Lying is an inherent part of human nature, and we do it for many reasons. Cain, the first human ever born according to the Bible, in essence lied to God, as did his father Adam. They had committed sins and were ashamed to admit to them. We know lying is inherent because no one has to teach little children to lie--they do it instinctively. We lie for myriad reasons, and sometimes we can even justify our lies. If they do not rise to the level of criminal behavior, the lies we tell have consequences that range from minimal to devastating.
While lying is, in my opinion, unethical, it is not a crime other than in certain specific instances mentioned in post #1 above. Some people believe that in certain cases that lying is also not unethical or immoral (such as the case when a woman asks you if her outfit makes her look fat), but in my opinion lying is always the wrong thing to do. Lying always comes back to bite one in the hind quarters, and one must have a very good memory to lie well. I don't even like the Santa Clauslie that parents tell their children. Although it seems harmless, I think it confuses children. Sometimes parents lie and it's OK, and sometimes it is wrong. Which is which? We never told our children Santa was real. We just told them that we were playing a game and someone in our family was playing Santa and they had to guess who.
As to why do people lie? There are many reasons...they want to look better in front of friends and would-be lovers, they want to get out of trouble, they want to get promoted or get into a good school, etc.
I think the context and interpretation of the situation becomes an important part of determining whether or not a given statement is a "lie" more often than we realize. Consider the policy statements issued by any political candidate. Such stances are frequently based on carefully selected facts, gathered and presented to support the politician's view on the given subject. In almost every case, it would be possible to collect carefully selected and equally valid facts to support a completely opposite point of view about the topic.
So, who is lying? Is anyone lying? Or does it become essential to look at the overall picture rather than isolating only certain aspects of a topic?
I think context is all important in determining whether telling a lie is a crime or not. I think obviously if you have sworn to tell the truth, and others are going to be impacted through your lie, then it can be judged a crime, but even then, it could be argued that there are some cases within this where it would be right to lie, such as Germans during the Holocaust who lied to protect Jewish families. This means that we have to take a look at each incidence based on its own context.
Your second question asked why do we tell lies. Well, there is a myriad of reasons for it:
1. To protect ourselves from consequences.
2. To protect the emotions of others who would suffer if learning a specific truth.
3. To cover up for someone else and protect them from consequences.
4. To purposely give false information in order to benefit or deprecate someone else.
5. As part of a problem of mental delusion where the person does not know that he or she is actually telling a lie.
Back to your first question, you asked when is lying a crime. I will have to support #2 in that, as long as it is a situation that occurs under oath and done with the purpose of complying with the law, you have the obligation of telling the truth. If you do not do that, you are literally committing a crime.
When you are placed under oath, in a deposition, an affidavit or in testimony on the stand, this is considered a crime. Lying in the course of an investigation in which you are not the suspect can be considered obstruction of justice, also a crime.
In general, though, lies are social crimes, of varying degree, sometimes simply to be polite, like telling someone their dinner was good when it wasn't. These are sometimes called "white lies". But lies that hurt other people, even if not as part of a criminal act, are still crimes against society.
I can't help but refer your post to the current Casey Anthony murder trial in Orlando, Florida. It is evident that Casey's dishonesty is of immense proportions, and though she may not be found guilty of first degree murder, she almost certainly will be found guilty of several perjury charges against her. Analysts suggest that she grew up in an environment where telling the truth was just not an important moral obligation; her own parents, Cindy and George, will also probably be charged with perjury for their many conflicting statements made to authorities. It seems that Casey never really learned the value of honesty as an essential part of a person's character, and she seems to have a different story for every situation that she confronts. Honesty and trustworthiness may not always be illegal (note the previous post concerning perjury and slander), but it is an important part of one's character. People who are known to lie repeatedly in order to cover up their own mistakes--or, in Casey's case, as a matter of routine--are not likely to be trusted in other situations, such as employment and personal friendship. Like the boy who cried wolf in Aesop's Fables, eventually no one will pay any attention to such a person, even when they really are being truthful or in need.
Lying can be a crime, but only in some specific circumstances. Two instances in which lying is a crime are:
- Perjury. If you are in court and you swear to tell the truth about something it is a crime to lie.
- Slander. If you tell a lie about someone in a way that can do damage to their reputation, you can be charged with the crime of slander.
But lying, in general, is not a crime. It may be immoral (though I would argue it is not always immoral) but it is not illegal.