Who gets to decide when someone is lying?

[Angrboda]

Calling something a lie, rather than simply false or wrong, implies an intention. Only the person doing the telling has sufficiently privileged perspective to say one way or the other as to intent. As a general rule, inferring intent from actions and circumstantial evidence is itself notoriously unreliable, and is also subject to the same type of confirmation problems as the original testimony. (Is the witness to the lie him or herself too biased to be reliable?)