Quote:

Hydra has fallen into the same fallacy as I discussed in the prior thread. You MUST have these statements coming from a trusted third party or they cannot be relied upon.



In the prior thread (q.v.), the "fallacy" you accuse me of falling into was, in fact, the answer I eventually gave to the question of why Sarah's formulation failed. Now, if I'd given away the answer in my first post, it wouldn't have been much of a riddle, would it?

Of course, I have already said this. But why let the fact get in the way of a riposte that makes you look clever?

However, in this case you are right. I recalled the riddle from memory, and made this mistake: that the information about the Knights in this problem is meant to be a known-known.

Mutatis mutandis, Alex Williams's solution is correct.

Quote:

Solution
It is day, and the knight was a Night-Knight. This is easily realised by tabulating all the possible of answers of Night-Knights and Day-Knights at night and during the day:

DAY
Day-Knight: 'I am a Day-Knight. It is day.'
Night-Knight: 'I am a Day-Knight. It is night.'

NIGHT
Night-Knight: 'I am a Night-Knight. It is night.'
Day-Knight: 'I am a Night-Knight. It is day.'