Thursday 15 October 2026

How it works

Every witness is either honest or a liar. An honest witness only says true things, and a liar only says false ones, like the knights and knaves in Raymond Smullyan's puzzles. Each of them makes one statement below. Your job is to mark every witness honest or liar so that all the statements hold up together. Exactly one way of doing that works, and you can reach it by reasoning alone: try a guess, follow what it forces, and drop it the moment two statements clash.

The statements

1. The DentistThe Jeweller is a liar, or the Locksmith is, or both.
2. The PostmanExactly three of us are liars.
3. The GardenerThe Dentist and the Postman are different kinds.
4. The JewellerThe Dentist and I are the same kind.
5. The LocksmithThe Gardener is a liar.