There is one area in ethics where I think that the Judeo-Christian commandments provide better guidance than modern terminology. We recognize a modern moral prohibition against lying. The Biblical commandment, however, says that it is wrong to "bear false witness". Between the two, we would be better focusing on the biblical prohibition than on the the narrower constraint against lying.
What is the difference?
I would define a lie as an utterance that aims to cause somebody else to accept a proposition that the person making the utterance knows to be false. “Paul robbed the liquor store” spoken by a person who knows that Paul did not rob the liquor store is a lie.
"Bearing false witness" is an utterance that aims to cause somebody to accept a proposition that is false.
The difference is that the person who is bearing false witness does not have to be aware of the fact that the proposition is false to be guilty of a moral transgression.
For example, assume that I hear that Paul robbed a liquor store last night. I do not like Paul. Because of that dislike, I enthusiastically accept anything that anybody says about Paul that is bad. I also want others to dislike Paul. Therefore, as soon as I hear the story that he robbed the liquor store I believe it, and I start telling other people what (I believe) Paul had done.
If I were to do this, I would not be lying. My statements do not count as a lie because I actually do believe that Paul robbed a liquor store.
However, let us assume that the story is false. A friend of mine, while watching the news, saw video camera footage of a suspect in a robbery and decided that it looked like Paul. He told me about his suspicions, and I immediately jump to the conclusion that Paul was the person who committed the crime, and I immediately start telling everybody I know.
In doing this, I would be guilty of a moral transgression. I am not lying, but I am also not acting the way that a person of good moral character would act. I am bearing false witness against Paul, since I am testifying to everybody who listens that Paul has done something that Paul did not do, and which I have no good reason to believe that he did.
The Biblical language captures the moral prohibition more accurately than the claim that it is wrong to lie.
I can illustrate the difference by looking at the prohibition against killing an innocent person.
This prohibition does tells us that killing an innocent person is wrong, even if we do not know that he is innocent. To avoid the wrong of killing an innocent person, this prohibition tells us that we have an obligation to make sure that he is not innocent. We are not morally permitted to kill a person just because we think he is guilty – we have an obligation to make sure of this.
Let us say that I do not like Paul. Because I am suspicious of him, I form the idea that he is going to set fire to my sister's house tonight while my sister and her family are asleep. In order to preempt this attack on my sister, I go out and kill Paul. Of course, I claim that I act from the most virtuous of motives – my desire to protect my sister and her family.
However, Paul had no intention to attack my sister. He did not even possess the materials that would allow him to do so. I drew the conclusion that he was a threat to my sister based on a story that I constructed around a bunch of unrelated facts and rumors that I had decided to accept even though they were unfounded and uncorroborated claims. I embraced the theory that Paul was a threat to my sister because I wanted to believe this – because, if it was true, I could kill him, and not be guilty of murder.
In fact, let us say that I hated Paul so much, and I wanted a reason to kill him so badly, that I actively sought evidence that he was a threat to my sister and her family. In my search for evidence I cherry-pick the evidence. I accept as fact whatever I can weave into a convincing story, and reject that which counts against my theory. This is not conscious deception. Since I have drawn the conclusion that Paul deserves to be killed, everything that supports that conclusion has merit, while everything that is inconsistent with that conclusion is clearly unreliable.
If I was to think this way, and I was to kill John, I would be guilty of the moral crime of murder. No doubt, I would spend my time at the trial and in jail insisting that I was motivated by a concern for my sister. This is what I would want to believe of myself, and what I would want others to believe of me. However, the fact that I had accepted the conclusion that John was a threat based on such poor evidence shows that concern for my sister was a cover – a psychological defense – for more sinister motives that I would not want to admit, even (perhaps) to myself.
A jury of impartial observers would see through this. Recognizing that I formed my belief on flimsy evidence, they would conclude that I was guilty of murder. At best, I may be able to argue that I was not guilty by reason of insanity. However, unless the evidence would have convinced a rational and impartial person that John was a threat, I have no basis on which I can claim justifiable homicide.
The prohibition against bearing false witness, like the prohibition against killing innocent people, implies an obligation to make sure that our beliefs are true before we act on them.
It is not enough to believe that Paul is going to set fire to my sister's house. I have to have good evidence for that belief.
Similarly, I cannot claim to be innocent of "bearing false witness" when I said that Paul robbed the liquor store based solely on the fact that I believed it at the time. I also have to show that the belief itself was reasonable. I have to be able to show that I was not motivated by my hatred of Paul to accept weak evidence, but that even somebody who did not hate Paul, if given that same evidence, would have formed the conclusion that Paul robbed the liquor store.
Otherwise, I am guilty of the moral crime of bearing false witness against Paul.
People make mistakes. A woman, alone at home with her children, receives a series of threatening phone calls from somebody who is claiming to be on his way over to kill her and the children. She has called the police, but she lives quite some distance from town. Rain and mud make means that she will not see them for quite some time.
In the darkness, she sees somebody coming up her walkway. She shouts at the stranger to go away, but the stranger persists. She does not realize that the storm had forced the stranger's car off the road. The stranger’s child is laying back at the car badly injured. The stranger insists on getting in, so she shoots him, and kills him.
She kills an innocent person.
If she is a person of good moral character, the truth will have a devastating effect on her once she discovers it. However, mistakes happen, and innocent people are killed without the killer being a moral monster.
Mistakes may also lead a person to bear false witness against another without being immoral. However, the person who realizes he has made such a mistake, if he is a person of good moral character, will still feel the moral sting of discovering he has done something he should have done. He will seek to make up for it, even if it was an innocent mistake.
In the absence of these symptoms, we are justified in assuming that the agent really did not have much concern over whether he was doing the right thing. We have reason to suspect that we are dealing with somebody who does not have the regard for truth that he should have. The person who too eagerly embraces falsehood and accepts it as true cannot truly be said to be faithful to the value of truth.