In an island peopled by Knights (who always say the truth) and Liars (who obviously always lie), two persons spoke about each other.

A said: "B would say I lie."

B said: "That is true."

Can anything be deduced as to what kind is each of them?

A's statement is clearly false, since B does in fact NOT say that A is lying. So A is a liar.

Since A's statment is false, and B claims it is true, B is also a liar.

So both are liars.

What if A had said "B would say I speak the truth" or B had said "That is a lie", or both?

Posted by Brian Wainscott on 2003-10-01 11:43:27