Really interesting point from Seth Godin http://sethgodin.typepad.com/seths_blog/2016/08/putting-falsifiability-to-work.html about arguing arguments versus beliefs. I don’t think belief based arguments that are not falsifiable (https://en.wikipedia.org/wiki/Falsifiability) have any place in product ownership decisions and when they do come up they should promptly be dismissed as a belief that isn’t based on an arguable point. They are just opinions and wherever possible we want data driven decisions, not opinions. When presenting an argument for why something should be done in some way I believe it is on the arguer to make their opinion falsifiable, as Seth has pointed out in his post:
“I believe in A because of B and C.”
To throw into the somewhat heated and stormy product decisions that must be made every day that A is the way to go and not provide the why of B and C just prolongs and frustrates the decision. It is on you dear arguer to make your opinion falsifiable or don’t bother bringing it up.
And yes, there is room for decisions based upon pure opinion when presented as a hypothesis that could be tested within minimum viable product guidelines to see if they can achieve a KPI that makes the risk of tackling an opinion, rather than an arguable point, worthwhile. But I wouldn’t tackle these until you have completely expended the arguable points that are in front of you.