The Catholic tradition takes the Eighth Commandment—“Thou shalt not bear false witness against thy neighbor”—extremely seriously. Strict condemnations of all kinds of lying can be found from the Fathers of the Church, notably St. Augustine (who wrote two short works on the subject), to the Doctors and the modern Magisterium. The act of lying is per se malum: it cannot rightly be done even for a good end.
One reason for this is that lying is contrary to the nature of God, who is Truth. It is of the utmost importance that we can believe what God tells us—both what he reveals about himself and what he promises to those who love and obey him—since this is the basis of the Christian life. God could permit the children of Israel to take others’ property, as when the Israelites conquered Canaan, because he is the primary owner of the whole universe. God could permit Abraham to kill Isaac, because all humans born in original sin owe God a life. But he cannot permit anyone to tell a lie.
Nevertheless, the question of exactly what lying is remains fraught. God appears to have rewarded the Israelite midwives who lied to Pharaoh to explain their failure to commit infanticide (Exod. 1:19-20). We might read this story as about God rewarding them despite their lying, but it is cases like this that cause the most problems: lying to protect the innocent.
The untruths of drama and fiction have also caused some confusion, but it is generally agreed that a stage play is not a lie, as there is no intention to deceive. Our Lord did not hesitate to use fictional stories to illustrate his teaching, and in presenting these parables, the Evangelists do not seem overly concerned about making disclaimers. It is just obvious that the Parable of the Sower is fiction; it has nothing to do with lying. The existence of conventions and reasonable expectations among an audience is as relevant to the question of telling the truth as the meaning of the words the performer is using, which is set by the way the words are used in a language community.
In a different way, a statement made with the intention to deceive, but that is not actually untrue, may be contrary to justice for a number of reasons, but it is not a lie. If the intention is to defraud someone or to lead him into some unjust harm, then that is enough to show that the action is wrong. In such cases, we might say that the person we are talking to had the right to know the truth, and you have wronged him by causing confusion. But what if he has no right to know the truth? What if he is demanding information to use unjustly, or something you are under an obligation to keep secret?
The story is told of the great St. Athanasius, on one of the many occasions he was obliged to flee persecution, rowing along a river to escape. Rowing in the opposite direction were a group of people searching for him, who called out: “Where is the heretic Athanasius?” It would have been a lie for him to have replied, “I don’t know” or to have given a false location. He replied, “He’s not far away” and kept on rowing.
During the English persecution of the late sixteenth and seventeenth centuries, the Jesuits became particularly associated with this approach and took it to rather extraordinary extremes. When challenged as to whether they were priests, for example, they knew that it was not just their own safety that was at issue, but that of every family they had stayed with in England—indeed, everyone who had so much as spoken to them.
Missionary priests like St. Robert Southwell and Henry Garnet wrote on the subject of lying, seeking a way to deal with the problem. They developed two related ideas. Equivocation is an ambiguous statement; mental reservation is an unexpressed qualification to what one is saying. We exercise mental reservation when, asked if we can “spare any change” by a beggar, decide that in the circumstances, it would not be prudent to give him money and say “no,” even if we have money on us. We mean more than what we explicitly say: something like “not for you.”
Under persecution, a refusal to answer a simple question might be tantamount to an admission of guilt, and Catholic priests in England would go so far as to deny being priests. They could tell themselves that, according to the Protestant theory of the man questioning them, the only true priest was Christ, and since they were not Christ, on the Protestant view, they were not priests. Or they might say “I am not a priest” with the mental qualification “of Apollo.”
(Pope Innocent XI put an end to the more extravagant growths of this line of thinking in 1679, but the debate has not entirely gone away.)
The Catechism of the Catholic Church defines lying by quoting St. Augustine: “A lie consists in speaking a falsehood with the intention of deceiving” (2482). This leaves open certain possibilities: for example, to say what is not true when there is no intention to deceive, as in a stage play.
We are not bound to tell the whole truth, and indeed such a duty would be impractical. On the contrary, we may be strictly bound to protect secrets, as priests are bound to protect the seal of confession. So in response to an unwarranted enquiry we may say something that is true but either gives a misleading impression or effectively changes the subject. How to do this best is not a matter of morality, but of verbal dexterity.
If the axe-murderer of the popular example is on your doorstep, demanding to know if your friend is at home—and he is—it may seem a bit tough to say that the correct way to deal with the situation is to tell the truth, but to do it in such a clever way as somehow to put the axe-murderer off the scent. We can’t have a moral obligation to be cleverer than we are. But we have the same difficulty when trying to save a friend from an unjust lawsuit or a life-threatening car accident.
Morality can alert us to courses of action that are ruled out; it is for us to make the best of the situation, choosing among the courses of action that are not wrong, and employing whatever skills, knowledge, and hard work we can.