Is deception in the name of God ever justifiable?

It’s a common complaint that Catholic pro-lifers while often quick to criticise pro-choice groups for stretching truths or disregarding legal propriety tend to gloss over their own failings.

Explosive internet debates about the Planned Parenthood sting videos, however, show just how false that allegation is. One Twitter thread alone has featured over 900 interventions between Catholics passionately debating whether it is ever justifiable to lie when human lives are at stake.

The pseudonymous ‘Ben Trovato’, author of, puts the question simply. “Clearly we should fight the evil abortion culture of deadly lies with every legitimate weapon available to us,” he says, “but is lying a legitimate weapon?”

Describing himself as torn on the issue, Ben observes that “it is a first principle of Catholic moral philosophy that we must not do evil in the hope of achieving good ends” and that lying is “a particularly serious type of sin” since it is “not just an offence against God’s law, and normally an injustice to our neighbour; it is also an attack on God, in so far as it is an attack on the truth”.


On the other hand, he notes, moral theologians allow deception in certain circumstances as legitimate, and is difficult to see moral distinctions between direct lies and deception by devious means.

Echoing Chesterton’s observation that “all sane moralists admit that one may sometimes tell a lie”, he says it “seems self-evident that to tell a lie in order to save lives is not a terrible thing to do”, observing that the classic example of “hiding Jewish people from the Nazis and lying when you get the knock on the door is hard to refute without great moral discomfort”.

In the end, the two principled positions seem to leave him paralysed, observing that “part of me knows what I would do, but I am also clear that we cannot deduce what we should do from what we would do”. 

The author of explores this idea further, recognising that the mainstream of Catholic theology and philosophy typically holds that a lie can never be justified, but highlighting an intriguing article in which Prof. Janet E. Smith analyses the significance of the first edition of the Catechism of the Catholic Church’s definition of lying as speaking against the truth in order to lead into error “who has a right to know the truth”. 

Pointing out that Catholic moral teaching cannot be reduced to a simple set of rules, and that natural law cannot be followed properly without cultivating practical wisdom, he ultimately concludes that this is a serious question of conscience, and one that cannot be resolved without much prayer, deep thought, and a humble willingness to engage honestly with the Church’s historical thought.