Joke Theft

My Fellow Comedists,

This weekend, I am giving a paper at the 4th annual conference of the Lighthearted Philosophers Society. My topic is joke theft. The cardinal sin amongst stand-up comics is stealing someone else's material. But to define joke theft, you need (1) a notion of joke ownership and (2) a notion of joke identity. When I write and perform a joke, what is it I have claim to and when is your joke the same as my joke?

I want to pump some intuitions from the congregation on this topic (easy, Jeff). Tell me if you think the following two jokes are examples of the same joke. The first was written by Will Carey, for my money the best joke writer on the Baltimore/DC circuit -- go see him if you get a chance. The second is mine. Are they the same joke or not? If I performed the second joke on stage (I never have), would Will be justified in accusing me of joke theft?

Will's joke*: I walked into an optimist club it was half empty, but when I left it was half full. They do amazing work.

My joke: They have an Optimists Club, so shouldn't also have a Pessimists Club? I was going to start one, but, nah, it would never work.

His is better, but is it a better joke or a better variant of the same joke?

Live, love, and laugh,

Irreverend Steve

* This joke was used with express permission of Will Carey and let it be duly noted that he was incredibly cool about it, is in no way hypersensitive about joke theft, and has been very thoughtful in correspondence about the topic.