I see many debates that degenerate because the issue in dispute isn't well defined. Look at many of the locked threads and you will see that the protagonists often appear to misunderstand each other and read things into statements which aren't there.
I think it is best at the outset to find the common ground and then move on to disagreements. If that can be done it generally turns out that there is less disagreement than it may initially appear. Of course that approach is much easier when there are just a few people talking in a room than it is in an on-line forum. But if we could all just try to take that approach I think there would be far less flaming.
