Gentlemen never raise their voices. (We were going to capitalize the word “never”, but then we remembered that is the typographical equivalent of shouting.) Their discussions are quiet, but laced with compelling reason and gentle wit. If the matter is not important, a gentleman gracefully concedes, for the sake of peace. The lower the social station of the opponent, the more incumbent upon the gentleman to concede. A gentleman is never a bully.
If one happens to be attending college at Oxford or Yale, prolonged discussions are acceptable. Otherwise, one listens and then, if one disagrees, simply states the truth, simply and clearly. If the fool does not see the light, one gracefully departs and finds more sensible companions. Upon leaving, a simple, “I’m sorry, but I disagree” will suffice.
In the unlikely event that a gentleman learns that he is wrong on a matter of significance, he simply says the following: “I’m sorry; I was wrong”. No more, no less.