Memory
Our memories are fundamental to who we are. All our knowledge and all our skills and other abilities reside in memory. As a consequence so do all our: beliefs; tastes; loves; hates; hopes; and fears.
Yet our memories are neither permanent nor unchangeable and this has many consequences. Not the least of these is the bearing memory has on our truthfulness.
According to the Macquarie Dictionary a lie is: "a false statement made with intent to deceive; an intentional untruth; a falsehood - something intended or serving to convey a false impression". So when we remember something that didn't happen, perhaps from a dream or a suggestion made by someone else, or we forget something that did happen, we are not lying when we falsely assert that it happened or truthfully deny it.
The alarming thing is that this may happen quite frequently without our noticing. Mostly this is trivial but when it contradicts someone else's recollections, in a way that has serious legal or social implications, it can change lives or become front page news.
Read more: Memory