What is truth? One person's view of something may be different from another's. What one says is not necessarily a lie, even though it may not appear to be correct from the other person's point of view. If there are various opinions on something, then one opinion cannot be a lie. If you are talking about FACTS, then someone could be mistaken. And even adults may be afraid of punishment, for instance of being prosecuted. They may not want to hurt someone else's feelings. There is also, of course, greed and the need to be liked and admired. So many reasons for seeing things differently from someone else or for saying that a fact is one thing when it is another.