How many times do we have to have a balanced discussion to determine the truth before we accept that, with reasonable certainty, we've determined the truth and

How many times do we have to have a balanced discussion to determine the truth before we accept that, with reasonable certainty, we've determined the truth and can discuss subsequent issues on that basis? I'm not suggesting a flame thread is more productive. I'm suggesting that a civility/debating club fetish keeps us rehashing basics and is itself an impediment to deeper learning.