Burden of proof (philosophy)

Actually, you can prove there is no unicorn in the box by proving the positive: There is nothing in box. But you are correct, you don't prove negatives.

 

you can't prove "nothing" though. I know what you are trying to get at, but it's not quite correct. You can only prove positives, which is my main point.

 

No more so than you had done with the negative scenario. It is based on the exact same reasoning. If I don't see the unicorn, someone can propose a new reason why by adding a new variable (What if the unicorn is microscopic!). If I do see it, someone can propose a reason why by adding a new variable (It could be a hallucination!).

"We can't factor in all variables" applies to both situations. There could always be another reason why I'm not seeing the unicorn. There could always be another reason I am seeing the unicorn.

Like the Matrix. Where everything I think I'm experiencing is actually a simulation.

 

Rahl,

I do not wish to belabor the point. Leave it at a disagreement, have a good dinner, and let reality to the final judge. I do have one question though, are you a supporter of the chaos theory, you can't possible know everything about anything because of too many variables to consider? Just wondering. It sounds like their argument.

 

yes, as I didn't change any variables. I pointed out you can't know all the variables.

but the result of seeing it could be repeated, if indeed it was in the box. You could have more than one person see it.

no it doesn't.

 

fair enough

 

That only applies to nonfalsifiable claims. In logic, there is no grand distinction between negative and positive claims. Each can be rewritten as the other. Any statement can be written as an A or a - A. In reality, the same issues of a lack of perfect knowledge apply to each.

 

No, there is most certainly a distinction between a positive and negative claim.

 

You introduced variables that weren't in the original statement. Which is fine because that is part of your point. You cant know all of the variables, so someone can always introduce a new on to turn the "proof" on its head.

In which case we could both be hallucinating, or we could be being manipulated by another force, or another magical being could be disguised as a unicorn, or the other person could just be lying to me, or I could be imagining the other person as well, etc. etc. Same thing as "but what if the unicorn is microscopic."

I'm not sure how you could possibly convince yourself of that fallacy.

 

Dumb indeed

 

Ok.. As you say, fair enough.

 

And any claim can be written as a positive or a negative. I've tutored logic 101 for years. This is the sort of stuff that is in the first chapter of the book 99.99% of the time.

 

pointing out we can't know all variables, isn't introducing new variables.

none of this has anything to do with my statement.

it isn't a fallacy

 

no, you can't rewrite ANY claim as a positive or negative.

 

It is when you introduce new variables. A microscopic unicorn was not one of the original variables.

It is a list of variables you didn't account for which call your conclusion into question, just like your proposal of that the unicorn is microscopic. It is literally the exact same reasoning.

It certainly is. You are claiming that you can account for all variables and have prefect knowledge of them in the case of a positive claim, but the opposite is true in a negative claim. But this thought is your own invention. It appears nowhere in logic.

 

Yes, you can. Logic 101. Seriously, dude, how do you not know this? You are a smart and educated guy. Take "God does not exist" for example. It can be written as A (where A stands for "God does not exist") or - A (where A stands for "God does exist")

 

You surprised me with that, it was a very good post.

 

Yeh I pulled that card on Joe, its not that a negative cant be proven, that is a nonacademic myth, its that a negative can be extremely difficult to prove and require a lot of work, often time more than its worth for court cases as an example even using obversion or in combination with contraposition.

 

That isn't what I'm talking about. You can't rewrite the negative claim "there are no unicorns in this box" to be a positive. You also can't rewrite the claim "god does not exist" to be a positive.

 

thats what he said, then you have to prove it LOL

 

You must love parables.

This can be called the parable of the $150K house.

 

Then we are talking about different things. I'm talking about formal logic. Any claim can be expressed as a positive or negative in formal logic. And once it is expressed, the formal logic doesn't care about its contents. The proofs work the same way.

Premise: If A, then B.
- B
Therefore, - A

Logicians prove negatives every day, and it doesn't matter whether the claim represented by the variable is an informal negative or an informal positive. Both can be, likewise, invalidated in exactly the same way: by challenging the proof of the premise. That's what was going on when you brought up the microscopic unicorn. That's what I was doing when I brought up the brain in the vat. We were both going back to the "If A, then B" premise and poking holes in it. We were both saying that B could be false even if A is true.

First formulation:

If there is a unicorn in the box, I'll see a unicorn when I open the box.
I didn't see a unicorn when I opened the box
Therefore, there is no unicorn in the box.

Counterexample: But what if the unicorn was microscopic? Then you would not see a unicorn in the box when you open it. Your premise could be wrong. You aren't accounting for all variables

Second formulation:

If I see a unicorn in the box when I open it, there is a unicorn in the box.
I see a unicorn in the box.
Therefore, there is a unicorn in the box.

Counterexample: But what if the unicorn is a hallucination? Then you would see a unicorn in the box even if there wasn't really one there. Your premise could be wrong. You aren't accounting for all variables.


It isn't every day . . . or every decade . . . that I agree with Koko. But there are no special rules here for negatives in formal logic. Once expressed as a variable, they all follow the same calculus.

A claim is any statement that can be true or false. Regardless of content. And all claims follow the same rules in logic. It doesn't matter how many negative terms the claim contains.

 

Well, if it's somehow not in the visible light spectrum, then it's not visible, so that's not answering the question. I'm asking about a visible unicorn, the visual light spectrum is all I need.

 

Not really. If I want to know about the unicorn in the box, I have not interest in any unicorns or anything else outside the box. I know what I mean by "is" (for instance, I could tell if there was a pea in the box), I know what a unicorn is (close enough, I could define it better if that had been important for the argument, but it is not), the true nature of reality above that is of no use to me.