Burden of proof
Etymology
A rendering of the Latin legal maxim “onus probandi,” literally “the burden of proving.” Rooted in Roman law, it carries the principle that “he who asserts must prove,” and in criminal law it places the burden on the prosecution to overcome the presumption of innocence.
noun phrase · /BUR-dun uhv proof/
The obligation to provide evidence for a claim, which falls on the person asserting it, not on those who doubt it.
What it names
Names who has to make the case — a rule that decides an argument by default when neither side fully proves it.
Example
When someone claims a hidden conspiracy, the burden of proof is on them to show it, not on you to disprove it.
Related idea
The burden of proof says who must supply evidence; the appeal to ignorance fallacy tries to dodge it by treating “not disproven” as “proven,” and reasonable doubt is the specific bar the burden must clear in a criminal trial.