Tom and Bob are talking in a bar.
Tom says, "Gotta run. I'm signing up for some college courses, and I have an appointment with the Dean."
Tom meets with the Dean of Admissions, who explains the classes available.
"History, Math, Science, and Logic."
"Logic?" Tom asks. "What's that?"
"Here's an example. Do you own a weed whacker?"
Tom said, "Yes."
"Well, if you own a weed whacker, then logically speaking you own a lawn," the Dean continued.
"Yes, I do!"
"Then you own a big house."
Tom said, "Yes, I do!"
"And if you own a big house, then..."