A barber shaves only those people in the city who don't shave themselves. Does he shave himself? Why?

You are just a paradox, and it happens to be the most famous logical paradox: Barber Paradox put forward by Bertrand Russell;

The signboard of a barber shop reads:

Note: I shave all the men in the city who don't shave. I only shave these people.

Who shaves the barber?

If he shaves himself, he belongs to the kind of person who shaves himself. However, his sign says that he can't shave such people, so he can't shave himself. If another person comes to shave him, he is a person who doesn't shave himself. However, his sign says that all these people should be shaved, so no one else can shave him. This barber seems to have no one to shave!

Bertnard Russell put forward this paradox in order to express a famous paradox he found about sets in a popular way. Some sets seem to be their own elements.