It would be a grave mistake to imagine we can change the convictions of anyone even thru the most persuasive arguments we can muster. Fact is, we are wired to deal with our cognitive dissonance by catering to it thru confirmation bias.
Anything that contradicts our cherished beliefs will be rationalized against, or simply categorized as untrue. If any logical fallacy is detected on either side — it will be used as if a bad argument is automatically proof of a false one (which is a fallacy in itself, amusingly called the "fallacy fallacy").
Either way, nobody has changed cherished beliefs on a presumingly lost argument.
But all the rhetoric is not fruitless. I have personally changed my deep beliefs and bias thru the pertinent counter-arguments of others. I went from theist (JW) to atheist. Others are touched the other way around, and go from atheism to theism. So we CAN change through debate and argumentation — but it is always a long process.
Why?
Because some of us have invested a lifetime in a belief or conviction. We have built a circle of peers, like family and friends. We are part of a like-minded community. We don't want to lose our emotional and intellectual investment, nor do we want to disappoint our peers (sometimes even lose them).
I know.
I went thru it all. It almost destroyed me. But the satisfaction of proving to self that we are capable of seriously questioning our biases — and humiliate ourselves if need be — can be pure bliss. It is humbling to find out we can be wrong, but if our quest is for "Truth", we will follow it wherever it leads us, even if it's not where we want it to go. Even if our reputation is at stake.
On the path of this honest journey, there is such a glowing and warm feeling of satisfaction, and happiness peaks to an all-time high. Trust me.
Of course, new understanding is not a guarantee of correct understanding. We need to stay open to the fact that our conversion may have been a mistake. Being open to correction is an ongoing process for as long as we live.
Whatever we believe or not… we are doing something right if we are genuinely happy!
Lasting Happiness is to not kid ourselves.