Your point (assuming we're not treating seriously the argument to popularity) seems to be that if a person believes something thinks something exists, then they are under no obligation to prove to anyone else that what they think exists actually does.
No, that position is much stronger than what I endorsed. I was only making the claim that in
some circumstances the burden of proof lies with the person making the non-existence claim. I did not endorse that the burden of proof is equal in all situations or that there is never a burden to prove an existence claim.
You bring up Unicorns, and that plays right into what I think is the better requirement. Again, I'm a Bayesian when it comes to evidence and burden of proof. That means, the person making the
stranger claim has the burden of proof, or in other words, the claim that has the lower prior probability. I am only claiming that this is not ALWAYS the non-existence claim.
Of all the things that influence who has a burden of proof, the "making an existence claim" is either giving no or very little weight to who has it. Other things are much more important.
The reason I am arguing this is because I don't think theists have the burden of proof
because they are making an existence claim. They have a greater burden, but not for
that reason. So bringing up unicorns doesn't really help point out the difference between existence/not existence claims.
For example, what about conspiracy theories? If I say there wasn't a moon landing, or there was no 9/11 attack, or there is no president, I have the burden of proof because I am making improbable claims.
Now to Azdgari:
Can we prove that the laws of physics as we observe them apply equally everywhere? No. It's a reasonable inference that they do, but it is not proven as a matter of formal logic. And that's what we're talking about.
You just raised the standard way too high. By that standard not a single scientific claim counts as proven because science proceeds by abduction (or induction), not deduction. Just because we measure gravity every time we measure for it does not, by deductive logic, prove that it ever holds anywhere or anytime we haven't measured. If you throw out induction you should be a skeptic about pretty much everything besides your own existence and theorems in math derivable from axioms.
Do you have some alternate way that you can say that physics works in your backyard but not on the other end of the universe? Both are inductive claims, so just denying induction isn't going to get you what you want.
"Exist" is a category error when applied to such things. Events happen to things that exist; they do not exist as entities in themselves. Facts are descriptions of what exists. Properties are...well, properties of things that exist (or that don't). Numbers are a way of describing things, not entities in and of themselves; their existence (or lack thereof) is as subjective as anything else I've listed. Same with sets.
You don't just get to say that, you have to make an argument. you
can be a nominalist about so called abstract objects, but you better be ready to have a good argument.
When I say "exist," I mean what Quine meant by it. That is, "To exist is to be the value of a bound variable." As he would say:
Quine's slogan, "To be is to be the value of a variable," means that we only commit ourselves to an ontology by claims that say things like "There is something (bound variable) that is ..."
For example, "There is something that is a prime number greater than a million" commits us to believing that such numbers are entities. And "There is some property (or characteristic) that red houses and red cars have in common" commits us to believing that properties (or characteristics) are entities.
If you have a better definition of existence then W.V. Quine, go ahead.
Armed with this and the Quine-Putnam Indispensibility argument you get the following:
1. Quine's Dictum: To be is to be the value of a variable
2. Naturalism: We should believe in the entities of our best scientific theories
3. Indispensibility: Our best scientific theories quantify over numbers (e.g. there is gravitational constant that is ...)
Therefore,
4. Platonism: Numbers exist.
There are philosophers (well, there is one) who try to do "Science without numbers" [Hartry Field], but it's not looking good. And unless you can do that, 3. is true, I'm sure you want to endorse 2., and I bet you'd be hard pressed coming up with something better then 1.
So, sorry, numbers exist.
So it isn't true that in general it is impossible to prove that something is not anywhere at all. There have to be further restrictions.
As long as the subject in question is a "something", it applies. As you've said, when we're not talking about a "something", of course it doesn't apply.
Ok, first, I'm running out of vocabulary. I thought "something" was the most generic term I could possibly use that covers, aehm, (entities, principles, things??). I guess I will introduce the term "schmings" to mean even that which isn't a "thing," but also "things." You say "subject," but that just doesn't seem like the right word.
The only way I can read your last statement is by translating it thus then:
As long as a schming is a thing, it is impossible to prove that it does not exist (somewhere). Only for schmings that are not things can we prove that they do not exist.
But combining this with your statement about exist, you seem to further say "No schmings that are not things exist." I still don't know your definition of "thing" v.s. "not thing schming." Also, I don't know if you mean the same by "is" as by "exist." I don't know how you can say "3 is a prime" if you don't mean something different.
Please explain to me:
What are, to you "things," and what are not? How do you differentiate?
What does it take for "schmings" to exist? (And also, what does it take for "things" to exist?) How are your criteria for existence satisfied?
Anyways, hopefully still making progress.
