Kevin Duffy's rules for civil debate

1. It's ok to attack an idea, but not the person. 
2. Pursuit of the truth has to matter. People are entitled to their own opinions, but not their own facts.
3. Respect each other's time. It takes far less time to spew falsehoods than to refute them.
4. Get down to the level of underlying assumptions and foundational beliefs. Otherwise you'll be talking in circles and spinning your wheels.
5. Try to at least find some common ground.  Leave understanding where you agree as well as disagree.