A beautiful piece here by Paul Graham on How to disagree where he attempts to create a disagreement hierarchy of six different levels from "name calling" to "refuting the central point".
His bottom line is "don't be mean" and his rationale is that it makes people happier.
I don't think howver that this is the main argument. You are more likely to convince people of your point by being "less mean" and moving higher up the hierarchy in you conversational style.
If you enjoyed the above article, I think you will enjoy this one too What you cant say. This comment about Galileo particularly set me chuckling:
"If Galileo had said that people in Padua were ten feet tall, he would have been regarded as a harmless eccentric. Saying the earth orbited the sun was another matter. The church knew this would set people thinking."
Thanks to James Damore (yes the guy who wrote the Google memo) for pointing me to both of these articles via his twitter stream. (You can understand why both articles resonate with him.)
This all makes interesting and relevant fodder for my blook on Conversational Leadership. And it is at the heart of what Knowledge Management should be all about - "making better sense of the world".