Barber Paradox (Russell's Paradox) - Back to the Paradoxes
Analogue paradox to the paradox of liar formulated English logician, philosopher and mathematician Bertrand Russell.
There was a barber in a village, who promised to shave everybody, who does not shave himself (or herself).
Can the barber shave himself and keep the mentioned promise?
Yes, if the barber shaves himself, then the barber has shaved himself, and the barber does not then need to shave him. Conversely, if the barber has not shaven, then the barber will take the liberty of shaving himself for himself. Then, the barber will have shaved himself, and the barber need not then to shave him.
Edited (better wording?):
In a village, the barber shaves everyone who does not shave himself/herself, but no one else.
Who shaves the barber?
Nobody shaves the barber. This is why you should read carefully before you enter into contract. Lesson learned.