thesis of the article seems to be that God isn't defined, so you can't prove that God doesn't exist... And yes, "God" does have a definition.

But the problem with most Christian definitions is that they are logically inconsistent. For instance, both definitions you cited as examples.

Absolute omnipotence is absurd, as is the notion of a perfect being that needs to be worshipped.

Of course, if I define God as "a big yellow ball that appears in the sky on a clear day," then the existence of God is a straightforward proposition. But the prevailing Christian definition is like an escape artist that's had two thousand years' practice squirming out of any reasonable box we might try to put it in. That's why it really should be disqualified from existence on the grounds of poor definition.

[Bolkonsky]

The article is easy to read and manages to tackle the topic without becoming overly technical or making any glaring mistakes. I like QualiaSoup's video for greater clarity on a few points.

I think the point about "proof of a negative" is not only, as the article puts it, "the nature of the positive statement being refuted," but specifically that the statement being refuted is an existence statement. In a vast universe where the longest reach of our observation can only span the tiniest portion of existence, a well-defined entity may exist and not yet have been observed.

The point about poorly-defined entities is that they are necessarily unobservable. Invisible unicorns, beds made of sleep, and other absurd objects could be sitting right in front of us, but we wouldn't be able to tell because by their definition these things are not coherent and therefore unobservable. This is why a theist's insistence on being given proof that their poorly-defined, absurd God does not exist is not only logically unsound, but patently unfair. It's akin to allowing a murderer to go free because his victim is not alive to testify at the trial.


But the problem with most Christian definitions is that they are logically inconsistent. For instance, both definitions you cited as examples.

Absolute omnipotence is absurd, as is the notion of a perfect being that needs to be worshipped.

Of course, if I define God as "a big yellow ball that appears in the sky on a clear day," then the existence of God is a straightforward proposition. But the prevailing Christian definition is like an escape artist that's had two thousand years' practice squirming out of any reasonable box we might try to put it in. That's why it really should be disqualified from existence on the grounds of poor definition.

Want me to define God for you? It's as simple as defining me, or you, or any object.

I even stated the Catechism's most basic definition of God. No inconsistency there.

Besides, I still stick to my point: The article and the title do not go hand in hand. This is an attempt to disprove God, under the pretext that the idea of God does't exist. To say that's it's an article about proving negatives is far from the truth.

[chriscase]

Want me to define God for you? It's as simple as defining me, or you, or any object.

Go for it.

I even stated the Catechism's most basic definition of God. No inconsistency there.

This one?

God is the Supreme Being, infinitely perfect, who made all things and keeps them in existence.

An "infinitely perfect" being? And you claim this is well defined? If we were to go looking for a being that has any measurable properties, "infinity" is not a well defined measure. There is no way to measure something that has "infinite" proportions.

And "perfection" is what, exactly? A matter of opinion? Besides, you seem to have missed my earlier argument that a perfect being that needs to be worshipped is self-refuting.

The rest of the "definition" fails to add anything other than a claim that something created the universe. The creation claim adds nothing to the already self-refuting definition besides an additional, unsubstantiated claim.

Besides, I still stick to my point: The article and the title do not go hand in hand. This is an attempt to disprove God, under the pretext that the idea of God does't exist. To say that's it's an article about proving negatives is far from the truth.

Yeah, I didn't say it deserved a Pulitzer Prize or anything like that. It's more of a sidebar, attempting to hone in on what often appears as a derail discussion in many theist/atheist debates. Like I said, I think QualiaSoup did a better job.

[Blau&Gruen]

If I am not mistaken, then "You can’t prove a negative" is an argument that describes negative requirements for a proposition (A).

A is true, when not true
- 1. A is implicit assertive
- 2. A is a solipsism
- 3. A is false


When a positive proposition is neither implicit assertive, nor a solipsism, nor false, then a proposition satisfies the requirements that allow tests that can lead to a verification.

[chriscase]

If I am not mistaken, then "You can’t prove a negative" is an argument that describes negative requirements for a possitive proposition (A).

A is true, when not true
- 1. A is implicit assertive
- 2. A is a solipsism
- 3. A is false

When A is neither implicit assertive, a solipsism, nor false, then A is true.

Would you mind walking me through that one in a bit more detail? An example and counter-example would be helpful.

[Boer]

I'd say this article is suited to deal with the cosmological argument, which seem to be where theists retreat when really confronted on their definition of god.

From my experience, if some one starts out with a fairly specific description of god (created the world and the animals in their current form 6,000 years ago, caused world wide flood 4,000 years ago, ect) and are confronted with specific evidence (for the age of the earth/universe or for evolution or against the flood) they have a tendency (assuming they don't simply ignore the evidence or call it all fraud) to revert to something along the lines of "everything needs a cause: must be god" or "who/what caused the big bang: must be god" or "god is beyond science/human understanding; we can't know the mind of god." Then there are those who start off with "everything exists, that proves god." It is against these types of arguments (if they can be called arguments) that the OP becomes relevant.

[removeduser_4536284751384]

Actucally I think this needs to differentiate between just anybody prooving negatives and an omniscient prooving negatives.

You can't proove that I didn't eat ice cream today, although an omniscient observer can. So one can, you probably can't.

[Denny Crane!]

Of course the title and the article go hand in hand. The title refers to the oft used retreat by the theist to the atheist about the fact that you can't prove a negative and then the article addresses the issue at some length. As Chriscase says it isn't exhaustive but it does the job.

[Blau&Gruen]

I had an interesting sequel of the discussion on pm with Chris. Of course I cannot post it, unless he would give the permission. I think, he has convinced me that we have to do with a problem of empirical existence assertions here. The atheism vs theism debate may just be a very special case in this context. And yes, the title and the article match well. I personally find the atheism vs theism debate a bit overdone but as a funny case example it may make sense but it can be substituted, e.g. with "phenomenology is a science" vs "phenomenology is not a science" or similar examples.

[Denny Crane!]

I had an interesting sequel of the discussion on pm with Cris. Of course I cannot post it, unless he would give the permission. I agree with him that we have to do with a problem of empirical existence assertions here. The atheism vs theism debate may just be a very special case in this context. And yes, the title and the article match well. I personally find the atheism vs theism debate a bit overdone but as a funny case example it may make sense.

A bit overdone maybe but of more social import than many more esoteric debates and it certainly holds more emotional content.

I'd be interested in the conversation, I've got no problem as yet with assertions based on empiricism.

[Blau&Gruen]

A kind response, thx. I think, we need to wait for Chris.

[Himster]

I can prove that I don't not have hair.

[Blau&Gruen]

I mean he argues for: It's not true that "You can't prove a negative" is true. -> He can prove that his statement is false.
It would be in your example: It's not true that "I can prove that I don't not have hair" is false. -> You can prove your physical attribut to have hair.
If I am not mistaken.

[chriscase]

The propositional form proposed earlier by B&G has three equivalencies for a proposition A:

A is true <=>
NOT (
( A is implicit assertive )
OR
( A is a solipsism )
OR
( A is false )
)

(Not totally sure whether the logical connector on these conditions is OR or AND...?)

The first thing that jumped out to me was that condition three appears to be both necessary and sufficient to the equivalency.

A is true <=> ~( A is false )

That's a basic identity of propositional logic. (The "~" means "NOT".)

The other two conditions would appear to be special cases of the third one, though they are not familiar to me.

The doubt I have about treating the question of proof of negative in purely propositional terms comes from this basic form. Given some propositions A and B such that A = ~B, we can also conclude that B = ~A. Thus there is nothing special about A versus ~B. They are logically equivalent, with the same properties - including difficulty of proof - regardless of whether the proposition is represented as a negation. So there must be something more specific about the definition of this negative proposition we are talking about that causes it to be difficult to prove.

What I think we are talking about here is a negative existence statement, where the existence statement cannot be proven deductively (as in mathematics), but must be verified inductively by empirical observation.

This is where an asymmetry in the existence statement with its negation becomes apparent. If we posit, "there exists a unicorn that eats candy corn and gives rides to small children," it would be easy to prove this statement, provided we can actually define the measurable properties we are looking for (what I call a "logical instrument" to detect the unicorn), and provided we actually make the associated observations. It is, however, virtually impossible to disprove this statement, because, unlikely as the unicorn's existence might be, the universe is just too vast for us to search it exhaustively to verify that such a creature definitively does not exist anywhere, on any scale.

Edit: It's also clear that if we impose enough spatial constraints on the existence statement, it will become easier to disprove, for instance, if we were to add that the unicorn must be the size of a grown horse and currently be living on planet Earth, it becomes more practical to disprove the existence statement. However, until the spatial requirements cause the logical instrument to be self-contradictory - for instance, if we require the horse-sized unicorn to be found in a sewing thimble - the negation cannot be considered definitively proven.