"I'm logical and you're not"
I overheard someone talking the other day, and she was claiming she was right because she was logical and the other person was not. It seems that it's common to appeal to whether or not one's position, one's attitude or a particular statement is logical in order to defend what a person is saying. "You're not being logical," a person says, and thus it is implied that what you're saying is either wrong or not worth listening to.
So, here enters one of my favorite questions: "What do you mean by that?"
If a person is appealing to logic for the strength and importance of his position, I would hope that he has a decent grasp on the field of logic. The problem is, I'm not sure many people do. Even less, is my assumption, that people are able to operate this knowledge on the fly and analyze arguments according to their logical training. It's one thing to be able to check the validity of a syllogism expressed in symbolic logic while sitting at a desk with a pen and paper. It's another thing to apply those skills during a conversation.
Thus, when someone says, "Well, I'm being logical," I think a good followup question to ask is "How so?" Do you understand rules of valid inference? If so, does your knowledge extend beyond a simple familiarity with Modus Tollens and Modus Ponens? There is likely more complexity to what a person asserting than can be covered by one or two basic rules of inference. It seems a bit naive to claim you're being logical without being able to explain to someone how it is that you're being logical. So, be careful out there.
If you're being logical then you know how logic works.
You don't know how logic works.
Therefore, you are not being logical (MP)
QED
Note: the first premise is false… I know. I'm trying to be funny, not logical.