When making a claim the onus falls upon you to provide evidence to support your position.
This is called the 'Burden of Proof'.
It is NOT the role of the person disputing your claim to provide evidence that disproves it.
Hitchen's Razor states:
"What may be asserted without evidence, may be dismissed without evidence"
- Christopher Hitchens
Shifting the burden
Sometimes people will attempt to shift the burden of proof by committing logical fallacies like making an appeal to ignorance.
Argument from ignorance: assuming something is a fact primarily based on lack of evidence to the contrary.
A proposition is assumed to be true because it has not yet been proven false or a proposition is assumed to be false because it has not yet been proven to be true.
Person A: I was harassed
Person B: Can you provide evidence of this?
Person A: I shouldn't have to, you can't prove that I wasn't harassed.
Person A: God exists
Person B: There's no evidence of that
Person A: There's no evidence that he doesn't
'I shouldn't have to do your research for you'
'Show me the evidence that it doesn't work'
'If you can't prove that it doesn't work then it must work'
'I shouldn't have to provide evidence, you should prove that what I'm saying is false'
When making claims you must be prepared to provide scientific reasoning for your stance.
Unsubstantiated claims and arguments that commit logical fallacies must be rejected.
"Extraordinary claims require extraordinary evidence"
- Carl Sagan 'The Sagan Standard'