Once upon a time there was a town with a perplexing problem. It seemed that some of the men liked to shave themselves and the others preferred going to a barber. The problem was that the town had no...

Once upon a time there was a town with a perplexing problem. It seemed that some of the men liked to shave themselves and the others preferred going to a barber. The problem was that the town had no barber. To remedy this unfortunate situation, the town began to advertise for a barber who would “shave precisely those men who do not shave themselves.” But try as they might, they had great difficulty finding anyone who could fill the job description. Many good barbers applied, but none of them could do the job that had been advertised. Then one day a mathematician was passing through town and hearing of their difficulty announced, “I am qualified to be your barber.” Without a moment’s hesitation, the townspeople agreed that indeed the mathematician could do the job as advertised. Assuming that this story is true, what was the name of the mathematician? (Hint : It was either Jim, Dave, or Sam.)