Lying vs. Deception

A reader writes:

I’m writing a paper on the doctrine of lying for one of my graduate courses. I came across your blog post from February 2011, and under point 17 you say that there is confusion surrounding deception and lying: one being permissible, while the other is never so. Would you be kind enough to point me to some sources that give evidence to deception being sometimes ok? I greatly appreciate your help!

Thank you for your time, and peace be with you!

Here is what the Catechism has to say about lying:

2483 Lying is the most direct offense against the truth. To lie is to speak or act against the truth in order to lead someone into error. By injuring man’s relation to truth and to his neighbor, a lie offends against the fundamental relation of man and of his word to the Lord.

2484 The gravity of a lie is measured against the nature of the truth it deforms, the circumstances, the intentions of the one who lies, and the harm suffered by its victims. If a lie in itself only constitutes a venial sin, it becomes mortal when it does grave injury to the virtues of justice and charity.

2485 By its very nature, lying is to be condemned. It is a profanation of speech, whereas the purpose of speech is to communicate known truth to others. The deliberate intention of leading a neighbor into error by saying things contrary to the truth constitutes a failure in justice and charity. The culpability is greater when the intention of deceiving entails the risk of deadly consequences for those who are led astray.

2486 Since it violates the virtue of truthfulness, a lie does real violence to another. It affects his ability to know, which is a condition of every judgment and decision. It contains the seed of discord and all consequent evils. Lying is destructive of society; it undermines trust among men and tears apart the fabric of social relationships.

So it is lying to seek you out in order to present myself to you under a false identity, purpose and occupation. It matters not what good end I am attempting to achieve. I’m still lying.

However, it is not lying to not supply information to which somebody has no right. As the Catechism says:

2488 The right to the communication of the truth is not unconditional. Everyone must conform his life to the Gospel precept of fraternal love. This requires us in concrete situations to judge whether or not it is appropriate to reveal the truth to someone who asks for it.

2489 Charity and respect for the truth should dictate the response to every request for information or communication. The good and safety of others, respect for privacy, and the common good are sufficient reasons for being silent about what ought not be known or for making use of a discreet language. The duty to avoid scandal often commands strict discretion. No one is bound to reveal the truth to someone who does not have the right to know it.283

So in the classic scenario, when the Gestapo comes to the door looking for the Jews you are hiding, you have no obligation to tell them where they are. That’s not lying. It’s withholding information. The trick to saving your Jews is not to lie well, but to hide your Jews well. Then you invite the Gestapo in, give them a firm “Sieg heil!”, offer them tea and cookies, and make cheery conversation. None of that is lying, but it is allowing them to believe that you have fully cooperated with them, which is up to them. Deception is the art of allowing your enemy to fool himself without your lying to him.