You meet three blonde women, A, B, and C. Each of them is either a knight or a liar. Exactly one of them is Elle Woods.
A:I am Elle Woods.
B:I am Elle Woods.
C:At least two of us are liars.
What are A, B, and C, and who is Elle Woods?
On inspection we see the possibility that A and B are liars, C is telling the truth and C is the real Elle Woods. Also it's the only possibility that allows itself to be unique as any logic leading to either A or B being the real Elle Woods would also apply to the other in that pair.
But to actually eliminate that possibility logically, just assume that A is the real Elle Woods. Then B would be lying and you'd have the paradox that if C were telling the truth she'd be lying, but if she were lying, she'd have to be telling the truth.
So indeed C is the real Elle Woods and A and B are lying and C is telling the truth, as the only knight.

Posted by Charlie
on 20161219 10:31:34 