Derek asked:

I thought it was pretty obvious that Kant was a moral absolutist and really meant that one must not lie, at any cost. If an axe murderer came looking for a victim, and asked you where the intended victim was, Kant insisted one must not lie even to save his life.

But I was in a conversation the other day and the topic came up. My interlocutor insisted that Kant didn’t really mean what he said, but rather it was a ‘thought exercise’.

What do you think? Did Kant really mean that one should not lie, even to save a life?

Answer by Craig Skinner

You are right. Kant was a moral absolutist about this and meant what he said.

His critics found this hard line difficult to accept. One of them (Benjamin Constant) suggested a way out. He urged that a duty to somebody arises from that person’s right. So, the duty to tell the truth arises from the listener’s right to hear it. But the mad axeman has forfeited his right to hear the truth, so I have no duty to tell him it.

However, Kant stuck to his guns, saying that the duty was not one to the individual listener (or to oneself), but to humanity as a whole. He replied:

‘Truthfulness in statements… is the formal duty of man to everyone, however great the disadvantage that may arise therefrom for him or for any other’ (‘On a Supposed Right to Lie Because of Philanthropy’, 1799).

So, how to deal with the enquiring axeman?

We find the answer in what Kant did outside the study, rather than in what he wrote inside it – ‘by their deeds ye shall know them’, as the Bible rightly says.

Kant’s writings on religion annoyed the king who thought them disrespectful to Christianity. He demanded Kant’s promise there would be no further writing on the topic. Kant replied:

‘As your majesty’s faithful subject, I shall in the future completely desist from all public lectures or papers concerning religion’.

The king was satisfied. But Kant knew the king wouldn’t live long, and when he died, Kant considered his promise void because it only applied to himself ‘as your majesty’s faithful subject’ and, with the king’s death, Kant was no longer his subject.

So Kant didn’t lie, but told a misleading truth.

And so it can be with the axeman demanding ‘Is he inside your house?’ We can’t say ‘No’ (a lie). We surely can’t say ‘Yes’. But we can say ‘I spoke to him down the supermarket about half an hour ago’ or ‘He often goes to the pub at this time’ (misleading truths).

Or when my old aunt Agatha watches me unwrap her birthday gift to me, revealing a hideous shirt I will never wear, and asks me if I like it, I can say ‘Wow!, thanks a bundle’ or ‘ I’ve never seen such colourful checks’.

So, it’s no lies for the Kantian, but sometimes misleading truths are in order. And the latter, unlike lies, don’t produce such problems with Kant’s Categorical Imperative, and so fit in better with his philosophy, but I wont pursue the detail of that here.


Answer by Geoffrey Klempner

In Kant’s moral philosophy the Categorical Imperative is a law of reason, like the laws of logic. Telling a lie can never be the rational thing to do, even if there are very strong ‘reasons’ for lying because of the predicted consequences if you tell the truth. Kant makes the point that if you thought the intended victim went left when in fact he went right and told the would-be axe murderer, ‘He went right’, intending to lie but in fact stating the truth, then you would share responsibility for the victim’s death. (Try this thought experiment out for yourself and see how you would feel.) More generally, we can never be sure of the wider consequences of an act which was intended to do good. For example, the wider consequences of your being identified as a ‘person who is prepared to tell a lie, when it is expedient to do so.’

How to deal with the axe man? There are various possibilities. If I refuse to say to say anything but glance my eyes left (intending to deceive the axe man) that isn’t a lie, on Kant’s definition. Then again, whether I say ‘left’ or glance my eyes left, the axe man can reason that any normal person would try to lie or deceive in those circumstances, and go right. Or it could be a double-bluff. So this becomes an exercise in game theory. In a world where all our choices are determined by game theory (including the choice whether to tell the truth or tell a lie) something precious has been lost, the foundation of our ability to communicate with one another. That’s the point Kant is making.