Who gets to decide when someone is lying?

[Clueless Morgan]

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?)

I agree that calling something a lie implies intention to deceive, and in the case of Piltdown Man the perpetrator of the hoax (the person who forged the skull and jaw) was never caught or discovered so intention to deceive in this case is not clear. But intention to deceive can be inferred from the circumstantial evidence, can it not?

With that said, I will also agree that no evidence is ever perfectly reliable because there will always be an element of human subjectivity and error present to some extent. What you can have, though, is enough evidence to warrant justifying one side or the other of an argument - whether someone is or isn't lying. Isn't this how criminal trials work? Evidence that has been gathered is presented making a case for the imprisonment of a criminal; the prosecution either makes their case and the criminal is put away, or the defense sows enough reasonable doubt to get their client off. You could do the same thing in showing someone is lying; either the people with the evidence of the lie make their case with the evidence they have or enough reasonable doubt is present to refrain from calling the person a liar. Neither situation is air tight (an innocent person can still be imprisoned for a crime they didn't commit, just like an honest person can be accused of a lie they didn't tell) and no evidence is perfectly reliable, but you can gather a good (convincing) set of data that points to a particular conclusion, and you could have a lack of falsifying data to disprove your argument (evolution being an example of lots of positive evidence and no evidence falsifying the theory).

My original question remains, though: If a lie is perpetrated, the only person who could expose the lie would be the person who discovers the lie, again, assuming they were not in on the lie nor had prior knowledge of the lie. To be more encompassing, I suppose you could restate the argument as "The only person who could expose a lie would be a person who has knowledge of the lie" which would cover anyone who is in on the lie (a member of a conspiracy can rat on their fellow conspirators), has prior knowledge the lie is going to be perpetrated or is being perpetrated (maybe they overheard someone planning the lie or saw them carrying it out) and anyone who uncovers information a lie has been perpetrated after the fact (Weiner and Oakley uncovering evidence that Piltdown Man was a hoax years after Piltdown Man was discovered).

C'mon, Kichi, no help here?