What does the phrase “you can’t prove a negative” actually mean?

Question

What does the phrase “you can’t prove a negative” actually mean?

In: 1149

Answer 1

It’s a matter of placing burden of proof.

You can’t prove there is no teapot on orbit around Mars. If I claim there is, how will you prove me wrong?

Well, you don’t have to, me claiming such would be ridiculous and it would be me who would have to be proving things, not you. Until I do my claims have no merit and can be disregarded as baseless.

Same thing if I claim I have a invisible dragon in my living room. You don’t have to prove that I don’t, it’s up to me to prove what I claim to be true is not complete nonsense.