Here at Harvard and MIT, I'm getting to read more history of science--and from the introduction to the classic scientific work The Skeptical Chemist of 1661, I find this great passage that has much bearing on how we discuss contentious issues like science and religion today:
...I am not sorry to have this Opportunity of giving an example how to manage even Disputes with Civility; whence perhaps some Readers will be assisted to discern a Difference betwixt Bluntness of Speech and Strength of reason, and find that a man may be a Champion for Truth, without being an Enemy to Civility; and may confute an Opinion without railing at Them that hold it; To whom he that desires to convince and not to provoke them, must make some amends by his Civility to their Persons, for his severity to their mistakes; and must say as little else as he can, to displease them, when he says they are in an error.
The writer is the man after whom Boyle's Law is named; he was also a devout Christian. I think there is something pretty profound in what Boyle is saying. If we follow his perspective, it may be the case that you can't really have reasoned discussion, at least among those of different views, without a precondition of civility, acceptance, and a lack of condescension. Otherwise, the arguments, however well-based they may be, won't get through, but will only offend; defenses will go up and nobody will give ground--none of which is what we want in reasoned discourse. In other words, no matter what kind of reason-based arguments it contains, discourse might not truly be "reasonable"--in the sense of being meant to promote the spread of reason--unless it is also civil. The two may be inseparable. Granted, I know full well that there are many other reasons for, in Boyle's words, confuting an opinion while also "railing at Them that hold it"--it can be very entertaining, or very motivating to those of us who agree. But does it spread the power of reason to those who do not? That I find hard to believe.