Now, I realize that some out there would tell me that “Debates are unChristian” (and I would happily debate you on that view anytime 😉 ), but to me the quickest way of getting all of the information, facts/viewpoints etc. out into the open and sifting through the morass of conflicting theologies that have arisen since Christ’s ascension is in debate format.
That is: if you want to compare two positions – say, Unitarian and Trinitarian – you may try to read a book (or many) by a Unitarian, then read a book (or many) by a Trinitarian, and try to figure out in the abstract which one makes a more compelling case; that might be helpful, yes. However inevitably the books will not always directly address the issues brought up by one another, and thus you have people just talking past one another and not nailing down the disagreement (unless these books are themselves written to address one another specifically, in which case you simply have a written debate).
A master of rhetoric may just be able to use this system to convince his hearers of falsities – i.e. the true position doesn’t sound as pretty on paper as the false position, and thus the masses ignore their critical thinking capacities and let themselves be deceived by pretty words without challenging the facts and assumptions behind them.
On the other hand, to have the Unitarian and the Trinitarian in the same room, discussing the issues face-to-face and holding one another accountable to the facts and the arguments presented, gives a much clearer picture of the points of disagreement and, indeed, of which case is stronger. In a verbal debate with back-and-forth interaction, specifically in the cross-examination, rhetoric becomes useless and both sides must present an actually cogent case if they wish to survive.
It’s one thing to make heresy sound pretty and compelling in a monolog (Arius was famous for this, incidentally), but a completely different matter to maintain it in a dialogue. For this and other reasons, debates are good, nay, vital, to the sincere seeker of truth.