Real-Life Double Negatives

“Can a Jewish person eat a ham calzone?” I asked my Jewish friend.

She gave me a look that said, “Oh, goodness, I can’t wait to hear this one…”

I continued. “It seems to me that things cancel out. You’re not allowed to eat ham, but you also aren’t allowed to mix meat and cheese, so this is a double negative.”

“Nice try,” she replied. “Just means you get to ride the express elevator to hell.”

The error with my logic, of course, is that sins are additive, not multiplicative. This is actually quite lucky, if you think about it. Otherwise, you’d have to spend your entire life being remarkably fastidious in keeping track of your sins: an even number of sins, you go to heaven; an odd number of sins, you end up a little lower. The graph looks something like this:

I’m not the first to tell a joke involving Jews and double negatives. Stanislaw Ulam did it with this joke from his autobiography:

Two Jews are riding on a train through Russia. One asks the other, “Where are you going?” The second replies, “To Kiev.” Whereupon the first says, “You liar, you tell me you are going to Kiev so I would think you are going to Odessa. But I know you are going to Kiev, so why do you lie?”