Thought experiment / duty

Kant at the Door

A murderer asks where his intended victim is hiding. Tell the truth, lie, refuse or intervene—and defend the rule behind the answer.

Script-free discussion

Five variables at the door

An uncertain threat
A frightened person is hiding inside. A visitor who has threatened to murder them asks whether they are there. The threat is credible, but you do not know whether the visitor will carry it out.
Changed variable: The threatened killing is credible but not certain.
Does uncertainty weaken an emergency exception, or strengthen the case for refusing to become part of the visitor's plan?
The threat is explicit
The visitor now states clearly that they intend to kill the person inside, and you know the person is still there. A truthful answer would tell the murderer where to find them.
Changed variable: The threatened killing and the relevance of your answer are now certain.
Kant denies that a benevolent aim creates a right to lie; critics ask whether truthfulness can require material cooperation with wrongdoing.
Silence now communicates
The visitor says: 'If you refuse to answer, I will take that as confirmation.' Remaining silent or simply refusing will now communicate useful information.
Changed variable: Silence and refusal have acquired a predictable meaning.
The distinction between lying, withholding and misleading becomes harder to maintain when every communicative act has effects.
Protection is available
A secure barrier and an emergency call point are within reach. Using them carries some personal risk and delay, but it could stop the murderer without answering the question.
Changed variable: A non-deceptive protective intervention is now realistically available.
A conflict between truth and protection may partly dissolve when action, rather than declaration, can answer the emergency.
Write the rule for everyone
Imagine that your policy will be publicly taught for comparable emergencies. Hostile visitors, protectors and bystanders will all know the rule in advance.
Changed variable: Your exceptional choice must now be stated as a public, repeatable principle.
Universalising a maxim asks more than whether one lie works; it asks what practice of declaration, refusal and protection can remain coherent for everyone.

The actual dispute

Will duty make you assist a murderer?

The murderer intends to kill the person hiding inside. A truthful answer gives him the information he needs. Kant nevertheless denies that a good aim creates a right to lie.

His argument is not “be polite to murderers”. It is that public truthfulness cannot survive if each speaker claims a private exception whenever deception seems useful. The law of right must be universal or it becomes personal licence.

The objection is savage: if your truth foreseeably helps a murderer kill, the purity of your maxim may be bought with somebody else's blood. Refusal, deception and physical intervention test whether duty protects persons or merely protects the rule.

All games

A hard case tests both the rule and the description of the act.

Moral Cartographer

Kant at the Door

Your decision record belongs in an argument with Immanuel Kant

Actions you chose

Reasons you used

What changed your answer?

Will duty make you assist a murderer?