A college professor says to his students, "Logical deduction is the art of making a natural series of assumptions based on one fact in order to prove another fact. I'll illustrate. Mr. Norris, do you have a dog?"
Norris says, "Yes, I do."
The professor says, "I deduce that because you have a dog, you have a backyard?"
Norris says, "Yes, I do."
The professor says, "You have a backyard, so you have a house?"
Norris says, "Yes."
The professor says, "Because you have a house, I deduce that you don't live alone?"
Norris says, "Right again."
The professor says, "And because you don't live alone, I deduce that you have a wife?"
Norris says, "Yes, I have a wife."
The professor says, "And because you have a wife, I deduce that you are not a homosexual."
Norris says, "No, I'm not."
After class, one of Norris' dormmates says, "What did you study in that 'Logical Deductions' class?"
Norris says, "I'll show you. Do you have a dog?"
The guy says, "Nope."
Norris says, "You fucking faggot."
