In an in-character argument, the characters naturally need to apply the logic of the game world. The logic of the real world, however, may be very different. Being both a player and the incarnation of a character means you have to weigh your statements doubly carefully to avoid ridiculous assertions.
This also has application to player versus GM arguments. If the GM strikes down something you want to do on logical grounds, you should argue that it makes sense in the game world. After all, your character just tried it, didn't he? A character who is familiar with how reality works in the game world surely wouldn't try something that obviously wouldn't work... so therefore it must work!
And conversely, if the GM forbids you from doing something in the game world, claim that it's true in real life. After all, your ability to use two guns at once in an arcade game clearly demonstrates that your character is able to fire double-handed without any to-hit penalties.
Obi-Wan: What are you doing? We need to go back and pick up Padmé.
Anakin: I won't put her in danger!
Obi-Wan: Anakin, we don't have the authority to deal with Dookû alone. We need Padmé.
Obi-Wan: If we negotiate with Dookû on behalf of the Senate we can end this war right now. She has a job to do.
Anakin: I don't care.
Anakin: Pilot, keep flying!
Obi-Wan: You'll be expelled from the Jedi Order!
Anakin: I can't lead her into a trap. He's a Sith Lord, I tell you! This will be a fight, not a negotiation.
Obi-Wan: Come to your senses. What do you think Padmé would do if she were in your position?
Obi-Wan: Okay, never mind.